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Liang S, Zhou J, Yu X, Lu S, Liu R. Neuronal conversion from glia to replenish the lost neurons. Neural Regen Res 2024; 19:1446-1453. [PMID: 38051886 PMCID: PMC10883502 DOI: 10.4103/1673-5374.386400] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 08/16/2023] [Indexed: 12/07/2023] Open
Abstract
ABSTRACT Neuronal injury, aging, and cerebrovascular and neurodegenerative diseases such as cerebral infarction, Alzheimer's disease, Parkinson's disease, frontotemporal dementia, amyotrophic lateral sclerosis, and Huntington's disease are characterized by significant neuronal loss. Unfortunately, the neurons of most mammals including humans do not possess the ability to self-regenerate. Replenishment of lost neurons becomes an appealing therapeutic strategy to reverse the disease phenotype. Transplantation of pluripotent neural stem cells can supplement the missing neurons in the brain, but it carries the risk of causing gene mutation, tumorigenesis, severe inflammation, and obstructive hydrocephalus induced by brain edema. Conversion of neural or non-neural lineage cells into functional neurons is a promising strategy for the diseases involving neuron loss, which may overcome the above-mentioned disadvantages of neural stem cell therapy. Thus far, many strategies to transform astrocytes, fibroblasts, microglia, Müller glia, NG2 cells, and other glial cells to mature and functional neurons, or for the conversion between neuronal subtypes have been developed through the regulation of transcription factors, polypyrimidine tract binding protein 1 (PTBP1), and small chemical molecules or are based on a combination of several factors and the location in the central nervous system. However, some recent papers did not obtain expected results, and discrepancies exist. Therefore, in this review, we discuss the history of neuronal transdifferentiation, summarize the strategies for neuronal replenishment and conversion from glia, especially astrocytes, and point out that biosafety, new strategies, and the accurate origin of the truly converted neurons in vivo should be focused upon in future studies. It also arises the attention of replenishing the lost neurons from glia by gene therapies such as up-regulation of some transcription factors or down-regulation of PTBP1 or drug interference therapies.
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Affiliation(s)
- Shiyu Liang
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Jing Zhou
- Department of Geriatric Rehabilitation, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| | - Xiaolin Yu
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Shuai Lu
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Ruitian Liu
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
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2
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Joglekar A, Hu W, Zhang B, Narykov O, Diekhans M, Marrocco J, Balacco J, Ndhlovu LC, Milner TA, Fedrigo O, Jarvis ED, Sheynkman G, Korkin D, Ross ME, Tilgner HU. Single-cell long-read sequencing-based mapping reveals specialized splicing patterns in developing and adult mouse and human brain. Nat Neurosci 2024; 27:1051-1063. [PMID: 38594596 PMCID: PMC11156538 DOI: 10.1038/s41593-024-01616-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 03/07/2024] [Indexed: 04/11/2024]
Abstract
RNA isoforms influence cell identity and function. However, a comprehensive brain isoform map was lacking. We analyze single-cell RNA isoforms across brain regions, cell subtypes, developmental time points and species. For 72% of genes, full-length isoform expression varies along one or more axes. Splicing, transcription start and polyadenylation sites vary strongly between cell types, influence protein architecture and associate with disease-linked variation. Additionally, neurotransmitter transport and synapse turnover genes harbor cell-type variability across anatomical regions. Regulation of cell-type-specific splicing is pronounced in the postnatal day 21-to-postnatal day 28 adolescent transition. Developmental isoform regulation is stronger than regional regulation for the same cell type. Cell-type-specific isoform regulation in mice is mostly maintained in the human hippocampus, allowing extrapolation to the human brain. Conversely, the human brain harbors additional cell-type specificity, suggesting gain-of-function isoforms. Together, this detailed single-cell atlas of full-length isoform regulation across development, anatomical regions and species reveals an unappreciated degree of isoform variability across multiple axes.
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Affiliation(s)
- Anoushka Joglekar
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
- Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA
- New York Genome Center, New York, NY, USA
| | - Wen Hu
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
- Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA
| | - Bei Zhang
- Spatial Genomics, Inc., Pasadena, CA, USA
| | - Oleksandr Narykov
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA
- Computer Science Department, Worcester Polytechnic Institute, Worcester, MA, USA
- Data Science Program, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Mark Diekhans
- UC Genomics Institute, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Jordan Marrocco
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
- Department of Biology, Touro University, New York, NY, USA
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA
| | - Jennifer Balacco
- Vertebrate Genome Lab, The Rockefeller University, New York, NY, USA
| | - Lishomwa C Ndhlovu
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York, NY, USA
| | - Teresa A Milner
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Olivier Fedrigo
- Vertebrate Genome Lab, The Rockefeller University, New York, NY, USA
| | - Erich D Jarvis
- Vertebrate Genome Lab, The Rockefeller University, New York, NY, USA
- Laboratory of Neurogenetics of Language, The Rockefeller University, New York, NY, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Gloria Sheynkman
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA, USA
- UVA Comprehensive Cancer Center, University of Virginia, Charlottesville, VA, USA
| | - Dmitry Korkin
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA
- Computer Science Department, Worcester Polytechnic Institute, Worcester, MA, USA
- Data Science Program, Worcester Polytechnic Institute, Worcester, MA, USA
| | - M Elizabeth Ross
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
- Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA
| | - Hagen U Tilgner
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
- Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA.
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3
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Wolfe Z, Liska D, Norris A. Deep Transcriptomics Reveals Cell-Specific Isoforms of Pan-Neuronal Genes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.16.594572. [PMID: 38826410 PMCID: PMC11142100 DOI: 10.1101/2024.05.16.594572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Profiling gene expression in single neurons using single-cell RNA-Seq is a powerful method for understanding the molecular diversity of the nervous system. Profiling alternative splicing in single neurons using these methods is more challenging, however, due to low capture efficiency and sensitivity. As a result, we know much less about splicing patterns and regulation across neurons than we do about gene expression. Here we leverage unique attributes of the C. elegans nervous system to investigate deep cell-specific transcriptomes complete with biological replicates generated by the CeNGEN consortium, enabling high-confidence assessment of splicing across neuron types even for lowly-expressed genes. Global splicing maps reveal several striking observations, including pan-neuronal genes that harbor cell-specific splice variants, abundant differential intron retention across neuron types, and a single neuron highly enriched for upstream alternative 3' splice sites. We develop an algorithm to identify unique cell-specific expression patterns and use it to discover both cell-specific isoforms and potential regulatory RNA binding proteins that establish these isoforms. Genetic interrogation of these RNA binding proteins in vivo identifies three distinct regulatory factors employed to establish unique splicing patterns in a single neuron. Finally, we develop a user-friendly platform for spatial transcriptomic visualization of these splicing patterns with single-neuron resolution.
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4
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Yuan CU, Quah FX, Hemberg M. Single-cell and spatial transcriptomics: Bridging current technologies with long-read sequencing. Mol Aspects Med 2024; 96:101255. [PMID: 38368637 DOI: 10.1016/j.mam.2024.101255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/30/2024] [Accepted: 02/07/2024] [Indexed: 02/20/2024]
Abstract
Single-cell technologies have transformed biomedical research over the last decade, opening up new possibilities for understanding cellular heterogeneity, both at the genomic and transcriptomic level. In addition, more recent developments of spatial transcriptomics technologies have made it possible to profile cells in their tissue context. In parallel, there have been substantial advances in sequencing technologies, and the third generation of methods are able to produce reads that are tens of kilobases long, with error rates matching the second generation short reads. Long reads technologies make it possible to better map large genome rearrangements and quantify isoform specific abundances. This further improves our ability to characterize functionally relevant heterogeneity. Here, we show how researchers have begun to combine single-cell, spatial transcriptomics, and long-read technologies, and how this is resulting in powerful new approaches to profiling both the genome and the transcriptome. We discuss the achievements so far, and we highlight remaining challenges and opportunities.
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Affiliation(s)
- Chengwei Ulrika Yuan
- Department of Biochemistry, University of Cambridge, Cambridge, UK; Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK
| | - Fu Xiang Quah
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Martin Hemberg
- Gene Lay Institute, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
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5
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Zhu J, Zhang J, Hu P, Fan M, Song D, Yin H, Yan P, Xian S, Li Z, Guo J, Long C, Xu R, Huang R, Meng T, Zhang J, Huang Z. Identification of Bone Metastatic and Prognostic Alternative Splicing Signatures in Prostate Adenocarcinoma. Biochem Genet 2023; 61:2242-2259. [PMID: 37010714 PMCID: PMC10665256 DOI: 10.1007/s10528-023-10367-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 08/07/2022] [Indexed: 04/04/2023]
Abstract
As the most common nonepithelial malignancy, prostate adenocarcinoma (PRAD) is the fifth chief cause of cancer mortality in men. Distant metastasis often occurs in advanced PRAD and most patients are dying from it. However, the mechanism of PRAD progression and metastasis is still unclear. It's widely reported that more than 94% of genes are selectively splicing in humans and many isoforms are particularly related with cancer progression and metastasis. Spliceosome mutations occur in a mutually exclusive manner in breast cancer, and different components of spliceosomes are targets of somatic mutations in different types of breast cancer. Existing evidence strongly supports the key role of alternative splicing in breast cancer biology, and innovative tools are being developed to use splicing events for diagnostic and therapeutic purposes. In order to identify if the PRAD metastasis is associated with alternative splicing events (ASEs), the RNA sequencing data and ASEs data of 500 PRAD patients were retrieved from The Cancer Genome Atlas (TCGA) and TCGASpliceSeq databases. By Lasso regression, five genes were screened to construct the prediction model, with a good reliability by ROC curve. Additionally, results in both univariate and multivariate Cox regression analysis confirmed the well prognosis efficacy of the prediction model (both P < 0.001). Moreover, a potential splicing regulatory network was established and after multiple-database validation, we supposed that the signaling axis of HSPB1 up-regulating the PIP5K1C - 46,721 - AT (P < 0.001) might mediate the tumorigenesis, progression and metastasis of PRAD via the key members of Alzheimer's disease pathway (SRC, EGFR, MAPT, APP and PRKCA) (P < 0.001).
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Affiliation(s)
- Jiwen Zhu
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, 1 East Jianshe Road, Zhengzhou, 450052, China
- Division of Spine, Department of Orthopedics, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, 200065, China
- Tongji University School of Medicine, Shanghai, 200092, China
| | - Jiayao Zhang
- School of Mathematical Sciences of Tongji University, Shanghai, 200092, China
| | - Peng Hu
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, 1 East Jianshe Road, Zhengzhou, 450052, China
| | - Mingxiang Fan
- Tongji University School of Medicine, Shanghai, 200092, China
| | - Dianwen Song
- Department of Orthopedics, School of Medicine, Shanghai General Hospital, Shanghai Jiaotong University, 100 Haining Road, Shanghai, 200065, China
| | - Huabin Yin
- Department of Orthopedics, School of Medicine, Shanghai General Hospital, Shanghai Jiaotong University, 100 Haining Road, Shanghai, 200065, China
| | - Penghui Yan
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, 1 East Jianshe Road, Zhengzhou, 450052, China
| | - Shuyuan Xian
- Tongji University School of Medicine, Shanghai, 200092, China
| | - Zhenyu Li
- Tongji University School of Medicine, Shanghai, 200092, China
| | - Juanru Guo
- School of Mathematical Sciences of Tongji University, Shanghai, 200092, China
| | - Chunling Long
- Tongji University School of Medicine, Shanghai, 200092, China
| | - Runping Xu
- Tongji University School of Medicine, Shanghai, 200092, China
| | - Runzhi Huang
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, 1 East Jianshe Road, Zhengzhou, 450052, China.
- Division of Spine, Department of Orthopedics, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, 200065, China.
- Tongji University School of Medicine, Shanghai, 200092, China.
| | - Tong Meng
- Division of Spine, Department of Orthopedics, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, 200065, China.
- Department of Orthopedics, School of Medicine, Shanghai General Hospital, Shanghai Jiaotong University, 100 Haining Road, Shanghai, 200065, China.
| | - Jie Zhang
- Tongji University School of Medicine, Shanghai, 200092, China.
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 201204, China.
| | - Zongqiang Huang
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, 1 East Jianshe Road, Zhengzhou, 450052, China.
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6
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Taylor M, Marx O, Norris A. TDP-1 and FUST-1 co-inhibit exon inclusion and control fertility together with transcriptional regulation. Nucleic Acids Res 2023; 51:9610-9628. [PMID: 37587694 PMCID: PMC10570059 DOI: 10.1093/nar/gkad665] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/20/2023] [Accepted: 08/09/2023] [Indexed: 08/18/2023] Open
Abstract
Gene expression is a multistep process and crosstalk among regulatory layers plays an important role in coordinating gene expression. To identify functionally relevant gene expression coordination, we performed a systematic reverse-genetic interaction screen in C. elegans, combining RNA binding protein (RBP) and transcription factor (TF) mutants to generate over 100 RBP;TF double mutants. We identified many unexpected double mutant phenotypes, including two strong genetic interactions between the ALS-related RBPs, fust-1 and tdp-1, and the homeodomain TF ceh-14. Losing any one of these genes alone has no effect on the health of the organism. However, fust-1;ceh-14 and tdp-1;ceh-14 double mutants both exhibit strong temperature-sensitive fertility defects. Both double mutants exhibit defects in gonad morphology, sperm function, and oocyte function. RNA-Seq analysis of double mutants identifies ceh-14 as the main controller of transcript levels, while fust-1 and tdp-1 control splicing through a shared role in exon inhibition. A skipped exon in the polyglutamine-repeat protein pqn-41 is aberrantly included in tdp-1 mutants, and genetically forcing this exon to be skipped in tdp-1;ceh-14 double mutants rescues their fertility. Together our findings identify a novel shared physiological role for fust-1 and tdp-1 in promoting C. elegans fertility and a shared molecular role in exon inhibition.
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Affiliation(s)
- Morgan Taylor
- Southern Methodist University, Dallas, TX 75205, USA
| | - Olivia Marx
- Southern Methodist University, Dallas, TX 75205, USA
| | - Adam Norris
- Southern Methodist University, Dallas, TX 75205, USA
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7
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Puri D, Sharma S, Samaddar S, Ravivarma S, Banerjee S, Ghosh-Roy A. Muscleblind-1 interacts with tubulin mRNAs to regulate the microtubule cytoskeleton in C. elegans mechanosensory neurons. PLoS Genet 2023; 19:e1010885. [PMID: 37603562 PMCID: PMC10470942 DOI: 10.1371/journal.pgen.1010885] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 08/31/2023] [Accepted: 07/26/2023] [Indexed: 08/23/2023] Open
Abstract
Regulation of the microtubule cytoskeleton is crucial for the development and maintenance of neuronal architecture, and recent studies have highlighted the significance of regulated RNA processing in the establishment and maintenance of neural circuits. In a genetic screen conducted using mechanosensory neurons of C. elegans, we identified a mutation in muscleblind-1/mbl-1 as a suppressor of loss of kinesin-13 family microtubule destabilizing factor klp-7. Muscleblind-1(MBL-1) is an RNA-binding protein that regulates the splicing, localization, and stability of RNA. Our findings demonstrate that mbl-1 is required cell-autonomously for axon growth and proper synapse positioning in the posterior lateral microtubule (PLM) neuron. Loss of mbl-1 leads to increased microtubule dynamics and mixed orientation of microtubules in the anterior neurite of PLM. These defects are also accompanied by abnormal axonal transport of the synaptic protein RAB-3 and reduction of gentle touch sensation in mbl-1 mutant. Our data also revealed that mbl-1 is genetically epistatic to mec-7 (β tubulin) and mec-12 (α tubulin) in regulating axon growth. Furthermore, mbl-1 is epistatic to sad-1, an ortholog of BRSK/Brain specific-serine/threonine kinase and a known regulator of synaptic machinery, for synapse formation at the correct location of the PLM neurite. Notably, the immunoprecipitation of MBL-1 resulted in the co-purification of mec-7, mec-12, and sad-1 mRNAs, suggesting a direct interaction between MBL-1 and these transcripts. Additionally, mbl-1 mutants exhibited reduced levels and stability of mec-7 and mec-12 transcripts. Our study establishes a previously unknown link between RNA-binding proteins and cytoskeletal machinery, highlighting their crucial roles in the development and maintenance of the nervous system.
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Affiliation(s)
- Dharmendra Puri
- National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Sunanda Sharma
- National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Sarbani Samaddar
- National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Sruthy Ravivarma
- National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Sourav Banerjee
- National Brain Research Centre, Manesar, Gurgaon, Haryana, India
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8
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Mullari M, Fossat N, Skotte NH, Asenjo-Martinez A, Humphreys DT, Bukh J, Kirkeby A, Scheel TKH, Nielsen ML. Characterising the RNA-binding protein atlas of the mammalian brain uncovers RBM5 misregulation in mouse models of Huntington's disease. Nat Commun 2023; 14:4348. [PMID: 37468457 DOI: 10.1038/s41467-023-39936-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/30/2023] [Indexed: 07/21/2023] Open
Abstract
RNA-binding proteins (RBPs) are key players regulating RNA processing and are associated with disorders ranging from cancer to neurodegeneration. Here, we present a proteomics workflow for large-scale identification of RBPs and their RNA-binding regions in the mammalian brain identifying 526 RBPs. Analysing brain tissue from males of the Huntington's disease (HD) R6/2 mouse model uncovered differential RNA-binding of the alternative splicing regulator RBM5. Combining several omics workflows, we show that RBM5 binds differentially to transcripts enriched in pathways of neurodegeneration in R6/2 brain tissue. We further find these transcripts to undergo changes in splicing and demonstrate that RBM5 directly regulates these changes in human neurons derived from embryonic stem cells. Finally, we reveal that RBM5 interacts differently with several known huntingtin interactors and components of huntingtin aggregates. Collectively, we demonstrate the applicability of our method for capturing RNA interactor dynamics in the contexts of tissue and disease.
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Affiliation(s)
- Meeli Mullari
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Nicolas Fossat
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- CO-HEP, Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
| | - Niels H Skotte
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Andrea Asenjo-Martinez
- The Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW) and Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - David T Humphreys
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, 2010, Australia
| | - Jens Bukh
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- CO-HEP, Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
| | - Agnete Kirkeby
- The Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW) and Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
- Wallenberg Center for Molecular Medicine (WCMM) and Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Troels K H Scheel
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- CO-HEP, Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Michael L Nielsen
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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9
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Joglekar A, Hu W, Zhang B, Narykov O, Diekhans M, Balacco J, Ndhlovu LC, Milner TA, Fedrigo O, Jarvis ED, Sheynkman G, Korkin D, Ross ME, Tilgner HU. Single-cell long-read mRNA isoform regulation is pervasive across mammalian brain regions, cell types, and development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.02.535281. [PMID: 37066387 PMCID: PMC10103983 DOI: 10.1101/2023.04.02.535281] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
RNA isoforms influence cell identity and function. Until recently, technological limitations prevented a genome-wide appraisal of isoform influence on cell identity in various parts of the brain. Using enhanced long-read single-cell isoform sequencing, we comprehensively analyze RNA isoforms in multiple mouse brain regions, cell subtypes, and developmental timepoints from postnatal day 14 (P14) to adult (P56). For 75% of genes, full-length isoform expression varies along one or more axes of phenotypic origin, underscoring the pervasiveness of isoform regulation across multiple scales. As expected, splicing varies strongly between cell types. However, certain gene classes including neurotransmitter release and reuptake as well as synapse turnover, harbor significant variability in the same cell type across anatomical regions, suggesting differences in network activity may influence cell-type identity. Glial brain-region specificity in isoform expression includes strong poly(A)-site regulation, whereas neurons have stronger TSS regulation. Furthermore, developmental patterns of cell-type specific splicing are especially pronounced in the murine adolescent transition from P21 to P28. The same cell type traced across development shows more isoform variability than across adult anatomical regions, indicating a coordinated modulation of functional programs dictating neural development. As most cell-type specific exons in P56 mouse hippocampus behave similarly in newly generated data from human hippocampi, these principles may be extrapolated to human brain. However, human brains have evolved additional cell-type specificity in splicing, suggesting gain-of-function isoforms. Taken together, we present a detailed single-cell atlas of full-length brain isoform regulation across development and anatomical regions, providing a previously unappreciated degree of isoform variability across multiple scales of the brain.
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Affiliation(s)
- Anoushka Joglekar
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
- Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA
| | - Wen Hu
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
- Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA
| | | | - Oleksandr Narykov
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA
- Computer Science Department, Worcester Polytechnic Institute, Worcester, MA, USA
- Data Science Program, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Mark Diekhans
- UC Santa Cruz Genomics Institute, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | | | - Lishomwa C Ndhlovu
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
- Department of Medicine, Division of Infectious Diseases, Weill Cornell Medicine, New York, NY, USA
| | - Teresa A Milner
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Olivier Fedrigo
- Vertebrate Genome Lab, the Rockefeller University, New York, NY
| | - Erich D Jarvis
- Vertebrate Genome Lab, the Rockefeller University, New York, NY
- Laboratory of Neurogenetics of Language, the Rockefeller University, New York, NY
- Howard Hughes Medical Institute, Chevy Chase, MD
| | - Gloria Sheynkman
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA, USA
- UVA Comprehensive Cancer Center, University of Virginia, Charlottesville, Virginia, USA
| | - Dmitry Korkin
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA
- Computer Science Department, Worcester Polytechnic Institute, Worcester, MA, USA
- Data Science Program, Worcester Polytechnic Institute, Worcester, MA, USA
| | - M Elizabeth Ross
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
- Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA
| | - Hagen U Tilgner
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
- Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA
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10
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Nikolaou N, Gordon PM, Hamid F, Taylor R, Lloyd-Jones J, Makeyev EV, Houart C. Cytoplasmic pool of U1 spliceosome protein SNRNP70 shapes the axonal transcriptome and regulates motor connectivity. Curr Biol 2022; 32:5099-5115.e8. [PMID: 36384140 DOI: 10.1016/j.cub.2022.10.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 09/09/2022] [Accepted: 10/21/2022] [Indexed: 11/17/2022]
Abstract
Regulation of pre-mRNA splicing and polyadenylation plays a profound role in neurons by diversifying the proteome and modulating gene expression in response to physiological cues. Although most of the pre-mRNA processing is thought to occur in the nucleus, numerous splicing regulators are also found in neurites. Here, we show that U1-70K/SNRNP70, a component of the major spliceosome, localizes in RNA-associated granules in zebrafish axons. We identify the extra-nuclear SNRNP70 as an important regulator of motor axonal growth, nerve-dependent acetylcholine receptor (AChR) clustering, and neuromuscular synaptogenesis. This cytoplasmic pool has a protective role for a limited number of transcripts regulating their abundance and trafficking inside axons. Moreover, non-nuclear SNRNP70 regulates splice variants of transcripts such as agrin, thereby controlling synapse formation. Our results point to an unexpected, yet essential, function of non-nuclear SNRNP70 in axonal development, indicating a role of spliceosome proteins in cytoplasmic RNA metabolism during neuronal connectivity.
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Affiliation(s)
- Nikolas Nikolaou
- Centre for Developmental Neurobiology MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK; Department of Life Sciences, University of Bath, Bath BA2 7AY, UK.
| | - Patricia M Gordon
- Centre for Developmental Neurobiology MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Fursham Hamid
- Centre for Developmental Neurobiology MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Richard Taylor
- Centre for Developmental Neurobiology MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | | | - Eugene V Makeyev
- Centre for Developmental Neurobiology MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Corinne Houart
- Centre for Developmental Neurobiology MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK.
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11
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Fisher E, Feng J. RNA splicing regulators play critical roles in neurogenesis. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1728. [PMID: 35388651 DOI: 10.1002/wrna.1728] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/07/2022] [Accepted: 03/09/2022] [Indexed: 06/14/2023]
Abstract
Alternative RNA splicing increases transcript diversity in different cell types and under varying conditions. It is executed with the help of RNA splicing regulators (RSRs), which are operationally defined as RNA-binding proteins (RBPs) that regulate alternative splicing, but not directly catalyzing the chemical reactions of splicing. By systematically searching for RBPs and manually identifying those that regulate splicing, we curated 305 RSRs in the human genome. Surprisingly, most of the RSRs are involved in neurogenesis. Among these RSRs, we focus on nine families (PTBP, NOVA, RBFOX, ELAVL, CELF, DBHS, MSI, PCBP, and MBNL) that play essential roles in the neurogenic pathway. A better understanding of their functions will provide novel insights into the role of splicing in brain development, health, and disease. This comprehensive review serves as a stepping-stone to explore the diverse and complex set of RSRs as fundamental regulators of neural development. This article is categorized under: RNA-Based Catalysis > RNA Catalysis in Splicing and Translation RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
- Emily Fisher
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York, USA
- Veterans Affairs Western New York Healthcare System, Buffalo, New York, USA
| | - Jian Feng
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York, USA
- Veterans Affairs Western New York Healthcare System, Buffalo, New York, USA
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12
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Mol P, Gopalakrishnan L, Chatterjee O, Mangalaparthi KK, Kumar M, Durgad SS, Nair B, Shankar SK, Mahadevan A, Prasad TSK. Proteomic Analysis of Adult Human Hippocampal Subfields Demonstrates Regional Heterogeneity in the Protein Expression. J Proteome Res 2022; 21:2293-2310. [PMID: 36039803 DOI: 10.1021/acs.jproteome.2c00143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Background: Distinct hippocampal subfields are known to get affected during aging, psychiatric disorders, and various neurological and neurodegenerative conditions. To understand the biological processes associated with each subfield, it is important to understand its heterogeneity at the molecular level. To address this lacuna, we investigated the proteomic analysis of hippocampal subfields─the cornu ammonis sectors (CA1, CA2, CA3, CA4) and dentate gyrus (DG) from healthy adult human cohorts. Findings: Microdissection of hippocampal subfields from archived formalin-fixed paraffin-embedded tissue sections followed by TMT-based multiplexed proteomic analysis resulted in the identification of 5,593 proteins. Out of these, 890 proteins were found to be differentially abundant among the subfields. Further bioinformatics analysis suggested proteins related to gene splicing, transportation, myelination, structural activity, and learning processes to be differentially abundant in DG, CA4, CA3, CA2, and CA1, respectively. A subset of proteins was selected for immunohistochemistry-based validation in an independent set of hippocampal samples. Conclusions: We believe that our findings will effectively pave the way for further analysis of the hippocampal subdivisions and provide awareness of its subfield-specific association to various neurofunctional anomalies in the future. The current mass spectrometry data is deposited and publicly made available through ProteomeXchange Consortium via the PRIDE partner repository with the data set identifier PXD029697.
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Affiliation(s)
- Praseeda Mol
- Institute of Bioinformatics, International Technology Park, Whitefield, Bangalore 560066,India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690525, India
| | - Lathika Gopalakrishnan
- Institute of Bioinformatics, International Technology Park, Whitefield, Bangalore 560066,India.,Centre for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore 575018, India.,Manipal Academy of Higher Education, Manipal 576104, India
| | - Oishi Chatterjee
- Institute of Bioinformatics, International Technology Park, Whitefield, Bangalore 560066,India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690525, India.,Centre for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore 575018, India
| | - Kiran K Mangalaparthi
- Institute of Bioinformatics, International Technology Park, Whitefield, Bangalore 560066,India.,Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690525, India
| | - Manish Kumar
- Institute of Bioinformatics, International Technology Park, Whitefield, Bangalore 560066,India.,Manipal Academy of Higher Education, Manipal 576104, India
| | - Shwetha S Durgad
- Human Brain Tissue Repository, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Bipin Nair
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690525, India
| | - Susarla K Shankar
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India.,Human Brain Tissue Repository, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Anita Mahadevan
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India.,Human Brain Tissue Repository, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
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13
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Liang X, Calovich-Benne C, Norris A. Sensory neuron transcriptomes reveal complex neuron-specific function and regulation of mec-2/Stomatin splicing. Nucleic Acids Res 2021; 50:2401-2416. [PMID: 34875684 PMCID: PMC8934639 DOI: 10.1093/nar/gkab1134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/30/2021] [Accepted: 11/09/2021] [Indexed: 12/16/2022] Open
Abstract
The function and identity of a cell is shaped by transcription factors controlling transcriptional networks, and further shaped by RNA binding proteins controlling post-transcriptional networks. To overcome limitations inherent to analysis of sparse single-cell post-transcriptional data, we leverage the invariant Caenorhabditis elegans cell lineage, isolating thousands of identical neuron types from thousands of isogenic individuals. The resulting deep transcriptomes facilitate splicing network analysis due to increased sequencing depth and uniformity. We focus on mechanosensory touch-neuron splicing regulated by MEC-8/RBPMS. We identify a small MEC-8-regulated network, where MEC-8 establishes touch-neuron isoforms differing from default isoforms found in other cells. MEC-8 establishes the canonical long mec-2/Stomatin isoform in touch neurons, but surprisingly the non-canonical short isoform predominates in other neurons, including olfactory neurons, and mec-2 is required for olfaction. Forced endogenous isoform-specific expression reveals that the short isoform functions in olfaction but not mechanosensation. The long isoform is functional in both processes. Remarkably, restoring the long isoform completely rescues mec-8 mutant mechanosensation, indicating a single MEC-8 touch-neuron target is phenotypically relevant. Within the long isoform we identify a cassette exon further diversifying mec-2 into long/extra-long isoforms. Neither is sufficient for mechanosensation. Both are simultaneously required, likely functioning as heteromers to mediate mechanosensation.
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Affiliation(s)
- Xiaoyu Liang
- Southern Methodist University, Dallas, TX 75275, USA
| | | | - Adam Norris
- Southern Methodist University, Dallas, TX 75275, USA
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14
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A pan-cancer analysis of alternative splicing of splicing factors in 6904 patients. Oncogene 2021; 40:5441-5450. [PMID: 34285345 DOI: 10.1038/s41388-021-01947-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 07/01/2021] [Accepted: 07/08/2021] [Indexed: 02/07/2023]
Abstract
Great progress has been made in the investigation on mutation and expression of splicing factor. However, little is known on the role of alternative splicing of splicing factors across cancers. Here, we reported a pan-cancer analysis of alternative splicing of splicing factors spanning 6904 patients across 16 cancer types, and identified 167 splicing factors with implications regulating cancer-specific splicing patterns through alternative splicing. Furthermore, we found that abnormal splicing events of splicing factors could serve as potential common regulators for alternative splicing in different cancers. In addition, we developed a splicing-derived neoepitopes database (ASPNs), which provided the corresponding putative alternative splicing-derived neoepitopes of 16 cancer types. Our results suggested that alternative splicing of splicing factors involved in the pre-RNA splicing process was common across cancer types and may represent an underestimated hallmark of tumorigenesis.
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15
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Lin J, Wu S, Shen Q, Liu J, Huang S, Peng G, Qiao Y. Base editing-mediated perturbation of endogenous PKM1/2 splicing facilitates isoform-specific functional analysis in vitro and in vivo. Cell Prolif 2021; 54:e13096. [PMID: 34240779 PMCID: PMC8349652 DOI: 10.1111/cpr.13096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/02/2021] [Accepted: 06/27/2021] [Indexed: 01/05/2023] Open
Abstract
OBJECTIVES PKM1 and PKM2, which are generated from the alternative splicing of PKM gene, play important roles in tumourigenesis and embryonic development as rate-limiting enzymes in glycolytic pathway. However, because of the lack of appropriate techniques, the specific functions of the 2 PKM splicing isoforms have not been clarified endogenously yet. MATERIALS AND METHODS In this study, we used CRISPR-based base editors to perturbate the endogenous alternative splicing of PKM by introducing mutations into the splicing junction sites in HCT116 cells and zebrafish embryos. Sanger sequencing, agarose gel electrophoresis and targeted deep sequencing assays were utilized for identifying mutation efficiencies and detecting PKM1/2 splicing isoforms. Cell proliferation assays and RNA-seq analysis were performed to describe the effects of perturbation of PKM1/2 splicing in tumour cell growth and zebrafish embryo development. RESULTS The splicing sites of PKM, a 5' donor site of GT and a 3' acceptor site of AG, were efficiently mutated by cytosine base editor (CBE; BE4max) and adenine base editor (ABE; ABEmax-NG) with guide RNAs (gRNAs) targeting the splicing sites flanking exons 9 and 10 in HCT116 cells and/or zebrafish embryos. The mutations of the 5' donor sites of GT flanking exons 9 or 10 into GC resulted in specific loss of PKM1 or PKM2 expression as well as the increase in PKM2 or PKM1 respectively. Specific loss of PKM1 promoted cell proliferation of HCT116 cells and upregulated the expression of cell cycle regulators related to DNA replication and cell cycle phase transition. In contrast, specific loss of PKM2 suppressed cell growth of HCT116 cells and resulted in growth retardation of zebrafish. Meanwhile, we found that mutation of PKM1/2 splicing sites also perturbated the expression of non-canonical PKM isoforms and produced some novel splicing isoforms. CONCLUSIONS This work proved that CRISPR-based base editing strategy can be used to disrupt the endogenous alternative splicing of genes of interest to study the function of specific splicing isoforms in vitro and in vivo. It also reminded us to notice some novel or undesirable splicing isoforms by targeting the splicing junction sites using base editors. In sum, we establish a platform to perturbate endogenous RNA splicing for functional investigation or genetic correction of abnormal splicing events in human diseases.
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Affiliation(s)
- Jianxiang Lin
- Precise Genome Engineering CenterSchool of Life SciencesGuangzhou UniversityGuangzhouChina
| | - Susu Wu
- Precise Genome Engineering CenterSchool of Life SciencesGuangzhou UniversityGuangzhouChina
| | - Qingmei Shen
- Centre for Cell Lineage and Atlas (CCLA), Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory)GuangzhouChina
| | - Jie Liu
- Precise Genome Engineering CenterSchool of Life SciencesGuangzhou UniversityGuangzhouChina
| | - Shisheng Huang
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
| | - Guangdun Peng
- Centre for Cell Lineage and Atlas (CCLA), Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory)GuangzhouChina
| | - Yunbo Qiao
- Precise Genome Engineering CenterSchool of Life SciencesGuangzhou UniversityGuangzhouChina
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16
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Systematic Profiling of mRNA Splicing Reveals the Prognostic Predictor and Potential Therapeutic Target for Glioblastoma Multiforme. JOURNAL OF ONCOLOGY 2021; 2021:4664955. [PMID: 34326872 PMCID: PMC8277521 DOI: 10.1155/2021/4664955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/17/2021] [Accepted: 06/22/2021] [Indexed: 11/17/2022]
Abstract
Despite many changes in alternative splicing events (ASEs) are frequently involved in various cancers, prognosis-related ASEs and drug treatment targets in glioblastoma multiforme (GBM) have not been well explored. ASEs participate in many biological behaviors in the initiation and progression of tumors, the aberrant ASE has been considered another hallmark of cancer, and the systematic study of alternative splicing may provide potential biomarkers for malignancies. In this study, we carried out a systematic analysis to characterize the ASE signatures in GBM cohort. Through comparing GBM tissues and nontumor tissues, a total of 48,191 differently expressed ASEs from 10,727 genes were obtained, and these aberrant ASEs play an important role in the oncogenic process. Then, we identified 514 ASEs independently associated with patient survival in GBM by univariate and multivariate Cox regression, including exon skip in CD3D, alternate acceptor site in POLD2, and exon skip in DCN. Those prognostic models built on ASEs of each splice type can accurately predict the outcome of GBM patients, and values for the area under curve were 0.97 in the predictive model based on alternate acceptor site. In addition, the splicing-regulatory network revealed an interesting correlation between survival-associated splicing factors and prognostic ASE corresponding genes. Moreover, these three hub splicing factors in splicing regulation network are the potential targets of some drugs. In conclusion, a systematic analysis of ASE signatures in GBM could serve as an indicator for identifying novel prognostic biomarkers and guiding clinical treatment.
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17
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Joglekar A, Prjibelski A, Mahfouz A, Collier P, Lin S, Schlusche AK, Marrocco J, Williams SR, Haase B, Hayes A, Chew JG, Weisenfeld NI, Wong MY, Stein AN, Hardwick SA, Hunt T, Wang Q, Dieterich C, Bent Z, Fedrigo O, Sloan SA, Risso D, Jarvis ED, Flicek P, Luo W, Pitt GS, Frankish A, Smit AB, Ross ME, Tilgner HU. A spatially resolved brain region- and cell type-specific isoform atlas of the postnatal mouse brain. Nat Commun 2021; 12:463. [PMID: 33469025 PMCID: PMC7815907 DOI: 10.1038/s41467-020-20343-5] [Citation(s) in RCA: 88] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/27/2020] [Indexed: 01/19/2023] Open
Abstract
Splicing varies across brain regions, but the single-cell resolution of regional variation is unclear. We present a single-cell investigation of differential isoform expression (DIE) between brain regions using single-cell long-read sequencing in mouse hippocampus and prefrontal cortex in 45 cell types at postnatal day 7 ( www.isoformAtlas.com ). Isoform tests for DIE show better performance than exon tests. We detect hundreds of DIE events traceable to cell types, often corresponding to functionally distinct protein isoforms. Mostly, one cell type is responsible for brain-region specific DIE. However, for fewer genes, multiple cell types influence DIE. Thus, regional identity can, although rarely, override cell-type specificity. Cell types indigenous to one anatomic structure display distinctive DIE, e.g. the choroid plexus epithelium manifests distinct transcription-start-site usage. Spatial transcriptomics and long-read sequencing yield a spatially resolved splicing map. Our methods quantify isoform expression with cell-type and spatial resolution and it contributes to further our understanding of how the brain integrates molecular and cellular complexity.
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Affiliation(s)
- Anoushka Joglekar
- Brain and Mind Research Institute and Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA
| | - Andrey Prjibelski
- Center for Algorithmic Biotechnology, Institute of Translational Biomedicine, St. Petersburg State University, St Petersburg, Russia
| | - Ahmed Mahfouz
- Department of Human Genetics, Leiden University Medical Center, Leiden, 2333 ZC, The Netherlands
- Leiden Computational Biology Center, Leiden University Medical Center, Leiden, 2333 ZC, The Netherlands
- Delft Bioinformatics Lab, Delft University of Technology, Delft, 2628 XE, The Netherlands
| | - Paul Collier
- Brain and Mind Research Institute and Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA
| | - Susan Lin
- Graduate Program in Neuroscience, Weill Cornell Medical College, 1300 York Avenue, New York, NY, 10065, USA
- Cardiovascular Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Anna Katharina Schlusche
- Brain and Mind Research Institute and Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA
| | - Jordan Marrocco
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA
| | | | - Bettina Haase
- The Vertebrate Genomes Lab, The Rockefeller University, New York, NY, USA
| | | | | | | | - Man Ying Wong
- Brain and Mind Research Institute and Appel Alzheimer's Research Institute, Weill Cornell Medicine, New York, NY, USA
| | | | - Simon A Hardwick
- Brain and Mind Research Institute and Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Toby Hunt
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, UK
| | - Qi Wang
- Section of Bioinformatics and Systems Cardiology, University Hospital, 96120, Heidelberg, Germany
| | - Christoph Dieterich
- Section of Bioinformatics and Systems Cardiology, University Hospital, 96120, Heidelberg, Germany
| | | | - Olivier Fedrigo
- The Vertebrate Genomes Lab, The Rockefeller University, New York, NY, USA
| | - Steven A Sloan
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Davide Risso
- Department of Statistical Sciences, University of Padova, Padova, Italy
| | - Erich D Jarvis
- The Vertebrate Genomes Lab, The Rockefeller University, New York, NY, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Paul Flicek
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, UK
| | - Wenjie Luo
- Brain and Mind Research Institute and Appel Alzheimer's Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Geoffrey S Pitt
- Graduate Program in Neuroscience, Weill Cornell Medical College, 1300 York Avenue, New York, NY, 10065, USA
- Cardiovascular Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Adam Frankish
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, UK
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands
| | - M Elizabeth Ross
- Brain and Mind Research Institute and Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA
| | - Hagen U Tilgner
- Brain and Mind Research Institute and Center for Neurogenetics, Weill Cornell Medicine, New York, NY, USA.
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18
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Qu W, Jin H, Chen BP, Liu J, Li R, Guo W, Tian H. CPEB3 regulates neuron-specific alternative splicing and involves neurogenesis gene expression. Aging (Albany NY) 2020; 13:2330-2347. [PMID: 33318303 PMCID: PMC7880327 DOI: 10.18632/aging.202259] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 10/27/2020] [Indexed: 12/17/2022]
Abstract
In the mammalian brain, alternative pre-mRNA splicing is a fundamental mechanism that modifies neuronal function dynamically where secretion of different splice variants regulates neurogenesis, development, pathfinding, maintenance, migration, and synaptogenesis. Sequence-specific RNA-Binding Protein CPEB3 has distinctive isoform-distinct biochemical interactions and neuronal development assembly roles. Nonetheless, the mechanisms moderating splice isoform options remain unclear. To establish the modulatory trend of CPEB3, we cloned and excessively expressed CPEB3 in HT22 cells. We used RNA-seq to analyze CPEB3-regulated alternative splicing on control and CPEB3-overexpressing cells. Consequently, we used iRIP-seq to identify CPEB-binding targets. We additionally validated CPEB3-modulated genes using RT-qPCR. CPEB3 overexpression had insignificant effects on gene expression in HT22 cells. Notably, CPEB3 partially modulated differential gene splicing enhanced in the modulation of neural development, neuron cycle, neurotrophin, synapse, and specific development pathway, implying an alternative splicing regulatory mechanism associated with neurogenesis. Moreover, qRT-PCR verified the CPEB3-modulated transcription of neurogenesis genes LCN2 and NAV2, synaptogenesis gene CYLD, as well as neural development gene JADE1. Herein, we established that CPEB3 is a critical modulator of alternative splicing in neurogenesis, which remarkably enhances the current understanding of the CPEB3 mediated alternative pre-mRNA splicing.
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Affiliation(s)
- Wenrui Qu
- Department of Hand Surgery, The Second Hospital of Jilin University, Changchun, Jilin Province, China
| | - Hongjuan Jin
- Department of Plastic and Reconstructive Surgery, The First Hospital of Jilin University, Changchun, China
| | - Bing-Peng Chen
- Orthopedic Medical Center, The Second Hospital of Jilin University, Changchun, Jilin Province, China
| | - Jun Liu
- Department of Hand Surgery, The Second Hospital of Jilin University, Changchun, Jilin Province, China
| | - Rui Li
- Department of Hand Surgery, The Second Hospital of Jilin University, Changchun, Jilin Province, China
| | - Wenlai Guo
- Department of Hand Surgery, The Second Hospital of Jilin University, Changchun, Jilin Province, China
| | - Heng Tian
- Department of Hand Surgery, The Second Hospital of Jilin University, Changchun, Jilin Province, China
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19
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Mehravar M, Poursani EM. Novel Variant of OCT4, Named OCT4B5, is Highly Expressed in Human Pluripotent Cells. Stem Cell Rev Rep 2020; 17:1068-1073. [PMID: 33241484 DOI: 10.1007/s12015-020-10093-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2020] [Indexed: 10/22/2022]
Abstract
Alternative promoter and alternative splicing are two important mechanisms of gene regulation and protein diversity in different physiological contexts of eukaryotes, especially in stem cells and developmental stages. Pou5f1 gene which codes the stemness marker OCT4, utilizes alternative splicing and promoter mechanisms, which result in generation of multiple spliced variants and subsequently multiple protein isoforms. By far, nine variants of OCT4 (OCT4A, OCT4B, OCT4B1, OCT4B2, OCT4B3, OCT4B4, OCT4C, OCT4C1, and OCT4D) have been introduced. It has been well established that OCT4A plays essential roles in early developmental stages as well as maintenance of stemness in embryonic stem cells (ESCs). However, the roles and functions of other variants and isoforms of OCT4 in biological systems are less appreciated. In this study, we report a new OCT4 variant, designated as OCT4B5. RT-PCR assay on different human cell lines including pluripotent, normal and cancer cells showed that OCT4B5 is expressed at variable level in different cell lines. By semi-quantifying of OCT4B5 expression in pluripotent and differentiated states of NT2 cell lines, we reveal that this variant of OCT4 is highly expressed in undifferentiated state and its expression is down-regulated upon differentiation. Compared to OCT4A which is sharply down-regulated in retinoic acid induced differentiation of NT2 cell line, the expression of OCT4B5 remains at low level in differentiated state. Overall, this study emphasizes the complexity of OCT4 gene expression and regulation in different states of stem cells and physiological contexts. Graphical Abstract.
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Affiliation(s)
- Majid Mehravar
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ensieh M Poursani
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran. .,Hematology/Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran.
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20
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Koterniak B, Pilaka PP, Gracida X, Schneider LM, Pritišanac I, Zhang Y, Calarco JA. Global regulatory features of alternative splicing across tissues and within the nervous system of C. elegans. Genome Res 2020; 30:1766-1780. [PMID: 33127752 PMCID: PMC7706725 DOI: 10.1101/gr.267328.120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 10/28/2020] [Indexed: 12/27/2022]
Abstract
Alternative splicing plays a major role in shaping tissue-specific transcriptomes. Among the broad tissue types present in metazoans, the central nervous system contains some of the highest levels of alternative splicing. Although many documented examples of splicing differences between broad tissue types exist, there remains much to be understood about the splicing factors and the cis sequence elements controlling tissue and neuron subtype-specific splicing patterns. By using translating ribosome affinity purification coupled with deep-sequencing (TRAP-seq) in Caenorhabditis elegans, we have obtained high coverage profiles of ribosome-associated mRNA for three broad tissue classes (nervous system, muscle, and intestine) and two neuronal subtypes (dopaminergic and serotonergic neurons). We have identified hundreds of splice junctions that exhibit distinct splicing patterns between tissue types or within the nervous system. Alternative splicing events differentially regulated between tissues are more often frame-preserving, are more highly conserved across Caenorhabditis species, and are enriched in specific cis regulatory motifs, when compared with other types of exons. By using this information, we have identified a likely mechanism of splicing repression by the RNA-binding protein UNC-75/CELF via interactions with cis elements that overlap a 5′ splice site. Alternatively spliced exons also overlap more frequently with intrinsically disordered peptide regions than constitutive exons. Moreover, regulated exons are often shorter than constitutive exons but are flanked by longer intron sequences. Among these tissue-regulated exons are several highly conserved microexons <27 nt in length. Collectively, our results indicate a rich layer of tissue-specific gene regulation at the level of alternative splicing in C. elegans that parallels the evolutionary forces and constraints observed across metazoa.
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Affiliation(s)
- Bina Koterniak
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Pallavi P Pilaka
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Xicotencatl Gracida
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Lisa-Marie Schneider
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada.,Department of Chemistry, University of Bayreuth, 95447 Bayreuth, Germany
| | - Iva Pritišanac
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada.,Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Yun Zhang
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - John A Calarco
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
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21
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Thalhammer A, Jaudon F, Cingolani LA. Emerging Roles of Activity-Dependent Alternative Splicing in Homeostatic Plasticity. Front Cell Neurosci 2020; 14:104. [PMID: 32477067 PMCID: PMC7235277 DOI: 10.3389/fncel.2020.00104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 04/06/2020] [Indexed: 12/25/2022] Open
Abstract
Homeostatic plasticity refers to the ability of neuronal networks to stabilize their activity in the face of external perturbations. Most forms of homeostatic plasticity ultimately depend on changes in the expression or activity of ion channels and synaptic proteins, which may occur at the gene, transcript, or protein level. The most extensively investigated homeostatic mechanisms entail adaptations in protein function or localization following activity-dependent posttranslational modifications. Numerous studies have also highlighted how homeostatic plasticity can be achieved by adjusting local protein translation at synapses or transcription of specific genes in the nucleus. In comparison, little attention has been devoted to whether and how alternative splicing (AS) of pre-mRNAs underlies some forms of homeostatic plasticity. AS not only expands proteome diversity but also contributes to the spatiotemporal dynamics of mRNA transcripts. Prominent in the brain where it can be regulated by neuronal activity, it is a flexible process, tightly controlled by a multitude of factors. Given its extensive use and versatility in optimizing the function of ion channels and synaptic proteins, we argue that AS is ideally suited to achieve homeostatic control of neuronal output. We support this thesis by reviewing emerging evidence linking AS to various forms of homeostatic plasticity: homeostatic intrinsic plasticity, synaptic scaling, and presynaptic homeostatic plasticity. Further, we highlight the relevance of this connection for brain pathologies.
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Affiliation(s)
- Agnes Thalhammer
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Fanny Jaudon
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Lorenzo A Cingolani
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,Department of Life Sciences, University of Trieste, Trieste, Italy
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22
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Guo Z, Zhu H, Xu W, Wang X, Liu H, Wu Y, Wang M, Chu H, Zhang Z. Alternative splicing related genetic variants contribute to bladder cancer risk. Mol Carcinog 2020; 59:923-929. [PMID: 32339354 DOI: 10.1002/mc.23207] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 04/01/2020] [Accepted: 04/19/2020] [Indexed: 01/20/2023]
Abstract
Emerging evidence has shown that aberrant alternative splicing (AS) events are involved in the carcinogenesis. The association between genetic variants in AS and bladder cancer susceptibility remains to be fully elucidated. We searched for single nucleotide polymorphisms (SNPs) which are located in splicing quantitative trait loci (sQTLs) in bladder cancer through CancerSplicingQTL database and the 1000 Genomes Project. A case-control study including 580 cases and 1,101 controls was conducted to assess the association between the functional genetic variants and bladder cancer risk. Next, we used GTEx, TCGA, and GEO databases conducting sQTL analysis and gene expression differences analysis to evaluate the potential biological function of the candidate SNPs and related genes. We found that SNP rs4383 C>G was remarkably related with the reduced risk of bladder cancer (odds ratio = 0.68, 95% confidence interval = 0.59-0.79, P = 3.91 × 10-7 ). Similar results were obtained in codominant, dominant and recessive model. Stratified analyses revealed that the effect of SNP rs4383 C>G on bladder cancer was more significant in the older subjects (age > 65), female and nonsmokers. sQTL analysis showed that SNP rs4383 was associated with the AS events of its downstream gene MAFF with a splicing event of alternative 5' splice site. The messenger RNA expression of MAFF in bladder tumor tissues was lowered compared with normal tissues. Patients with high expression of MAFF had higher survival rates. These findings indicated that SNP rs4383 related with the AS events of MAFF was associated with bladder cancer risk and could represent a possible biomarker for bladder cancer susceptibility.
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Affiliation(s)
- Zheng Guo
- Department of Environmental Genomics, Jiangsu Key Laboratory of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China.,Department of Genetic Toxicology, The Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Huanhuan Zhu
- Department of Environmental Genomics, Jiangsu Key Laboratory of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China.,Department of Genetic Toxicology, The Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Weidong Xu
- Department of Urology, Yizheng Hospital, Drum Tower Hospital Group of Nanjing, Yizheng, China
| | - Xi Wang
- Department of Environmental Genomics, Jiangsu Key Laboratory of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China.,Department of Genetic Toxicology, The Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Hanting Liu
- Department of Environmental Genomics, Jiangsu Key Laboratory of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China.,Department of Genetic Toxicology, The Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Yanling Wu
- Department of Environmental Genomics, Jiangsu Key Laboratory of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China.,Department of Genetic Toxicology, The Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Meilin Wang
- Department of Environmental Genomics, Jiangsu Key Laboratory of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China.,Department of Genetic Toxicology, The Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Haiyan Chu
- Department of Environmental Genomics, Jiangsu Key Laboratory of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China.,Department of Genetic Toxicology, The Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Zhengdong Zhang
- Department of Environmental Genomics, Jiangsu Key Laboratory of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China.,Department of Genetic Toxicology, The Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
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23
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Che Y, Fu L. Aberrant expression and regulatory network of splicing factor-SRSF3 in tumors. J Cancer 2020; 11:3502-3511. [PMID: 32284746 PMCID: PMC7150454 DOI: 10.7150/jca.42645] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/26/2020] [Indexed: 12/14/2022] Open
Abstract
Alternative splicing facilitates the splicing of precursor RNA into different isoforms. Alternatively spliced transcripts often exhibit antagonistic functions or differential temporal or spatial expression patterns. There is increasing evidence that alternative splicing, especially by the serine-arginine rich (SR) protein family, leads to abnormal expression patterns and is closely related to the development of cancer. SRSF3, also known as SRp20, is a splicing factor. Through alternative splicing, it plays important roles in regulating various biological functions, such as cell cycle, cell proliferation, migration and invasion, under pathological and physiological conditions. Deregulation of SRSF3 is an essential feature of cancers. SRSF3 is also considered a candidate therapeutic target. Therefore, the involvement of abnormal splicing in tumorigenesis and the regulation of splicing factors deserve further analysis and discussion. Here, we summarize the function of SRSF3-regulated alternative transcripts in cancer cell biology at different stages of tumor development and the regulation of SRSF3 in tumorigenesis.
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Affiliation(s)
- Yingying Che
- Institute of Chronic Disease, Qingdao Municipal Hospital, Qingdao University, Qingdao 266000, China
| | - Lin Fu
- Institute of Chronic Disease, Qingdao Municipal Hospital, Qingdao University, Qingdao 266000, China
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24
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David JK, Maden SK, Weeder BR, Thompson RF, Nellore A. Putatively cancer-specific exon-exon junctions are shared across patients and present in developmental and other non-cancer cells. NAR Cancer 2020; 2:zcaa001. [PMID: 34316681 PMCID: PMC8209686 DOI: 10.1093/narcan/zcaa001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 01/06/2020] [Accepted: 01/14/2020] [Indexed: 01/08/2023] Open
Abstract
This study probes the distribution of putatively cancer-specific junctions across a broad set of publicly available non-cancer human RNA sequencing (RNA-seq) datasets. We compared cancer and non-cancer RNA-seq data from The Cancer Genome Atlas (TCGA), the Genotype-Tissue Expression (GTEx) Project and the Sequence Read Archive. We found that (i) averaging across cancer types, 80.6% of exon–exon junctions thought to be cancer-specific based on comparison with tissue-matched samples (σ = 13.0%) are in fact present in other adult non-cancer tissues throughout the body; (ii) 30.8% of junctions not present in any GTEx or TCGA normal tissues are shared by multiple samples within at least one cancer type cohort, and 87.4% of these distinguish between different cancer types; and (iii) many of these junctions not found in GTEx or TCGA normal tissues (15.4% on average, σ = 2.4%) are also found in embryological and other developmentally associated cells. These findings refine the meaning of RNA splicing event novelty, particularly with respect to the human neoepitope repertoire. Ultimately, cancer-specific exon–exon junctions may have a substantial causal relationship with the biology of disease.
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Affiliation(s)
- Julianne K David
- Computational Biology Program, Oregon Health & Science University, Portland, OR 97239, USA.,Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA
| | - Sean K Maden
- Computational Biology Program, Oregon Health & Science University, Portland, OR 97239, USA.,Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA
| | - Benjamin R Weeder
- Computational Biology Program, Oregon Health & Science University, Portland, OR 97239, USA.,Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA
| | - Reid F Thompson
- Computational Biology Program, Oregon Health & Science University, Portland, OR 97239, USA.,Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA.,Department of Radiation Medicine, Oregon Health & Science University, Portland, OR 97239, USA.,Portland VA Research Foundation, Portland, OR 97239, USA.,Department of Medical Informatics and Clinical Epidemiology, Oregon Health & Science University, Portland, OR 97239, USA.,Division of Hospital and Specialty Medicine, VA Portland Healthcare System, Portland, OR 97239, USA.,Cancer Early Detection Advanced Research Center, Oregon Health & Science University, Portland, OR 97239, USA
| | - Abhinav Nellore
- Computational Biology Program, Oregon Health & Science University, Portland, OR 97239, USA.,Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA.,Department of Surgery, Oregon Health & Science University, Portland, OR 97239, USA
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25
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Kober KM, Lee MC, Olshen A, Conley YP, Sirota M, Keiser M, Hammer MJ, Abrams G, Schumacher M, Levine JD, Miaskowski C. Differential methylation and expression of genes in the hypoxia-inducible factor 1 signaling pathway are associated with paclitaxel-induced peripheral neuropathy in breast cancer survivors and with preclinical models of chemotherapy-induced neuropathic pain. Mol Pain 2020; 16:1744806920936502. [PMID: 32586194 PMCID: PMC7322824 DOI: 10.1177/1744806920936502] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/26/2020] [Accepted: 06/01/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Paclitaxel is an important chemotherapeutic agent for the treatment of breast cancer. Paclitaxel-induced peripheral neuropathy (PIPN) is a major dose-limiting toxicity that can persist into survivorship. While not all survivors develop PIPN, for those who do, it has a substantial negative impact on their functional status and quality of life. No interventions are available to treat PIPN. In our previous studies, we identified that the HIF-1 signaling pathway (H1SP) was perturbed between breast cancer survivors with and without PIPN. Preclinical studies suggest that the H1SP is involved in the development of bortezomib-induced and diabetic peripheral neuropathy, and sciatic nerve injury. The purpose of this study was to identify H1SP genes that have both differential methylation and differential gene expression between breast cancer survivors with and without PIPN. METHODS A multi-staged integrated analysis was performed. In peripheral blood, methylation was assayed using microarray and gene expression was assayed using RNA-seq. Candidate genes in the H1SP having both differentially methylation and differential expression were identified between survivors who received paclitaxel and did (n = 25) and did not (n = 25) develop PIPN. Then, candidate genes were evaluated for differential methylation and differential expression in public data sets of preclinical models of PIPN and sciatic nerve injury. RESULTS Eight candidate genes were identified as both differential methylation and differential expression in survivors. Of the eight homologs identified, one was found to be differential expression in both PIPN and "normal" mice dorsal root ganglia; three were differential methylation in sciatic nerve injury versus sham rats in both pre-frontal cortex and T-cells; and two were differential methylation in sciatic nerve injury versus sham rats in the pre-frontal cortex. CONCLUSIONS This study is the first to evaluate for methylation in cancer survivors with chronic PIPN. The findings provide evidence that the expression of H1SP genes associated with chronic PIPN in cancer survivors may be regulated by epigenetic mechanisms and suggests genes for validation as potential therapeutic targets.
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Affiliation(s)
- Kord M Kober
- School of Nursing, University of
California, San Francisco, CA, USA
- Helen Diller Family Comprehensive
Cancer Center, University of California, San Francisco, CA, USA
- Bakar Computational Health Sciences
Institute, University of California, San Francisco, CA, USA
| | - Man-Cheung Lee
- School of Medicine, University of
California, San Francisco, CA, USA
| | - Adam Olshen
- Helen Diller Family Comprehensive
Cancer Center, University of California, San Francisco, CA, USA
- Department of Epidemiology and
Biostatistics, University of California, San Francisco, CA, USA
| | - Yvette P Conley
- School of Nursing,
University
of Pittsburgh, Pittsburgh, PA, USA
| | - Marina Sirota
- Bakar Computational Health Sciences
Institute, University of California, San Francisco, CA, USA
- School of Medicine, University of
California, San Francisco, CA, USA
| | - Michael Keiser
- Bakar Computational Health Sciences
Institute, University of California, San Francisco, CA, USA
- School of Medicine, University of
California, San Francisco, CA, USA
- Institute for Neurodegenerative
Diseases, University of California, San Francisco, CA, USA
| | - Marilyn J Hammer
- Phyllis F. Cantor Center,
Dana-Farber Cancer Institute, Boston, MA, USA
| | - Gary Abrams
- School of Medicine, University of
California, San Francisco, CA, USA
| | - Mark Schumacher
- School of Medicine, University of
California, San Francisco, CA, USA
| | - Jon D Levine
- School of Medicine, University of
California, San Francisco, CA, USA
| | - Christine Miaskowski
- School of Nursing, University of
California, San Francisco, CA, USA
- Helen Diller Family Comprehensive
Cancer Center, University of California, San Francisco, CA, USA
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26
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Thompson M, Bixby R, Dalton R, Vandenburg A, Calarco JA, Norris AD. Splicing in a single neuron is coordinately controlled by RNA binding proteins and transcription factors. eLife 2019; 8:46726. [PMID: 31322498 PMCID: PMC6641836 DOI: 10.7554/elife.46726] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 06/20/2019] [Indexed: 12/22/2022] Open
Abstract
Single-cell transcriptomes are established by transcription factors (TFs), which determine a cell's gene-expression complement. Post-transcriptional regulation of single-cell transcriptomes, and the RNA binding proteins (RBPs) responsible, are more technically challenging to determine, and combinatorial TF-RBP coordination of single-cell transcriptomes remains unexplored. We used fluorescent reporters to visualize alternative splicing in single Caenorhabditis elegans neurons, identifying complex splicing patterns in the neuronal kinase sad-1. Most neurons express both isoforms, but the ALM mechanosensory neuron expresses only the exon-included isoform, while its developmental sister cell the BDU neuron expresses only the exon-skipped isoform. A cascade of three cell-specific TFs and two RBPs are combinatorially required for sad-1 exon inclusion. Mechanistically, TFs combinatorially ensure expression of RBPs, which interact with sad-1 pre-mRNA. Thus a combinatorial TF-RBP code controls single-neuron sad-1 splicing. Additionally, we find ‘phenotypic convergence,’ previously observed for TFs, also applies to RBPs: different RBP combinations generate similar splicing outcomes in different neurons. All the cells in the human nervous system contain the same genetic information, and yet there are many kinds of neurons, each with different features and roles in the body. Proteins known as transcription factors help to establish this diversity by switching on different genes in different types of cells. A mechanism known as RNA splicing, which is regulated by RNA binding proteins, can also provide another layer of regulation. When a gene is switched on, a faithful copy of its sequence is produced in the form of an RNA molecule, which will then be ‘read’ to create a protein. However, the RNA molecules may first be processed to create templates that can differ between cell types: this means that a single gene can code for slightly different proteins, some of them specific to a given cell type. Yet, very little is known about how RNA splicing can generate more diversity in the nervous system. To investigate, Thompson et al. developed a fluorescent reporter system that helped them track how the RNA of a gene called sad-1 is spliced in individual neurons of the worm Caenorhabditis elegans. This showed that sad-1 was turned on in all neurons, but the particular spliced versions varied widely between different types of nerve cells. Additional experiments combined old school and cutting-edge genetics technics such as CRISPR/Cas9 to identify the proteins that control the splicing of sad-1 in different kinds of neurons. Despite not directly participating in RNA splicing, a number of transcription factors were shown to be involved. These molecular switches were turning on genes that code for RNA binding proteins differently between types of neurons, which in turn led sad-1 to be spliced according to neuron-specific patterns. The findings by Thompson et al. could provide some insight into how mammals can establish many types of neurons; however, a technical hurdle stands in the way of this line of research, as it is still difficult to detect splicing in single neurons in these species.
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Affiliation(s)
- Morgan Thompson
- Biological Sciences, Southern Methodist University, Dallas, United States
| | - Ryan Bixby
- Biological Sciences, Southern Methodist University, Dallas, United States
| | - Robert Dalton
- Biological Sciences, Southern Methodist University, Dallas, United States
| | - Alexa Vandenburg
- Biological Sciences, Southern Methodist University, Dallas, United States
| | - John A Calarco
- Cell & Systems Biology, University of Toronto, Toronto, Canada
| | - Adam D Norris
- Biological Sciences, Southern Methodist University, Dallas, United States
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27
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Quesnel-Vallières M, Weatheritt RJ, Cordes SP, Blencowe BJ. Autism spectrum disorder: insights into convergent mechanisms from transcriptomics. Nat Rev Genet 2018; 20:51-63. [DOI: 10.1038/s41576-018-0066-2] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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28
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Wang Q, Abruzzi KC, Rosbash M, Rio DC. Striking circadian neuron diversity and cycling of Drosophila alternative splicing. eLife 2018; 7:35618. [PMID: 29863472 PMCID: PMC6025963 DOI: 10.7554/elife.35618] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/31/2018] [Indexed: 11/13/2022] Open
Abstract
Although alternative pre-mRNA splicing (AS) significantly diversifies the neuronal proteome, the extent of AS is still unknown due in part to the large number of diverse cell types in the brain. To address this complexity issue, we used an annotation-free computational method to analyze and compare the AS profiles between small specific groups of Drosophila circadian neurons. The method, the Junction Usage Model (JUM), allows the comprehensive profiling of both known and novel AS events from specific RNA-seq libraries. The results show that many diverse and novel pre-mRNA isoforms are preferentially expressed in one class of clock neuron and also absent from the more standard Drosophila head RNA preparation. These AS events are enriched in potassium channels important for neuronal firing, and there are also cycling isoforms with no detectable underlying transcriptional oscillations. The results suggest massive AS regulation in the brain that is also likely important for circadian regulation.
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Affiliation(s)
- Qingqing Wang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Center for RNA Systems Biology (CRSB), University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, United States
| | - Katharine C Abruzzi
- Department of Biology, Howard Hughes Medical Institute, Brandeis University, Waltham, United States.,National Center for Behavior Genomics, Brandeis University, Waltham, United States
| | - Michael Rosbash
- Department of Biology, Howard Hughes Medical Institute, Brandeis University, Waltham, United States.,National Center for Behavior Genomics, Brandeis University, Waltham, United States
| | - Donald C Rio
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Center for RNA Systems Biology (CRSB), University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, United States
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29
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Su CH, D D, Tarn WY. Alternative Splicing in Neurogenesis and Brain Development. Front Mol Biosci 2018; 5:12. [PMID: 29484299 PMCID: PMC5816070 DOI: 10.3389/fmolb.2018.00012] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/25/2018] [Indexed: 12/20/2022] Open
Abstract
Alternative splicing of precursor mRNA is an important mechanism that increases transcriptomic and proteomic diversity and also post-transcriptionally regulates mRNA levels. Alternative splicing occurs at high frequency in brain tissues and contributes to every step of nervous system development, including cell-fate decisions, neuronal migration, axon guidance, and synaptogenesis. Genetic manipulation and RNA sequencing have provided insights into the molecular mechanisms underlying the effects of alternative splicing in stem cell self-renewal and neuronal fate specification. Timely expression and perhaps post-translational modification of neuron-specific splicing regulators play important roles in neuronal development. Alternative splicing of many key transcription regulators or epigenetic factors reprograms the transcriptome and hence contributes to stem cell fate determination. During neuronal differentiation, alternative splicing also modulates signaling activity, centriolar dynamics, and metabolic pathways. Moreover, alternative splicing impacts cortical lamination and neuronal development and function. In this review, we focus on recent progress toward understanding the contributions of alternative splicing to neurogenesis and brain development, which has shed light on how splicing defects may cause brain disorders and diseases.
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Affiliation(s)
- Chun-Hao Su
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Dhananjaya D
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan
| | - Woan-Yuh Tarn
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan
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30
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Tan JH, Fraser AG. The combinatorial control of alternative splicing in C. elegans. PLoS Genet 2017; 13:e1007033. [PMID: 29121637 PMCID: PMC5697891 DOI: 10.1371/journal.pgen.1007033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 11/21/2017] [Accepted: 09/19/2017] [Indexed: 12/31/2022] Open
Abstract
Normal development requires the right splice variants to be made in the right tissues at the right time. The core splicing machinery is engaged in all splicing events, but which precise splice variant is made requires the choice between alternative splice sites—for this to occur, a set of splicing factors (SFs) must recognize and bind to short RNA motifs in the pre-mRNA. In C. elegans, there is known to be extensive variation in splicing patterns across development, but little is known about the targets of each SF or how multiple SFs combine to regulate splicing. Here we combine RNA-seq with in vitro binding assays to study how 4 different C. elegans SFs, ASD-1, FOX-1, MEC-8, and EXC-7, regulate splicing. The 4 SFs chosen all have well-characterised biology and well-studied loss-of-function genetic alleles, and all contain RRM domains. Intriguingly, while the SFs we examined have varied roles in C. elegans development, they show an unexpectedly high overlap in their targets. We also find that binding sites for these SFs occur on the same pre-mRNAs more frequently than expected suggesting extensive combinatorial control of splicing. We confirm that regulation of splicing by multiple SFs is often combinatorial and show that this is functionally significant. We also find that SFs appear to combine to affect splicing in two modes—they either bind in close proximity within the same intron or they appear to bind to separate regions of the intron in a conserved order. Finally, we find that the genes whose splicing are regulated by multiple SFs are highly enriched for genes involved in the cytoskeleton and in ion channels that are key for neurotransmission. Together, this shows that specific classes of genes have complex combinatorial regulation of splicing and that this combinatorial regulation is critical for normal development to occur. Alternative splicing (AS) is a highly regulated process that is crucial for normal development. It requires the core splicing machinery, but the specific choice of splice site during AS is controlled by splicing factors (SFs) such as ELAV or RBFOX proteins that bind to specific sequences in pre-mRNAs to regulate usage of different splice sites. AS varies across the C. elegans life cycle and here we study how diverse SFs combine to regulate AS during C. elegans development. We selected 4 RRM-containing SFs that are all well studied and that have well-characterised loss-of-function genetic alleles. We find that these SFs regulate many of the same targets, and that combinatorial interactions between these SFs affect both individual splicing events and organism-level phenotypes including specific effects on the neuromuscular system. We further show that SFs combine to regulate splicing of an individual pre-mRNA in two distinct modes—either by binding in close proximity or by binding in a defined order on the pre-mRNA. Finally, we find that the genes whose splicing are most likely to be regulated by multiple SFs are genes that are required for the proper function of the neuromuscular system. These genes are also most likely to have changing AS patterns across development, suggesting that their splicing regulation is highly complex and developmentally regulated. Taken together, our data show that the precise splice variant expressed at any point in development is often the outcome of regulation by multiple SFs.
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Affiliation(s)
- June H. Tan
- The Donnelly Centre, University of Toronto, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON, Canada
| | - Andrew G. Fraser
- The Donnelly Centre, University of Toronto, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON, Canada
- * E-mail:
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31
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Huang D, Fletcher S, Wilton SD, Palmer N, McLenachan S, Mackey DA, Chen FK. Inherited Retinal Disease Therapies Targeting Precursor Messenger Ribonucleic Acid. Vision (Basel) 2017; 1:vision1030022. [PMID: 31740647 PMCID: PMC6836112 DOI: 10.3390/vision1030022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 07/24/2017] [Accepted: 08/24/2017] [Indexed: 02/07/2023] Open
Abstract
Inherited retinal diseases are an extremely diverse group of genetically and phenotypically heterogeneous conditions characterized by variable maturation of retinal development, impairment of photoreceptor cell function and gradual loss of photoreceptor cells and vision. Significant progress has been made over the last two decades in identifying the many genes implicated in inherited retinal diseases and developing novel therapies to address the underlying genetic defects. Approximately one-quarter of exonic mutations related to human inherited diseases are likely to induce aberrant splicing products, providing opportunities for the development of novel therapeutics that target splicing processes. The feasibility of antisense oligomer mediated splice intervention to treat inherited diseases has been demonstrated in vitro, in vivo and in clinical trials. In this review, we will discuss therapeutic approaches to treat inherited retinal disease, including strategies to correct splicing and modify exon selection at the level of pre-mRNA. The challenges of clinical translation of this class of emerging therapeutics will also be discussed.
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Affiliation(s)
- Di Huang
- Molecular Therapy Laboratory, Murdoch University, Murdoch 6150, Australia
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Nedlands 6009, Australia
- Perron Institute, 4th Floor A Block, Queen Elizabeth II Medical Centre, Verdun Street, Nedlands 6009, Australia
| | - Sue Fletcher
- Molecular Therapy Laboratory, Murdoch University, Murdoch 6150, Australia
- Perron Institute, 4th Floor A Block, Queen Elizabeth II Medical Centre, Verdun Street, Nedlands 6009, Australia
| | - Steve D. Wilton
- Molecular Therapy Laboratory, Murdoch University, Murdoch 6150, Australia
- Perron Institute, 4th Floor A Block, Queen Elizabeth II Medical Centre, Verdun Street, Nedlands 6009, Australia
| | - Norman Palmer
- Perron Institute, 4th Floor A Block, Queen Elizabeth II Medical Centre, Verdun Street, Nedlands 6009, Australia
| | - Samuel McLenachan
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Nedlands 6009, Australia
| | - David A. Mackey
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Nedlands 6009, Australia
| | - Fred K. Chen
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Nedlands 6009, Australia
- Department of Ophthalmology, Royal Perth Hospital, Perth 6000, Australia
- Correspondence: ; Tel.: +61-8-9381-0817
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Sharangdhar T, Sugimoto Y, Heraud-Farlow J, Fernández-Moya SM, Ehses J, Ruiz de Los Mozos I, Ule J, Kiebler MA. A retained intron in the 3'-UTR of Calm3 mRNA mediates its Staufen2- and activity-dependent localization to neuronal dendrites. EMBO Rep 2017; 18:1762-1774. [PMID: 28765142 DOI: 10.15252/embr.201744334] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/30/2017] [Accepted: 07/05/2017] [Indexed: 11/09/2022] Open
Abstract
Dendritic localization and hence local mRNA translation contributes to synaptic plasticity in neurons. Staufen2 (Stau2) is a well-known neuronal double-stranded RNA-binding protein (dsRBP) that has been implicated in dendritic mRNA localization. The specificity of Stau2 binding to its target mRNAs remains elusive. Using individual-nucleotide resolution CLIP (iCLIP), we identified significantly enriched Stau2 binding to the 3'-UTRs of 356 transcripts. In 28 (7.9%) of those, binding occurred to a retained intron in their 3'-UTR The strongest bound 3'-UTR intron was present in the longest isoform of Calmodulin 3 (Calm3L ) mRNA Calm3L 3'-UTR contains six Stau2 crosslink clusters, four of which are in this retained 3'-UTR intron. The Calm3L mRNA localized to neuronal dendrites, while lack of the 3'-UTR intron impaired its dendritic localization. Importantly, Stau2 mediates this dendritic localization via the 3'-UTR intron, without affecting its stability. Also, NMDA-mediated synaptic activity specifically promoted the dendritic mRNA localization of the Calm3L isoform, while inhibition of synaptic activity reduced it substantially. Together, our results identify the retained intron as a critical element in recruiting Stau2, which then allows for the localization of Calm3L mRNA to distal dendrites.
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Affiliation(s)
| | - Yoichiro Sugimoto
- Department of Molecular Neuroscience, University College London Institute of Neurology, London, UK.,The Francis Crick Institute, London, UK
| | | | | | - Janina Ehses
- Division of Cell Biology, Biomedical Center, LMU Munich, Martinsried, Germany
| | - Igor Ruiz de Los Mozos
- Department of Molecular Neuroscience, University College London Institute of Neurology, London, UK.,The Francis Crick Institute, London, UK
| | - Jernej Ule
- Department of Molecular Neuroscience, University College London Institute of Neurology, London, UK.,The Francis Crick Institute, London, UK
| | - Michael A Kiebler
- Division of Cell Biology, Biomedical Center, LMU Munich, Martinsried, Germany
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Climente-González H, Porta-Pardo E, Godzik A, Eyras E. The Functional Impact of Alternative Splicing in Cancer. Cell Rep 2017; 20:2215-2226. [DOI: 10.1016/j.celrep.2017.08.012] [Citation(s) in RCA: 355] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 07/15/2017] [Accepted: 07/26/2017] [Indexed: 12/29/2022] Open
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Oegema R, Baillat D, Schot R, van Unen LM, Brooks A, Kia SK, Hoogeboom AJM, Xia Z, Li W, Cesaroni M, Lequin MH, van Slegtenhorst M, Dobyns WB, de Coo IFM, Verheijen FW, Kremer A, van der Spek PJ, Heijsman D, Wagner EJ, Fornerod M, Mancini GMS. Human mutations in integrator complex subunits link transcriptome integrity to brain development. PLoS Genet 2017; 13:e1006809. [PMID: 28542170 PMCID: PMC5466333 DOI: 10.1371/journal.pgen.1006809] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 06/09/2017] [Accepted: 05/09/2017] [Indexed: 02/06/2023] Open
Abstract
Integrator is an RNA polymerase II (RNAPII)-associated complex that was recently identified to have a broad role in both RNA processing and transcription regulation. Importantly, its role in human development and disease is so far largely unexplored. Here, we provide evidence that biallelic Integrator Complex Subunit 1 (INTS1) and Subunit 8 (INTS8) gene mutations are associated with rare recessive human neurodevelopmental syndromes. Three unrelated individuals of Dutch ancestry showed the same homozygous truncating INTS1 mutation. Three siblings harboured compound heterozygous INTS8 mutations. Shared features by these six individuals are severe neurodevelopmental delay and a distinctive appearance. The INTS8 family in addition presented with neuronal migration defects (periventricular nodular heterotopia). We show that the first INTS8 mutation, a nine base-pair deletion, leads to a protein that disrupts INT complex stability, while the second missense mutation introduces an alternative splice site leading to an unstable messenger. Cells from patients with INTS8 mutations show increased levels of unprocessed UsnRNA, compatible with the INT function in the 3’-end maturation of UsnRNA, and display significant disruptions in gene expression and RNA processing. Finally, the introduction of the INTS8 deletion mutation in P19 cells using genome editing alters gene expression throughout the course of retinoic acid-induced neural differentiation. Altogether, our results confirm the essential role of Integrator to transcriptome integrity and point to the requirement of the Integrator complex in human brain development. Neurodevelopmental disorders often have a genetic cause, however the genes and the underlying mechanisms that are involved are increasingly diverse, pointing to the complexity of brain development. For normal cell function and in general for normal development, mechanisms that regulate gene transcription into mRNA are of outermost importance as proper spatial and temporal expression of key developmentally regulated transcripts is essential. The Integrator complex was recently identified to have a broad role in both RNA processing and transcription regulation. This complex is assembled from at least 14 different subunits and several animal studies have pointed to an important role in development. Nevertheless, studies directly demonstrating the relevance of this complex in human health and development have been lacking until now. We show here that mutations in the Integrator Complex Subunit 1 gene (INTS1) and Subunit 8 gene (INTS8) cause a severe neurodevelopmental syndrome, characterized by profound intellectual disability, epilepsy, spasticity, facial and limb dysmorphism and subtle structural brain abnormalities. While the role of the Integrator complex in neuronal migration has recently been established, we provide evidence that INTS8 mutations lead in vitro to instability of the complex and impaired function. In patients cultured fibroblasts we found evidence for abnormalities in mRNA transcription and processing. In addition, introduction of INTS8 mutations in an in vitro model of retinoic acid-induced neuronal differentiation results also in transcription alterations. Altogether our results suggest an evolutionary conserved requirement of INTS1 and INTS8 in brain development.
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Affiliation(s)
- Renske Oegema
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - David Baillat
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston TX, United States of America
| | - Rachel Schot
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Leontine M. van Unen
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Alice Brooks
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Sima Kheradmand Kia
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | | | - Zheng Xia
- Division of Biostatistics, Dan L Duncan Cancer Center, Baylor College of Medicine, Houston, TX, United States of America
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States of America
| | - Wei Li
- Division of Biostatistics, Dan L Duncan Cancer Center, Baylor College of Medicine, Houston, TX, United States of America
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States of America
| | - Matteo Cesaroni
- The Fels Institute, Temple University School of Medicine, Philadelphia, PA, United States of America
| | - Maarten H. Lequin
- Department of Pediatric Radiology, Erasmus MC- Sophia, University Medical Center Rotterdam, The Netherlands
| | - Marjon van Slegtenhorst
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - William B. Dobyns
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
| | - Irenaeus F. M. de Coo
- Department of Neurology, Erasmus MC- Sophia, University Medical Center Rotterdam, The Netherlands
| | - Frans W. Verheijen
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Andreas Kremer
- Department of Bioinformatics, Erasmus MC, University Medical Center Rotterdam, The Netherlands
| | - Peter J. van der Spek
- Department of Bioinformatics, Erasmus MC, University Medical Center Rotterdam, The Netherlands
| | - Daphne Heijsman
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
- Department of Bioinformatics, Erasmus MC, University Medical Center Rotterdam, The Netherlands
| | - Eric J. Wagner
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston TX, United States of America
- * E-mail: (GMSM); (EJW)
| | - Maarten Fornerod
- Department of Pediatric Oncology and Biochemistry, Erasmus MC, University Medical Center Rotterdam, The Netherlands
| | - Grazia M. S. Mancini
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
- * E-mail: (GMSM); (EJW)
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Thomas-Jinu S, Gordon PM, Fielding T, Taylor R, Smith BN, Snowden V, Blanc E, Vance C, Topp S, Wong CH, Bielen H, Williams KL, McCann EP, Nicholson GA, Pan-Vazquez A, Fox AH, Bond CS, Talbot WS, Blair IP, Shaw CE, Houart C. Non-nuclear Pool of Splicing Factor SFPQ Regulates Axonal Transcripts Required for Normal Motor Development. Neuron 2017; 94:322-336.e5. [PMID: 28392072 PMCID: PMC5405110 DOI: 10.1016/j.neuron.2017.03.026] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 01/02/2017] [Accepted: 03/17/2017] [Indexed: 12/12/2022]
Abstract
Recent progress revealed the complexity of RNA processing and its association to human disorders. Here, we unveil a new facet of this complexity. Complete loss of function of the ubiquitous splicing factor SFPQ affects zebrafish motoneuron differentiation cell autonomously. In addition to its nuclear localization, the protein unexpectedly localizes to motor axons. The cytosolic version of SFPQ abolishes motor axonal defects, rescuing key transcripts, and restores motility in the paralyzed sfpq null mutants, indicating a non-nuclear processing role in motor axons. Novel variants affecting the conserved coiled-coil domain, so far exclusively found in fALS exomes, specifically affect the ability of SFPQ to localize in axons. They broadly rescue morphology and motility in the zebrafish mutant, but alter motor axon morphology, demonstrating functional requirement for axonal SFPQ. Altogether, we uncover the axonal function of the splicing factor SFPQ in motor development and highlight the importance of the coiled-coil domain in this process. Video Abstract
SFPQ splicing factor is present in motor axons Non-nuclear SFPQ is able to drive axon maturation and connectivity Loss of axonal SFPQ affects axonal morphology Coiled-coil domain of the protein is important for non-nuclear localization
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Affiliation(s)
- Swapna Thomas-Jinu
- Centre for Developmental Neurobiology and MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Patricia M Gordon
- Centre for Developmental Neurobiology and MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Triona Fielding
- Centre for Developmental Neurobiology and MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Richard Taylor
- Centre for Developmental Neurobiology and MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Bradley N Smith
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London SE5 8AF, UK
| | - Victoria Snowden
- Centre for Developmental Neurobiology and MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Eric Blanc
- Centre for Developmental Neurobiology and MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Caroline Vance
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London SE5 8AF, UK
| | - Simon Topp
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London SE5 8AF, UK
| | - Chun-Hao Wong
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London SE5 8AF, UK
| | - Holger Bielen
- Centre for Developmental Neurobiology and MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Kelly L Williams
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Emily P McCann
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Garth A Nicholson
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia; ANZAC Research Institute, University of Sydney, Concord Hospital, Sydney, NSW 2139, Australia
| | - Alejandro Pan-Vazquez
- Centre for Developmental Neurobiology and MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Archa H Fox
- School of Anatomy, Physiology, and Human Biology, University of Western Australia, Crawley, WA 6009, Australia; Harry Perkins Institute for Medical Research, QEII Medical Centre, Nedlands, WA 6009, Australia; Centre for Medical Research, University of Western Australia, Crawley, WA 6009, Australia
| | - Charles S Bond
- School of Chemistry and Biochemistry, University of Western Australia, Crawley, WA 6009, Australia
| | - William S Talbot
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ian P Blair
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Christopher E Shaw
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London SE5 8AF, UK
| | - Corinne Houart
- Centre for Developmental Neurobiology and MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK.
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Gallego-Paez LM, Bordone MC, Leote AC, Saraiva-Agostinho N, Ascensão-Ferreira M, Barbosa-Morais NL. Alternative splicing: the pledge, the turn, and the prestige : The key role of alternative splicing in human biological systems. Hum Genet 2017; 136:1015-1042. [PMID: 28374191 PMCID: PMC5602094 DOI: 10.1007/s00439-017-1790-y] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/25/2017] [Indexed: 02/06/2023]
Abstract
Alternative pre-mRNA splicing is a tightly controlled process conducted by the spliceosome, with the assistance of several regulators, resulting in the expression of different transcript isoforms from the same gene and increasing both transcriptome and proteome complexity. The differences between alternative isoforms may be subtle but enough to change the function or localization of the translated proteins. A fine control of the isoform balance is, therefore, needed throughout developmental stages and adult tissues or physiological conditions and it does not come as a surprise that several diseases are caused by its deregulation. In this review, we aim to bring the splicing machinery on stage and raise the curtain on its mechanisms and regulation throughout several systems and tissues of the human body, from neurodevelopment to the interactions with the human microbiome. We discuss, on one hand, the essential role of alternative splicing in assuring tissue function, diversity, and swiftness of response in these systems or tissues, and on the other hand, what goes wrong when its regulatory mechanisms fail. We also focus on the possibilities that splicing modulation therapies open for the future of personalized medicine, along with the leading techniques in this field. The final act of the spliceosome, however, is yet to be fully revealed, as more knowledge is needed regarding the complex regulatory network that coordinates alternative splicing and how its dysfunction leads to disease.
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Affiliation(s)
- L M Gallego-Paez
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - M C Bordone
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - A C Leote
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - N Saraiva-Agostinho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - M Ascensão-Ferreira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - N L Barbosa-Morais
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
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37
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Zhou LT, Ye SH, Yang HX, Zhou YT, Zhao QH, Sun WW, Gao MM, Yi YH, Long YS. A novel role of fragile X mental retardation protein in pre-mRNA alternative splicing through RNA-binding protein 14. Neuroscience 2017; 349:64-75. [PMID: 28257890 DOI: 10.1016/j.neuroscience.2017.02.044] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 02/16/2017] [Accepted: 02/20/2017] [Indexed: 02/08/2023]
Abstract
Fragile X mental retardation protein (FMRP), an important RNA-binding protein responsible for fragile X syndrome, is involved in posttranscriptional control of gene expression that links with brain development and synaptic functions. Here, we reveal a novel role of FMRP in pre-mRNA alternative splicing, a general event of posttranscriptional regulation. Using co-immunoprecipitation and immunofluorescence assays, we identified that FMRP interacts with an alternative-splicing-associated protein RNA-binding protein 14 (RBM14) in a RNA-dependent fashion, and the two proteins partially colocalize in the nuclei of hippocampal neurons. We show that the relative skipping/inclusion ratio of the micro-exon L in the Protrudin gene and exon 10 in the Tau gene decreased in the hippocampus of Fmr1 knockout (KO) mice. Knockdown of either FMRP or RBM14 alters the relative skipping/inclusion ratio of Protrudin and Tau in cultured Neuro-2a cells, similar to that in the Fmr1 KO mice. Furthermore, overexpression of FMRP leads to an opposite pattern of the splicing, which can be offset by RBM14 knockdown. RNA immunoprecipitation assays indicate that FMRP promotes RBM14's binding to the mRNA targets. In addition, overexpression of the long form of Protrudin or the short form of Tau promotes protrusion growth of the retinoic acid-treated, neuronal-differentiated Neuro-2a cells. Together, these data suggest a novel function of FMRP in the regulation of pre-mRNA alternative splicing through RBM14 that may be associated with normal brain function and FMRP-related neurological disorders.
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Affiliation(s)
- Lin-Tao Zhou
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Shun-Hua Ye
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Hai-Xuan Yang
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Yong-Ting Zhou
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Qi-Hua Zhao
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Wei-Wen Sun
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Mei-Mei Gao
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Yong-Hong Yi
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China; Department of Neurology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China.
| | - Yue-Sheng Long
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China.
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Developmental pruning of excitatory synaptic inputs to parvalbumin interneurons in monkey prefrontal cortex. Proc Natl Acad Sci U S A 2017; 114:E629-E637. [PMID: 28074037 DOI: 10.1073/pnas.1610077114] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Working memory requires efficient excitatory drive to parvalbumin-positive (PV) interneurons in the primate dorsolateral prefrontal cortex (DLPFC). Developmental pruning eliminates superfluous excitatory inputs, suggesting that working memory maturation during adolescence requires pruning of excitatory inputs to PV interneurons. Therefore, we tested the hypothesis that excitatory synapses on PV interneurons are pruned during adolescence. The density of excitatory synapses, defined by overlapping vesicular glutamate transporter 1-positive (VGlut1+) and postsynaptic density 95-positive (PSD95+) puncta, on PV interneurons was lower in postpubertal relative to prepubertal monkeys. In contrast, puncta levels of VGlut1 and PSD95 proteins were higher in postpubertal monkeys and positively predicted activity-dependent PV levels, suggesting a greater strength of the remaining synapses after pruning. Because excitatory synapse number on PV interneurons is regulated by erb-b2 receptor tyrosine kinase 4 (ErbB4), whose function is influenced by alternative splicing, we tested the hypothesis that pruning of excitatory synapses on PV interneurons is associated with developmental shifts in ErbB4 expression and/or splicing. Pan-ErbB4 expression did not change, whereas the minor-to-major splice variant ratios increased with age. In cell culture, the major, but not the minor, variant increased excitatory synapse number on PV interneurons and displayed greater kinase activity than the minor variant, suggesting that the effect of ErbB4 signaling in PV interneurons is mediated by alternative splicing. Supporting this interpretation, in monkey DLPFC, higher minor-to-major variant ratios predicted lower PSD95+ puncta density on PV interneurons. Together, our findings suggest that ErbB4 splicing may regulate the pruning of excitatory synapses on PV interneurons during adolescence.
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Wang C, Szaro BG. Post-transcriptional regulation mediated by specific neurofilament introns in vivo. J Cell Sci 2016; 129:1500-11. [PMID: 26906423 DOI: 10.1242/jcs.185199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/17/2016] [Indexed: 11/20/2022] Open
Abstract
Neurons regulate genes post-transcriptionally to coordinate the supply of cytoskeletal proteins, such as the medium neurofilament (NEFM), with demand for structural materials in response to extracellular cues encountered by developing axons. By using a method for evaluating functionality of cis-regulatory gene elements in vivo through plasmid injection into Xenopus embryos, we discovered that splicing of a specific nefm intron was required for robust transgene expression, regardless of promoter or cell type. Transgenes utilizing the nefm 3'-UTR but substituting other nefm introns expressed little or no protein owing to defects in handling of the messenger (m)RNA as opposed to transcription or splicing. Post-transcriptional events at multiple steps, but mainly during nucleocytoplasmic export, contributed to these varied levels of protein expression. An intron of the β-globin gene was also able to promote expression in a manner identical to that of the nefm intron, implying a more general preference for certain introns in controlling nefm expression. These results expand our knowledge of intron-mediated gene expression to encompass neurofilaments, indicating an additional layer of complexity in the control of a cytoskeletal gene needed for developing and maintaining healthy axons.
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Affiliation(s)
- Chen Wang
- Department of Biological Sciences and the Center for Neuroscience Research, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Ben G Szaro
- Department of Biological Sciences and the Center for Neuroscience Research, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY 12222, USA
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40
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Tarn WY, Kuo HC, Yu HI, Liu SW, Tseng CT, Dhananjaya D, Hung KY, Tu CC, Chang SH, Huang GJ, Chiu IM. RBM4 promotes neuronal differentiation and neurite outgrowth by modulating Numb isoform expression. Mol Biol Cell 2016; 27:1676-83. [PMID: 27009199 PMCID: PMC4865323 DOI: 10.1091/mbc.e15-11-0798] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 03/18/2016] [Indexed: 01/22/2023] Open
Abstract
RBM4 modulates alternative exon selection of Numb and up-regulates proneural Mash1 gene expression, possibly via specific Numb isoforms. RBM4 overexpression promotes neuronal cell differentiation. Moreover, RBM4 is essential for neurite outgrowth in primary cortical neurons by modulating specific Numb isoform expression. RBM4 participates in cell differentiation by regulating tissue-specific alternative pre-mRNA splicing. RBM4 also has been implicated in neurogenesis in the mouse embryonic brain. Using mouse embryonal carcinoma P19 cells as a neural differentiation model, we observed a temporal correlation between RBM4 expression and a change in splicing isoforms of Numb, a cell-fate determination gene. Knockdown of RBM4 affected the inclusion/exclusion of exons 3 and 9 of Numb in P19 cells. RBM4-deficient embryonic mouse brain also exhibited aberrant splicing of Numb pre-mRNA. Using a splicing reporter minigene assay, we demonstrated that RBM4 promoted exon 3 inclusion and exon 9 exclusion. Moreover, we found that RBM4 depletion reduced the expression of the proneural gene Mash1, and such reduction was reversed by an RBM4-induced Numb isoform containing exon 3 but lacking exon 9. Accordingly, induction of ectopic RBM4 expression in neuronal progenitor cells increased Mash1 expression and promoted cell differentiation. Finally, we found that RBM4 was also essential for neurite outgrowth from cortical neurons in vitro. Neurite outgrowth defects of RBM4-depleted neurons were rescued by RBM4-induced exon 9–lacking Numb isoforms. Therefore our findings indicate that RBM4 modulates exon selection of Numb to generate isoforms that promote neuronal cell differentiation and neurite outgrowth.
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Affiliation(s)
- Woan-Yuh Tarn
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Hung-Che Kuo
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Hsin-I Yu
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Shin-Wu Liu
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Ching-Tzu Tseng
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Dodda Dhananjaya
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Kuan-Yang Hung
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Chi-Chiang Tu
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Shuo-Hsiu Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Guo-Jen Huang
- Graduate Institute of Biomedical Sciences, Chung-Gung University, Tao-Yuan City 33302, Taiwan
| | - Ing-Ming Chiu
- National Health Research Institutes, Chu-Nan 35053, Taiwan
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Linares AJ, Lin CH, Damianov A, Adams KL, Novitch BG, Black DL. The splicing regulator PTBP1 controls the activity of the transcription factor Pbx1 during neuronal differentiation. eLife 2015; 4:e09268. [PMID: 26705333 PMCID: PMC4755740 DOI: 10.7554/elife.09268] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 12/22/2015] [Indexed: 12/13/2022] Open
Abstract
The RNA-binding proteins PTBP1 and PTBP2 control programs of alternative splicing during neuronal development. PTBP2 was found to maintain embryonic splicing patterns of many synaptic and cytoskeletal proteins during differentiation of neuronal progenitor cells (NPCs) into early neurons. However, the role of the earlier PTBP1 program in embryonic stem cells (ESCs) and NPCs was not clear. We show that PTBP1 controls a program of neuronal gene expression that includes the transcription factor Pbx1. We identify exons specifically regulated by PTBP1 and not PTBP2 as mouse ESCs differentiate into NPCs. We find that PTBP1 represses Pbx1 exon 7 and the expression of the neuronal Pbx1a isoform in ESCs. Using CRISPR-Cas9 to delete regulatory elements for exon 7, we induce Pbx1a expression in ESCs, finding that this activates transcription of neuronal genes. Thus, PTBP1 controls the activity of Pbx1 to suppress its neuronal transcriptional program prior to induction of NPC development. DOI:http://dx.doi.org/10.7554/eLife.09268.001 The neurons that transmit information around the nervous system develop in several stages. Embryonic stem cells specialize to form neuronal progenitor cells, which then develop into neurons. These cell types have different characteristics, in part because they make different proteins or different versions of the same proteins. To make a protein, the DNA sequence of a gene is used to build a molecule of ribonucleic acid (RNA) that acts as a template for the protein. However, not all of this sequence codes for the protein. The non-coding regions must be removed from the RNA, and the remaining “exons” joined together to form the final “mRNA” template. Not all of the exons are necessarily included in the final mRNA molecule. By joining together different combinations of exons, several different versions of a protein can be produced from a single gene. This process is known as alternative splicing. One way that alternative splicing is controlled is through proteins that bind to RNA and determine which exons are included or excluded from the final mRNA molecule. PTBP1 is an RNA-binding protein that controls alternative splicing in embryonic stem cells and neuronal progenitor cells. Embryonic stem cells have the ability to develop into all the cells of the body. In contrast, neuronal progenitor cells are restricted in their development and only give rise to specialized cells of the nervous system. The role of PTBP1 in these properties was not clear. Linares et al. have now used a range of techniques to study the RNA molecules produced in these two cell types and how these RNAs change when PTBP1 is removed. This identified many RNAs whose splicing is regulated by PTBP1, including mRNAs of the gene that produces a protein called Pbx1, which is an important regulator of neuronal development. Further investigation revealed that PTBP1 prevents a particular exon being included in the mRNA template for Pbx1. This creates an embryonic stem cell form of Pbx1 that does not affect neuronal genes. Removal of PTBP1 allows splicing of the Pbx1 exon and produces a version of Pbx1 that is found in neuronal progenitor cells and which turns on neuronal genes. Thus, through its action on Pbx1, one role of PTBP1 is to enable stem cells to maintain their non-neuronal properties and prevent their premature development into neuronal progenitor cells. The gene for Pbx1 is only one of many genes controlled by PTBP1 at the level of splicing. One challenge for the future will be to understand how these genes work together in a common program that determines the properties of stem cells. Another question regards how the different Pbx1 proteins in stem cells and in neuronal progenitors can exert different effects in the cells where they are made. DOI:http://dx.doi.org/10.7554/eLife.09268.002
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Affiliation(s)
- Anthony J Linares
- Molecular Biology Institute Graduate Program, University of California, Los Angeles, Los Angeles, United States
| | - Chia-Ho Lin
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, United States
| | - Andrey Damianov
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, United States
| | - Katrina L Adams
- Molecular Biology Institute Graduate Program, University of California, Los Angeles, Los Angeles, United States.,Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Bennett G Novitch
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Douglas L Black
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, United States.,Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
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Raj B, Blencowe B. Alternative Splicing in the Mammalian Nervous System: Recent Insights into Mechanisms and Functional Roles. Neuron 2015; 87:14-27. [DOI: 10.1016/j.neuron.2015.05.004] [Citation(s) in RCA: 299] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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43
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Quesnel-Vallières M, Irimia M, Cordes SP, Blencowe BJ. Essential roles for the splicing regulator nSR100/SRRM4 during nervous system development. Genes Dev 2015; 29:746-59. [PMID: 25838543 PMCID: PMC4387716 DOI: 10.1101/gad.256115.114] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Quesnel-Vallières et al. show that loss of the vertebrate- and neural-specific Ser/Arg repeat-related protein of 100 kDa (nSR100/SRRM4) impairs development of the central and peripheral nervous systems. Accompanying these developmental defects are widespread changes in alternative splicing (AS) that primarily result in shifts to nonneural patterns for different classes of splicing events. The main component of the altered AS program comprises 3- to 27-nt neural microexons, and inclusion of a 6-nt nSR100-activated microexon in Unc13b transcripts is sufficient to rescue a neuritogenesis defect in nSR100 mutant primary neurons. Alternative splicing (AS) generates vast transcriptomic complexity in the vertebrate nervous system. However, the extent to which trans-acting splicing regulators and their target AS regulatory networks contribute to nervous system development is not well understood. To address these questions, we generated mice lacking the vertebrate- and neural-specific Ser/Arg repeat-related protein of 100 kDa (nSR100/SRRM4). Loss of nSR100 impairs development of the central and peripheral nervous systems in part by disrupting neurite outgrowth, cortical layering in the forebrain, and axon guidance in the corpus callosum. Accompanying these developmental defects are widespread changes in AS that primarily result in shifts to nonneural patterns for different classes of splicing events. The main component of the altered AS program comprises 3- to 27-nucleotide (nt) neural microexons, an emerging class of highly conserved AS events associated with the regulation of protein interaction networks in developing neurons and neurological disorders. Remarkably, inclusion of a 6-nt, nSR100-activated microexon in Unc13b transcripts is sufficient to rescue a neuritogenesis defect in nSR100 mutant primary neurons. These results thus reveal critical in vivo neurodevelopmental functions of nSR100 and further link these functions to a conserved program of neuronal microexon splicing.
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Affiliation(s)
- Mathieu Quesnel-Vallières
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Manuel Irimia
- Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Sabine P Cordes
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Benjamin J Blencowe
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada;
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Alternative splicing coupled nonsense-mediated decay generates neuronal cell type-specific expression of SLM proteins. J Neurosci 2015; 34:16755-61. [PMID: 25505328 DOI: 10.1523/jneurosci.3395-14.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The unique physiological and morphological properties of neuronal populations are crucial for the appropriate functioning of neuronal circuits. Alternative splicing represents an attractive mechanism for generating cell type-specific molecular repertoires that steer neuronal development and function. However, the mechanisms that link neuronal identity to alternative splicing programs are poorly understood. We report that cell type-specific, mutually exclusive expression of two alternative splicing regulators, SLM1 and SLM2, in the mouse hippocampus is achieved by a cross-repression mechanism. Deletion of SLM2 in vivo modifies alternative splicing of its paralog Slm1 and stabilizes its mRNA, resulting in expression of SLM1 in previously SLM2-expressing cells. Despite this ectopic upregulation of SLM1, loss of SLM2 severely disrupts the alternative splicing regulation of Nrxn1, Nrxn2, and Nrxn3, highlighting that the two SLM paralogs have partially divergent functions. Our study uncovers a hierarchical, SLM2-dependent mechanism for establishing cell type-specific expression of neuronal splicing regulators in vivo.
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Quintens R, Verreet T, Janssen A, Neefs M, Leysen L, Michaux A, Verslegers M, Samari N, Pani G, Verheyde J, Baatout S, Benotmane MA. Identification of novel radiation-induced p53-dependent transcripts extensively regulated during mouse brain development. Biol Open 2015; 4:331-44. [PMID: 25681390 PMCID: PMC4359739 DOI: 10.1242/bio.20149969] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Ionizing radiation is a potent activator of the tumor suppressor gene p53, which itself regulates the transcription of genes involved in canonical pathways such as the cell cycle, DNA repair and apoptosis as well as other biological processes like metabolism, autophagy, differentiation and development. In this study, we performed a meta-analysis on gene expression data from different in vivo and in vitro experiments to identify a signature of early radiation-responsive genes which were predicted to be predominantly regulated by p53. Moreover, we found that several genes expressed different transcript isoforms after irradiation in a p53-dependent manner. Among this gene signature, we identified novel p53 targets, some of which have not yet been functionally characterized. Surprisingly, in contrast to genes from the canonical p53-regulated pathways, our gene signature was found to be highly enriched during embryonic and post-natal brain development and during in vitro neuronal differentiation. Furthermore, we could show that for a number of genes, radiation-responsive transcript variants were upregulated during development and differentiation, while radiation non-responsive variants were not. This suggests that radiation exposure of the developing brain and immature cortical neurons results in the p53-mediated activation of a neuronal differentiation program. Overall, our results further increase the knowledge of the radiation-induced p53 network of the embryonic brain and provide more evidence concerning the importance of p53 and its transcriptional targets during mouse brain development.
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Affiliation(s)
- Roel Quintens
- Radiobiology Unit, Belgian Nuclear Research Centre, SCK•CEN, B-2400 Mol, Belgium
| | - Tine Verreet
- Radiobiology Unit, Belgian Nuclear Research Centre, SCK•CEN, B-2400 Mol, Belgium Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, B-3000 Leuven, Belgium
| | - Ann Janssen
- Radiobiology Unit, Belgian Nuclear Research Centre, SCK•CEN, B-2400 Mol, Belgium
| | - Mieke Neefs
- Radiobiology Unit, Belgian Nuclear Research Centre, SCK•CEN, B-2400 Mol, Belgium
| | - Liselotte Leysen
- Radiobiology Unit, Belgian Nuclear Research Centre, SCK•CEN, B-2400 Mol, Belgium
| | - Arlette Michaux
- Radiobiology Unit, Belgian Nuclear Research Centre, SCK•CEN, B-2400 Mol, Belgium
| | - Mieke Verslegers
- Radiobiology Unit, Belgian Nuclear Research Centre, SCK•CEN, B-2400 Mol, Belgium
| | - Nada Samari
- Radiobiology Unit, Belgian Nuclear Research Centre, SCK•CEN, B-2400 Mol, Belgium
| | - Giuseppe Pani
- Radiobiology Unit, Belgian Nuclear Research Centre, SCK•CEN, B-2400 Mol, Belgium Present address: Nutritional Biochemistry and Space Biology Lab, Department of Pharmacology and Bio-molecular Sciences, Università degli Studi di Milano, 20122 Milano, Italy
| | - Joris Verheyde
- Radiobiology Unit, Belgian Nuclear Research Centre, SCK•CEN, B-2400 Mol, Belgium
| | - Sarah Baatout
- Radiobiology Unit, Belgian Nuclear Research Centre, SCK•CEN, B-2400 Mol, Belgium Cell Systems and Imaging Research Group (CSI), Department of Molecular Biotechnology, Ghent University, B-9000 Ghent, Belgium
| | - Mohammed A Benotmane
- Radiobiology Unit, Belgian Nuclear Research Centre, SCK•CEN, B-2400 Mol, Belgium
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Antonacci S, Forand D, Wolf M, Tyus C, Barney J, Kellogg L, Simon MA, Kerr G, Wells KL, Younes S, Mortimer NT, Olesnicky EC, Killian DJ. Conserved RNA-binding proteins required for dendrite morphogenesis in Caenorhabditis elegans sensory neurons. G3 (BETHESDA, MD.) 2015; 5:639-53. [PMID: 25673135 PMCID: PMC4390579 DOI: 10.1534/g3.115.017327] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/09/2015] [Indexed: 01/22/2023]
Abstract
The regulation of dendritic branching is critical for sensory reception, cell-cell communication within the nervous system, learning, memory, and behavior. Defects in dendrite morphology are associated with several neurologic disorders; thus, an understanding of the molecular mechanisms that govern dendrite morphogenesis is important. Recent investigations of dendrite morphogenesis have highlighted the importance of gene regulation at the posttranscriptional level. Because RNA-binding proteins mediate many posttranscriptional mechanisms, we decided to investigate the extent to which conserved RNA-binding proteins contribute to dendrite morphogenesis across phyla. Here we identify a core set of RNA-binding proteins that are important for dendrite morphogenesis in the PVD multidendritic sensory neuron in Caenorhabditis elegans. Homologs of each of these genes were previously identified as important in the Drosophila melanogaster dendritic arborization sensory neurons. Our results suggest that RNA processing, mRNA localization, mRNA stability, and translational control are all important mechanisms that contribute to dendrite morphogenesis, and we present a conserved set of RNA-binding proteins that regulate these processes in diverse animal species. Furthermore, homologs of these genes are expressed in the human brain, suggesting that these RNA-binding proteins are candidate regulators of dendrite development in humans.
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Affiliation(s)
- Simona Antonacci
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Daniel Forand
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado 80918
| | - Margaret Wolf
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Courtney Tyus
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Julia Barney
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Leah Kellogg
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Margo A Simon
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Genevieve Kerr
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Kristen L Wells
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Serena Younes
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado 80918
| | - Nathan T Mortimer
- Department of Biological Sciences, University of Denver, Denver, Colorado 80208
| | - Eugenia C Olesnicky
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado 80918
| | - Darrell J Killian
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
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47
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Genetic variability in the regulation of gene expression in ten regions of the human brain. Nat Neurosci 2014; 17:1418-1428. [PMID: 25174004 DOI: 10.1038/nn.3801] [Citation(s) in RCA: 485] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 07/30/2014] [Indexed: 12/12/2022]
Abstract
Germ-line genetic control of gene expression occurs via expression quantitative trait loci (eQTLs). We present a large, exon-specific eQTL data set covering ten human brain regions. We found that cis-eQTL signals (within 1 Mb of their target gene) were numerous, and many acted heterogeneously among regions and exons. Co-regulation analysis of shared eQTL signals produced well-defined modules of region-specific co-regulated genes, in contrast to standard coexpression analysis of the same samples. We report cis-eQTL signals for 23.1% of catalogued genome-wide association study hits for adult-onset neurological disorders. The data set is publicly available via public data repositories and via http://www.braineac.org/. Our study increases our understanding of the regulation of gene expression in the human brain and will be of value to others pursuing functional follow-up of disease-associated variants.
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48
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Emerging roles for hnRNPs in post-transcriptional regulation: what can we learn from flies? Chromosoma 2014; 123:515-27. [PMID: 24913828 DOI: 10.1007/s00412-014-0470-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 05/21/2014] [Accepted: 05/23/2014] [Indexed: 12/13/2022]
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a highly conserved family of RNA-binding proteins able to associate with nascent RNAs in order to support their localization, maturation and translation. Research over this last decade has remarked the importance of gene regulatory processes at post-transcriptional level, highlighting the emerging roles of hnRNPs in several essential biological events. Indeed, hnRNPs are key factors in regulating gene expression, thus, having a number of roles in many biological pathways. Moreover, failure of the activities catalysed by hnRNPs affects various biological processes and may underlie several human diseases including cancer, diabetes and neurodegenerative syndromes. In this review, we summarize some of hnRNPs' roles in the model organism Drosophila melanogaster, particularly focusing on their participation in all aspects of post-transcriptional regulation as well as their conserved role and involvement in the aetiology of human pathologies.
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49
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Norris AD, Gao S, Norris ML, Ray D, Ramani AK, Fraser AG, Morris Q, Hughes TR, Zhen M, Calarco JA. A pair of RNA-binding proteins controls networks of splicing events contributing to specialization of neural cell types. Mol Cell 2014; 54:946-959. [PMID: 24910101 DOI: 10.1016/j.molcel.2014.05.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/04/2014] [Accepted: 04/24/2014] [Indexed: 11/16/2022]
Abstract
Alternative splicing is important for the development and function of the nervous system, but little is known about the differences in alternative splicing between distinct types of neurons. Furthermore, the factors that control cell-type-specific splicing and the physiological roles of these alternative isoforms are unclear. By monitoring alternative splicing at single-cell resolution in Caenorhabditis elegans, we demonstrate that splicing patterns in different neurons are often distinct and highly regulated. We identify two conserved RNA-binding proteins, UNC-75/CELF and EXC-7/Hu/ELAV, which regulate overlapping networks of splicing events in GABAergic and cholinergic neurons. We use the UNC-75 exon network to discover regulators of synaptic transmission and to identify unique roles for isoforms of UNC-64/Syntaxin, a protein required for synaptic vesicle fusion. Our results indicate that combinatorial regulation of alternative splicing in distinct neurons provides a mechanism to specialize metazoan nervous systems.
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Affiliation(s)
- Adam D Norris
- FAS Center for Systems Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | - Shangbang Gao
- Lunenfeld-Tanenbaum Research Institute, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Megan L Norris
- FAS Center for Systems Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | - Debashish Ray
- Donnelly Centre for Cellular and Biomolecular Research, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Arun K Ramani
- Donnelly Centre for Cellular and Biomolecular Research, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Andrew G Fraser
- Donnelly Centre for Cellular and Biomolecular Research, 160 College Street, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Quaid Morris
- Donnelly Centre for Cellular and Biomolecular Research, 160 College Street, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Timothy R Hughes
- Donnelly Centre for Cellular and Biomolecular Research, 160 College Street, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research Institute, 600 University Avenue, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
| | - John A Calarco
- FAS Center for Systems Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA.
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50
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Abbott JA, Francklyn CS, Robey-Bond SM. Transfer RNA and human disease. Front Genet 2014; 5:158. [PMID: 24917879 PMCID: PMC4042891 DOI: 10.3389/fgene.2014.00158] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 05/14/2014] [Indexed: 12/25/2022] Open
Abstract
Pathological mutations in tRNA genes and tRNA processing enzymes are numerous and result in very complicated clinical phenotypes. Mitochondrial tRNA (mt-tRNA) genes are “hotspots” for pathological mutations and over 200 mt-tRNA mutations have been linked to various disease states. Often these mutations prevent tRNA aminoacylation. Disrupting this primary function affects protein synthesis and the expression, folding, and function of oxidative phosphorylation enzymes. Mitochondrial tRNA mutations manifest in a wide panoply of diseases related to cellular energetics, including COX deficiency (cytochrome C oxidase), mitochondrial myopathy, MERRF (Myoclonic Epilepsy with Ragged Red Fibers), and MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes). Diseases caused by mt-tRNA mutations can also affect very specific tissue types, as in the case of neurosensory non-syndromic hearing loss and pigmentary retinopathy, diabetes mellitus, and hypertrophic cardiomyopathy. Importantly, mitochondrial heteroplasmy plays a role in disease severity and age of onset as well. Not surprisingly, mutations in enzymes that modify cytoplasmic and mitochondrial tRNAs are also linked to a diverse range of clinical phenotypes. In addition to compromised aminoacylation of the tRNAs, mutated modifying enzymes can also impact tRNA expression and abundance, tRNA modifications, tRNA folding, and even tRNA maturation (e.g., splicing). Some of these pathological mutations in tRNAs and processing enzymes are likely to affect non-canonical tRNA functions, and contribute to the diseases without significantly impacting on translation. This chapter will review recent literature on the relation of mitochondrial and cytoplasmic tRNA, and enzymes that process tRNAs, to human disease. We explore the mechanisms involved in the clinical presentation of these various diseases with an emphasis on neurological disease.
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Affiliation(s)
- Jamie A Abbott
- Department of Biochemistry, College of Medicine, University of Vermont Burlington, VT, USA
| | | | - Susan M Robey-Bond
- Department of Biochemistry, College of Medicine, University of Vermont Burlington, VT, USA
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