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Zhong Y, Yang Y, Wang X, Ren B, Wang X, Shan G, Chen L. Systematic identification and characterization of exon-intron circRNAs. Genome Res 2024; 34:376-393. [PMID: 38609186 PMCID: PMC11067877 DOI: 10.1101/gr.278590.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 03/07/2024] [Indexed: 04/14/2024]
Abstract
Exon-intron circRNAs (EIciRNAs) are a circRNA subclass with retained introns. Global features of EIciRNAs remain largely unexplored, mainly owing to the lack of bioinformatic tools. The regulation of intron retention (IR) in EIciRNAs and the associated functionality also require further investigation. We developed a framework, FEICP, which efficiently detected EIciRNAs from high-throughput sequencing (HTS) data. EIciRNAs are distinct from exonic circRNAs (EcircRNAs) in aspects such as with larger length, localization in the nucleus, high tissue specificity, and enrichment mostly in the brain. Deep learning analyses revealed that compared with regular introns, the retained introns of circRNAs (CIRs) are shorter in length, have weaker splice site strength, and have higher GC content. Compared with retained introns in linear RNAs (LIRs), CIRs are more likely to form secondary structures and show greater sequence conservation. CIRs are closer to the 5'-end, whereas LIRs are closer to the 3'-end of transcripts. EIciRNA-generating genes are more actively transcribed and associated with epigenetic marks of gene activation. Computational analyses and genome-wide CRISPR screening revealed that SRSF1 binds to CIRs and inhibits the biogenesis of most EIciRNAs. SRSF1 regulates the biogenesis of EIciLIMK1, which enhances the expression of LIMK1 in cis to boost neuronal differentiation, exemplifying EIciRNA physiological function. Overall, our study has developed the FEICP pipeline to identify EIciRNAs from HTS data, and reveals multiple features of CIRs and EIciRNAs. SRSF1 has been identified to regulate EIciRNA biogenesis. EIciRNAs and the regulation of EIciRNA biogenesis play critical roles in neuronal differentiation.
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Affiliation(s)
- Yinchun Zhong
- Department of Cardiology, The First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Yan Yang
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Clinical Laboratory, The First Affiliated Hospital of USTC, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Xiaolin Wang
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Clinical Laboratory, The First Affiliated Hospital of USTC, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Bingbing Ren
- Department of Pulmonary and Critical Care Medicine, Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
| | - Xueren Wang
- Department of Anesthesiology, Shanxi Bethune Hospital, Taiyuan 030032, China;
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ge Shan
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Clinical Laboratory, The First Affiliated Hospital of USTC, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230027, China;
| | - Liang Chen
- Department of Cardiology, The First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230027, China
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2
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Reyes AV, Shrestha R, Grismer TS, Byun D, Xu SL. Impact of alternative splicing on Arabidopsis proteome. bioRxiv 2024:2024.02.29.582853. [PMID: 38496481 PMCID: PMC10942332 DOI: 10.1101/2024.02.29.582853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Alternative splicing is an important regulatory process in eukaryotes. In plants, the major form of alternative splicing is intron retention. Despite its importance, the global impact of AS on the Arabidopsis proteome has not been investigated. In this study, we address this gap by performing a comprehensive integrated analysis of how changes in AS can affect the Arabidopsis proteome using mutants that disrupt ACINUS and PININ, two evolutionarily conserved alternative splicing factors. We used tandem mass tagging (TMT) with real-time search MS3 (RTS-SPS-MS3) coupled with extensive sample fractionations to achieve very high coverage and accurate protein quantification. We then integrated our proteomic data with transcriptomic data to assess how transcript changes and increased intron retention (IIR) affect the proteome. For differentially expressed transcripts, we have observed a weak to moderate correlation between transcript changes and protein changes. Our studies revealed that some IIRs have no effect on either transcript or protein levels, while some IIRs can significantly affect protein levels. Surprisingly, we found that IIRs have a much smaller effect on increasing protein diversity. Notably, the increased intron retention events detected in the double mutant are also detected in the WT under various biotic or abiotic stresses. We further investigated the characteristics of the retained introns. Our extensive proteomic data help to guide the phenotypic analysis and reveal that collective protein changes contribute to the observed phenotypes of the increased anthocyanin, pale green, reduced growth, and short root observed in the acinus pnn double mutant. Overall, our study provides insight into the intricate regulatory mechanism of intron retention and its impact on protein abundance in plants.
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Affiliation(s)
- Andres V Reyes
- Division of biosphere science and engineering, Carnegie Institution for Science, Stanford, California, USA
- Carnegie Mass Spectrometry Facility, Carnegie Institution for Science, Stanford, California, USA
| | - Ruben Shrestha
- Division of biosphere science and engineering, Carnegie Institution for Science, Stanford, California, USA
| | - TaraBryn S Grismer
- Division of biosphere science and engineering, Carnegie Institution for Science, Stanford, California, USA
- Carnegie Mass Spectrometry Facility, Carnegie Institution for Science, Stanford, California, USA
| | - Danbi Byun
- Division of biosphere science and engineering, Carnegie Institution for Science, Stanford, California, USA
| | - Shou-Ling Xu
- Division of biosphere science and engineering, Carnegie Institution for Science, Stanford, California, USA
- Carnegie Mass Spectrometry Facility, Carnegie Institution for Science, Stanford, California, USA
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3
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Gómez-Montalvo J, de Obeso Fernández Del Valle A, De la Cruz Gutiérrez LF, Gonzalez-Meljem JM, Scheckhuber CQ. Replicative aging in yeast involves dynamic intron retention patterns associated with mRNA processing/export and protein ubiquitination. Microb Cell 2024; 11:69-78. [PMID: 38414808 PMCID: PMC10897858 DOI: 10.15698/mic2024.02.816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/25/2024] [Accepted: 02/01/2024] [Indexed: 02/29/2024]
Abstract
Saccharomyces cerevisiae (baker's yeast) has yielded relevant insights into some of the basic mechanisms of organismal aging. Among these are genomic instability, oxidative stress, caloric restriction and mitochondrial dysfunction. Several genes are known to have an impact on the aging process, with corresponding mutants exhibiting short- or long-lived phenotypes. Research dedicated to unraveling the underlying cellular mechanisms can support the identification of conserved mechanisms of aging in other species. One of the hitherto less studied fields in yeast aging is how the organism regulates its gene expression at the transcriptional level. To our knowledge, we present the first investigation into alternative splicing, particularly intron retention, during replicative aging of S. cerevisiae. This was achieved by utilizing the IRFinder algorithm on a previously published RNA-seq data set by Janssens et al. (2015). In the present work, 44 differentially retained introns in 43 genes were identified during replicative aging. We found that genes with altered intron retention do not display significant changes in overall transcript levels. It was possible to functionally assign distinct groups of these genes to the cellular processes of mRNA processing and export (e.g., YRA1) in early and middle-aged yeast, and protein ubiquitination (e.g., UBC5) in older cells. In summary, our work uncovers a previously unexplored layer of the transcriptional program of yeast aging and, more generally, expands the knowledge on the occurrence of alternative splicing in baker's yeast.
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Affiliation(s)
- Jesús Gómez-Montalvo
- Tecnologico de Monterrey, Escuela de Ingeniería y Ciencias, Ave. Eugenio Garza Sada 2501, Monterrey, N.L., México
| | | | | | - Jose Mario Gonzalez-Meljem
- Tecnologico de Monterrey, Escuela de Ingeniería y Ciencias, Ave. Eugenio Garza Sada 2501, Monterrey, N.L., México
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Roth JF, Braunschweig U, Wu M, Li JD, Lin ZY, Larsen B, Weatheritt RJ, Gingras AC, Blencowe BJ. Systematic analysis of alternative exon-dependent interactome remodeling reveals multitasking functions of gene regulatory factors. Mol Cell 2023; 83:4222-4238.e10. [PMID: 38065061 DOI: 10.1016/j.molcel.2023.10.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 08/09/2023] [Accepted: 10/24/2023] [Indexed: 12/18/2023]
Abstract
Alternative splicing significantly expands biological complexity, particularly in the vertebrate nervous system. Increasing evidence indicates that developmental and tissue-dependent alternative exons often control protein-protein interactions; yet, only a minor fraction of these events have been characterized. Using affinity purification-mass spectrometry (AP-MS), we show that approximately 60% of analyzed neural-differential exons in proteins previously implicated in transcriptional regulation result in the gain or loss of interaction partners, which in some cases form unexpected links with coupled processes. Notably, a neural exon in Chtop regulates its interaction with the Prmt1 methyltransferase and DExD-Box helicases Ddx39b/a, affecting its methylation and activity in promoting RNA export. Additionally, a neural exon in Sap30bp affects interactions with RNA processing factors, modulating a critical function of Sap30bp in promoting the splicing of <100 nt "mini-introns" that control nuclear RNA levels. AP-MS is thus a powerful approach for elucidating the multifaceted functions of proteins imparted by context-dependent alternative exons.
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Affiliation(s)
- Jonathan F Roth
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | | | - Mingkun Wu
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Jack Daiyang Li
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Zhen-Yuan Lin
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health, Toronto, ON M5G 1X5, Canada
| | - Brett Larsen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health, Toronto, ON M5G 1X5, Canada
| | - Robert J Weatheritt
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; EMBL Australia, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Benjamin J Blencowe
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
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Li Z, Qin C, Zhao B, Wang Y, Li T, Zhao Y, Wang W. DHX38 restricts chemoresistance by regulating the alternative pre-mRNA splicing of RELL2 in pancreatic ductal adenocarcinoma. PLoS Genet 2023; 19:e1010847. [PMID: 37506056 PMCID: PMC10381071 DOI: 10.1371/journal.pgen.1010847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 06/27/2023] [Indexed: 07/30/2023] Open
Abstract
Intron retention plays an important role in cancer progression and chemotherapy resistance and seems to be essential for the maintenance of genome stability in cancer. Here, our goal was to analyze the role of receptor expressed in lymphoid tissue (Relt)-like 2 (RELL2) intron 4 retention in promoting pancreatic ductal adenocarcinoma (PDAC) progression. Our results showed that intron retention (IR) occurs at the fourth intron of RELL2 transcript in gemcitabine resistant PDAC cells, however, the regulatory mechanism and the clinical implications of IR of RELL2 are unclear. Firstly, we found that RELL2 plays an anti-oncogenic role in PDAC by performing in vitro functional assays including cell proliferation, GEM cytotoxicity assay and apoptosis. Subsequently, we identified the upstream gene of RELL2, DEAH-Box Helicase 38 (DHX38), and demonstrated the direct interaction between DHX38 and RELL2 by RIP-qPCR. We also found that altered expression of DHX38 resulted in corresponding changes in intron 4 retention of RELL2. Importantly, we unveiled that overexpression of DHX38 on the basis of knocking down of the fourth intron of RELL2 resulted in an impaired intron 4 intention. Overall, our study identified a new IR site in PDAC, which could be a possible target for PDAC therapy.
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Affiliation(s)
- Zeru Li
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Cheng Qin
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Bangbo Zhao
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Yuanyang Wang
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Tianyu Li
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Yutong Zhao
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Weibin Wang
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P.R. China
- Key Laboratory of Research in Pancreatic Tumor, Chinese Academy of Medical Sciences, Beijing, P.R. China
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Rezvykh A, Ustyugov A, Chaprov K, Teterina E, Nebogatikov V, Spasskaya D, Evgen’ev M, Morozov A, Funikov S. Cytoplasmic aggregation of mutant FUS causes multistep RNA splicing perturbations in the course of motor neuron pathology. Nucleic Acids Res 2023; 51:5810-5830. [PMID: 37115004 PMCID: PMC10287951 DOI: 10.1093/nar/gkad319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 04/12/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
Dysfunction of the RNA-binding protein (RBP) FUS implicated in RNA metabolism can cause amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases. Mutations affecting FUS nuclear localization can drive RNA splicing defects and stimulate the formation of non-amyloid inclusions in affected neurons. However, the mechanism by which FUS mutations contribute to the development of ALS remains uncertain. Here we describe a pattern of RNA splicing changes in the dynamics of the continuous proteinopathy induced by mislocalized FUS. We show that the decrease in intron retention of FUS-associated transcripts represents the hallmark of the pathogenesis of ALS and is the earliest molecular event in the course of progression of the disease. As FUS aggregation increases, the pattern of RNA splicing changes, becoming more complex, including a decrease in the inclusion of neuron-specific microexons and induction of cryptic exon splicing due to the sequestration of additional RBPs into FUS aggregates. Crucially, the identified features of the pathological splicing pattern are also observed in ALS patients in both sporadic and familial cases. Our data provide evidence that both a loss of nuclear FUS function due to mislocalization and the subsequent cytoplasmic aggregation of mutant protein lead to the disruption of RNA splicing in a multistep fashion during FUS aggregation.
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Affiliation(s)
- Alexander P Rezvykh
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, 119991, Russian Federation
| | - Aleksey A Ustyugov
- Institute of Physiologically Active Compounds at Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of Russian Academy of Sciences, Chernogolovka, 142432, Russian Federation
| | - Kirill D Chaprov
- Institute of Physiologically Active Compounds at Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of Russian Academy of Sciences, Chernogolovka, 142432, Russian Federation
| | - Ekaterina V Teterina
- Institute of Physiologically Active Compounds at Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of Russian Academy of Sciences, Chernogolovka, 142432, Russian Federation
| | - Vladimir O Nebogatikov
- Institute of Physiologically Active Compounds at Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of Russian Academy of Sciences, Chernogolovka, 142432, Russian Federation
| | - Daria S Spasskaya
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, 119991, Russian Federation
| | - Michael B Evgen’ev
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, 119991, Russian Federation
| | - Alexey V Morozov
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, 119991, Russian Federation
| | - Sergei Yu Funikov
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, 119991, Russian Federation
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7
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Feng Y, Chen Z, Xu Y, Han Y, Jia X, Wang Z, Zhang N, Lv W. The central inflammatory regulator IκBζ: induction, regulation and physiological functions. Front Immunol 2023; 14:1188253. [PMID: 37377955 PMCID: PMC10291074 DOI: 10.3389/fimmu.2023.1188253] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
IκBζ (encoded by NFKBIZ) is the most recently identified IkappaB family protein. As an atypical member of the IkappaB protein family, NFKBIZ has been the focus of recent studies because of its role in inflammation. Specifically, it is a key gene in the regulation of a variety of inflammatory factors in the NF-KB pathway, thereby affecting the progression of related diseases. In recent years, investigations into NFKBIZ have led to greater understanding of this gene. In this review, we summarize the induction of NFKBIZ and then elucidate its transcription, translation, molecular mechanism and physiological function. Finally, the roles played by NFKBIZ in psoriasis, cancer, kidney injury, autoimmune diseases and other diseases are described. NFKBIZ functions are universal and bidirectional, and therefore, this gene may exert a great influence on the regulation of inflammation and inflammation-related diseases.
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Affiliation(s)
- Yanpeng Feng
- Department of Neurosurgery & Pathophysiology, Institute of Neuroregeneration & Neurorehabilitation, Qingdao University, Qingdao, China
| | - Zhiyuan Chen
- Department of Neurosurgery & Pathophysiology, Institute of Neuroregeneration & Neurorehabilitation, Qingdao University, Qingdao, China
| | - Yi Xu
- Department of Neurosurgery & Pathophysiology, Institute of Neuroregeneration & Neurorehabilitation, Qingdao University, Qingdao, China
| | - Yuxuan Han
- Department of Neurosurgery & Pathophysiology, Institute of Neuroregeneration & Neurorehabilitation, Qingdao University, Qingdao, China
| | - Xiujuan Jia
- Department of Geriatrics, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Zixuan Wang
- Department of Geriatrics, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Nannan Zhang
- Department of Geriatrics, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Wenjing Lv
- Department of Neurosurgery & Pathophysiology, Institute of Neuroregeneration & Neurorehabilitation, Qingdao University, Qingdao, China
- Department of Geriatrics, The Affiliated Hospital of Qingdao University, Qingdao, China
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Petrillo E. Do not panic: An intron-centric guide to alternative splicing. Plant Cell 2023; 35:1752-1761. [PMID: 36648241 PMCID: PMC10226583 DOI: 10.1093/plcell/koad009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/05/2022] [Accepted: 01/11/2023] [Indexed: 05/30/2023]
Abstract
This review is an attempt to establish concepts of splicing and alternative splicing giving proper relevance to introns, the key actors in this mechanism. It might also work as a guide for those who found their favorite gene undergoes alternative splicing and could benefit from gaining a theoretical framework to understand the possible impacts of this process. This is not a thorough review of all the work in the field, but rather a critical review of some of the most relevant work done to understand the underlying mechanisms of splicing and the key questions that remain unanswered such as: What is the physiological relevance of alternative splicing? What are the functions of the different outcomes? To what extent do different alternative splicing types contribute to the proteome? Intron retention is the most frequent alternative splicing event in plants and, although scientifically neglected, it is also common in animals. This is a heterogeneous type of alternative splicing that includes different sub-types with features that have distinctive consequences in the resulting transcripts. Remarkably, intron retention can be a dead end for a transcript, but it could also be a stable intermediate whose processing is resumed upon a particular signal or change in the cell status. New sequencing technologies combined with the study of intron lariats in different conditions might help to answer key questions and could help us to understand the actual relevance of introns in gene expression regulation.
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Affiliation(s)
- Ezequiel Petrillo
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología, Molecular, y Celular, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), C1428EHA Buenos Aires, Argentina
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Wen W, Mead AJ, Thongjuea S. MARVEL: an integrated alternative splicing analysis platform for single-cell RNA sequencing data. Nucleic Acids Res 2023; 51:e29. [PMID: 36631981 PMCID: PMC10018366 DOI: 10.1093/nar/gkac1260] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 12/13/2022] [Accepted: 01/11/2023] [Indexed: 01/13/2023] Open
Abstract
Alternative splicing is an important source of heterogeneity underlying gene expression between individual cells but remains an understudied area due to the paucity of computational tools to analyze splicing dynamics at single-cell resolution. Here, we present MARVEL, a comprehensive R package for single-cell splicing analysis applicable to RNA sequencing generated from the plate- and droplet-based methods. We performed extensive benchmarking of MARVEL against available tools and demonstrated its utility by analyzing multiple publicly available datasets in diverse cell types, including in disease. MARVEL enables systematic and integrated splicing and gene expression analysis of single cells to characterize the splicing landscape and reveal biological insights.
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Affiliation(s)
- Wei Xiong Wen
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
- MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Adam J Mead
- Correspondence may also be addressed to Adam J. Mead.
| | - Supat Thongjuea
- To whom correspondence should be addressed. Tel: +49 015201091154;
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Estupiñán RA, Torres de Farias S, Gonçalves EC, Camargo M, Cruz Schneider MP. Performance of intron 7 of the β-fibrinogen gene for phylogenetic analysis: An example using gladiator frogs, Boana Gray, 1825 (Anura, Hylidae, Cophomantinae). Zookeys 2023; 1149:145-169. [DOI: 10.3897/zookeys.1149.85627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/22/2022] [Indexed: 02/24/2023] Open
Abstract
Boana, the third largest genus of Hylinae, has cryptic morphological species. The potential applicability of b-fibrinogen intron 7 – FGBI7 is explored to propose a robust phylogeny of Boana. The phylogenetic potential of FGBI7 was evaluated using maximum parsimony, MrBayes, and maximum likelihood analysis. Comparison of polymorphic sites and topologies obtained with concatenated analysis of FGBI7 and other nuclear genes (CXCR4, CXCR4, RHO, SIAH1, TYR, and 28S) allowed evaluation of the phylogenetic signal of FGBI7. Mean evolutionary rates were calculated using the sequences of the mitochondrial genes ND1 and CYTB available for Boana in GenBank. Dating of Boana and some of its groups was performed using the RelTime method with secondary calibration. FGBI7 analysis revealed high values at informative sites for parsimony. The absolute values of the mean evolutionary rate were higher for mitochondrial genes than for FGBI7. Dating of congruent Boana groups for ND1, CYTB, and FGBI7 revealed closer values between mitochondrial genes and slightly different values from those of FGBI7. Divergence times of basal groups tended to be overestimated when mtDNA was used and were more accurate when nDNA was used. Although there is evidence of phylogenetic potential arising from concatenation of specific genes, FGBI7 provides well-resolved independent gene trees. These results lead to a paradigm for linking data in phylogenomics that focuses on the uniqueness of species histories and ignores the multiplicities of individual gene histories.
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Shi X, Won M, Tang C, Ding Q, Sharma A, Wang F, Kim JS. RNA splicing based on reporter genes system: Detection, imaging and applications. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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12
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Qin J, Huang T, Wang Z, Zhang X, Wang J, Dang Q, Cui D, Wang X, Zhai Y, Zhao L, Lu G, Shao C, Li S, Liu H, Liu Z. Bud31-mediated alternative splicing is required for spermatogonial stem cell self-renewal and differentiation. Cell Death Differ 2023; 30:184-194. [PMID: 36114296 PMCID: PMC9883385 DOI: 10.1038/s41418-022-01057-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 08/17/2022] [Accepted: 08/26/2022] [Indexed: 02/01/2023] Open
Abstract
Alternative splicing (AS) is tightly regulated during cell differentiation and development. AS events are prevalent in the testis, but the splicing regulation in spermatogenesis remains unclear. Here we report that the spliceosome component Bud31 plays a crucial role during spermatogenesis in mice. Germ cell-specific knockout of Bud31 led to loss of spermatogonia and to male infertility. We further demonstrate that Bud31 is required for both spermatogonial stem cell pool maintenance and the initiation of spermatogenesis. SMART-seq revealed that deletion of Bud31 in germ cells causes widespread exon-skipping and intron retention. Particularly, we identified Cdk2 as one of the direct splicing targets of Bud31, knockout of Bud31 resulted in retention of the first intron of Cdk2, which led to a decrease in Cdk2 expression. Our findings suggest that Bud31-mediated AS within spermatogonial stem cells regulates the self-renewal and differentiation of male germ cells in mammals.
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Affiliation(s)
- Junchao Qin
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Tao Huang
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Zixiang Wang
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Xiyu Zhang
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Jing Wang
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Qianli Dang
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Donghai Cui
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Xinyu Wang
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yunjiao Zhai
- Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Ling Zhao
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Gang Lu
- CUHK-SDU Joint Laboratory on Reproductive Genetics, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Changshun Shao
- Institutes for Translational Medicine, State Key Laboratory of Radiation Medicine and Protection, Soochow University, Suzhou, China
| | - Shiyang Li
- Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Hongbin Liu
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, China.
| | - Zhaojian Liu
- Key Laboratory of Experimental Teratology, Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China.
- Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, China.
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13
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Zhang J, Lin X, Chen Y, Li T, Lee AC, Chow EY, Cho WC, Chan T. LAFITE Reveals the Complexity of Transcript Isoforms in Subcellular Fractions. Adv Sci (Weinh) 2023; 10:e2203480. [PMID: 36461702 PMCID: PMC9875686 DOI: 10.1002/advs.202203480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/28/2022] [Indexed: 06/17/2023]
Abstract
Characterization of the subcellular distribution of RNA is essential for understanding the molecular basis of biological processes. Here, the subcellular nanopore direct RNA-sequencing (DRS) of four lung cancer cell lines (A549, H1975, H358, and HCC4006) is performed, coupled with a computational pipeline, Low-abundance Aware Full-length Isoform clusTEr (LAFITE), to comprehensively analyze the full-length cytoplasmic and nuclear transcriptome. Using additional DRS and orthogonal data sets, it is shown that LAFITE outperforms current methods for detecting full-length transcripts, particularly for low-abundance isoforms that are usually overlooked due to poor read coverage. Experimental validation of six novel isoforms exclusively identified by LAFITE further confirms the reliability of this pipeline. By applying LAFITE to subcellular DRS data, the complexity of the nuclear transcriptome is revealed in terms of isoform diversity, 3'-UTR usage, m6A modification patterns, and intron retention. Overall, LAFITE provides enhanced full-length isoform identification and enables a high-resolution view of the RNA landscape at the isoform level.
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Affiliation(s)
- Jizhou Zhang
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SARChina
| | - Xiao Lin
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SARChina
| | - Yuelong Chen
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
| | - Tsz‐Ho Li
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SARChina
| | - Alan Chun‐Kit Lee
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
| | | | | | - Ting‐Fung Chan
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SARChina
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14
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Schmitz U. Overview of Computational and Experimental Methods to Identify Tissue-Specific MicroRNA Targets. Methods Mol Biol 2023; 2630:155-177. [PMID: 36689183 DOI: 10.1007/978-1-0716-2982-6_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
As ubiquitous posttranscriptional regulators of gene expression, microRNAs (miRNAs) play key roles in cell physiology and function across taxa. In the last two decades, we have gained a good understanding about miRNA biogenesis pathways, modes of action, and consequences of miRNA-mediated gene regulation. More recently, research has focused on exploring causes for miRNA dysregulation, miRNA-mediated crosstalk between genes and signaling pathways, and the role of miRNAs in disease.This chapter discusses methods for the identification of miRNA-target interactions and causes for tissue-specific miRNA-target regulation. Computational approaches for predicting miRNA target sites and assessing tissue-specific target regulation are discussed. Moreover, there is an emphasis on features that affect miRNA target recognition and how high-throughput sequencing protocols can help in assessing miRNA-mediated gene regulation on a genome-wide scale. In addition, this chapter introduces some experimental approaches for the validation of miRNA targets as well as web-based resources sharing predicted and validated miRNA-target interactions.
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Affiliation(s)
- Ulf Schmitz
- Department of Molecular & Cell Biology, College of Public Health, Medical & Vet Sciences, James Cook University, Douglas, Australia.
- Centre for Tropical Bioinformatics and Molecular Biology, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia.
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15
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David JK, Maden SK, Wood MA, Thompson RF, Nellore A. Retained introns in long RNA-seq reads are not reliably detected in sample-matched short reads. Genome Biol 2022; 23:240. [PMID: 36369064 PMCID: PMC9652823 DOI: 10.1186/s13059-022-02789-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 10/10/2022] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND There is growing interest in retained introns in a variety of disease contexts including cancer and aging. Many software tools have been developed to detect retained introns from short RNA-seq reads, but reliable detection is complicated by overlapping genes and transcripts as well as the presence of unprocessed or partially processed RNAs. RESULTS We compared introns detected by 8 tools using short RNA-seq reads with introns observed in long RNA-seq reads from the same biological specimens. We found significant disagreement among tools (Fleiss' [Formula: see text]) such that 47.7% of all detected intron retentions were not called by more than one tool. We also observed poor performance of all tools, with none achieving an F1-score greater than 0.26, and qualitatively different behaviors between general-purpose alternative splicing detection tools and tools confined to retained intron detection. CONCLUSIONS Short-read tools detect intron retention with poor recall and precision, calling into question the completeness and validity of a large percentage of putatively retained introns called by commonly used methods.
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Affiliation(s)
- Julianne K. David
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA ,Present Address: Base5 Genomics, Inc., Mountain View, CA USA
| | - Sean K. Maden
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA ,grid.21107.350000 0001 2171 9311Present Address: Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA
| | - Mary A. Wood
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.429936.30000 0004 5914 210XPortland VA Research Foundation, Portland, OR USA ,Present Address: Phase Genomics, Inc., Seattle, WA USA
| | - Reid F. Thompson
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA ,grid.484322.bDivision of Hospital and Specialty Medicine, VA Portland Healthcare System, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Radiation Medicine, Oregon Health & Science University, Portland, OR USA
| | - Abhinav Nellore
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Surgery, Oregon Health & Science University, Portland, OR USA
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16
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Petrova V, Song R, Nordström KJV, Walter J, Wong JJL, Armstrong N, Rasko JEJ, Schmitz U. Increased chromatin accessibility facilitates intron retention in specific cell differentiation states. Nucleic Acids Res 2022; 50:11563-11579. [PMID: 36354002 PMCID: PMC9723627 DOI: 10.1093/nar/gkac994] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/05/2022] [Accepted: 10/18/2022] [Indexed: 11/11/2022] Open
Abstract
Dynamic intron retention (IR) in vertebrate cells is of widespread biological importance. Aberrant IR is associated with numerous human diseases including several cancers. Despite consistent reports demonstrating that intrinsic sequence features can help introns evade splicing, conflicting findings about cell type- or condition-specific IR regulation by trans-regulatory and epigenetic mechanisms demand an unbiased and systematic analysis of IR in a controlled experimental setting. We integrated matched mRNA sequencing (mRNA-Seq), whole-genome bisulfite sequencing (WGBS), nucleosome occupancy methylome sequencing (NOMe-Seq) and chromatin immunoprecipitation sequencing (ChIP-Seq) data from primary human myeloid and lymphoid cells. Using these multi-omics data and machine learning, we trained two complementary models to determine the role of epigenetic factors in the regulation of IR in cells of the innate immune system. We show that increased chromatin accessibility, as revealed by nucleosome-free regions, contributes substantially to the retention of introns in a cell-specific manner. We also confirm that intrinsic characteristics of introns are key for them to evade splicing. This study suggests an important role for chromatin architecture in IR regulation. With an increasing appreciation that pathogenic alterations are linked to RNA processing, our findings may provide useful insights for the development of novel therapeutic approaches that target aberrant splicing.
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Affiliation(s)
- Veronika Petrova
- Computational BioMedicine Laboratory Centenary Institute, The University of Sydney, Camperdown 2050, Australia,Gene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia
| | - Renhua Song
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia,Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia
| | | | - Karl J V Nordström
- Laboratory of EpiGenetics, Saarland University, Campus A2 4, D-66123 Saarbrücken, Germany
| | - Jörn Walter
- Laboratory of EpiGenetics, Saarland University, Campus A2 4, D-66123 Saarbrücken, Germany
| | - Justin J L Wong
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia,Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia
| | - Nicola J Armstrong
- Mathematics and Statistics, Curtin University, Bentley, WA 6102, Australia
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17
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Hadar S, Meller A, Saida N, Shalgi R. Stress-induced transcriptional readthrough into neighboring genes is linked to intron retention. iScience 2022; 25:105543. [PMID: 36505935 PMCID: PMC9732411 DOI: 10.1016/j.isci.2022.105543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 07/10/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022] Open
Abstract
Exposure to certain stresses leads to readthrough transcription. Using polyA-selected RNA-seq in mouse fibroblasts subjected to heat shock, oxidative, or osmotic stress, we found that readthrough transcription can proceed into proximal downstream genes, in a phenomenon previously termed "read-in." We found that read-in genes share distinctive genomic characteristics; they are GC-rich and extremely short , with genomic features conserved in human. Using ribosome profiling, we found that read-in genes show significantly reduced translation. Strikingly, read-in genes demonstrate marked intron retention, mostly in their first introns, which could not be explained solely by their short introns and GC-richness, features often associated with intron retention. Finally, we revealed H3K36me3 enrichment upstream to read-in genes. Moreover, demarcation of exon-intron junctions by H3K36me3 was absent in read-in first introns. Our data portray a relationship between read-in and intron retention, suggesting they may have co-evolved to facilitate reduced translation of read-in genes during stress.
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Affiliation(s)
- Shani Hadar
- Department of Biochemistry, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, Haifa 31096, Israel
| | - Anatoly Meller
- Department of Biochemistry, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, Haifa 31096, Israel
| | - Naseeb Saida
- Department of Biochemistry, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, Haifa 31096, Israel
| | - Reut Shalgi
- Department of Biochemistry, Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, Haifa 31096, Israel,Corresponding author
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18
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Chen SX, Simpson E, Reiter JL, Liu Y. Bioinformatics detection of modulators controlling splicing factor-dependent intron retention in the human brain. Hum Mutat 2022; 43:1629-1641. [PMID: 35391504 PMCID: PMC9537345 DOI: 10.1002/humu.24379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 03/02/2022] [Accepted: 04/02/2022] [Indexed: 12/30/2022]
Abstract
Alternative RNA splicing is an important means of genetic control and transcriptome diversity. However, when alternative splicing events are studied independently, coordinated splicing modulated by common factors is often not recognized. As a result, the molecular mechanisms of how splicing regulators promote or repress splice site recognition in a context-dependent manner are not well understood. The functional coupling between multiple gene regulatory layers suggests that splicing is modulated by additional genetic or epigenetic components. Here, we developed a bioinformatics approach to identify causal modulators of splicing activity based on the variation of gene expression in large RNA sequencing datasets. We applied this approach in a neurological context with hundreds of dorsolateral prefrontal cortex samples. Our model is strengthened with the incorporation of genetic variants to impute gene expression in a Mendelian randomization-based approach. We identified novel modulators of the splicing factor SRSF1, including UIMC1 and the long noncoding RNA CBR3-AS1, that function over dozens of SRSF1 intron retention splicing targets. This strategy can be widely used to identify modulators of RNA-binding proteins involved in tissue-specific alternative splicing.
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Affiliation(s)
- Steven X. Chen
- Department of Medical and Molecular GeneticsIndiana University School of MedicineIndianapolisIndianaUSA
- Center for Computational Biology and BioinformaticsIndiana University School of MedicineIndianapolisIndianaUSA
| | - Ed Simpson
- Department of Medical and Molecular GeneticsIndiana University School of MedicineIndianapolisIndianaUSA
- Center for Computational Biology and BioinformaticsIndiana University School of MedicineIndianapolisIndianaUSA
| | - Jill L. Reiter
- Department of Medical and Molecular GeneticsIndiana University School of MedicineIndianapolisIndianaUSA
- Center for Computational Biology and BioinformaticsIndiana University School of MedicineIndianapolisIndianaUSA
| | - Yunlong Liu
- Department of Medical and Molecular GeneticsIndiana University School of MedicineIndianapolisIndianaUSA
- Center for Computational Biology and BioinformaticsIndiana University School of MedicineIndianapolisIndianaUSA
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19
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Petrić Howe M, Crerar H, Neeves J, Harley J, Tyzack GE, Klein P, Ramos A, Patani R, Luisier R. Physiological intron retaining transcripts in the cytoplasm abound during human motor neurogenesis. Genome Res 2022; 32:1808-1825. [PMID: 36180233 PMCID: PMC9712626 DOI: 10.1101/gr.276898.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 09/16/2022] [Indexed: 11/24/2022]
Abstract
Intron retention (IR) is now recognized as a dominant splicing event during motor neuron (MN) development; however, the role and regulation of intron-retaining transcripts (IRTs) localized to the cytoplasm remain particularly understudied. Here we show that IR is a physiological process that is spatiotemporally regulated during MN lineage restriction and that IRTs in the cytoplasm are detected in as many as 13% (n = 2297) of the genes expressed during this process. We identify a major class of cytoplasmic IRTs that are not associated with reduced expression of their own genes but instead show a high capacity for RNA-binding protein and miRNA occupancy. Finally, we show that ALS-causing VCP mutations lead to a selective increase in cytoplasmic abundance of this particular class of IRTs, which in turn temporally coincides with an increase in the nuclear expression level of predicted miRNA target genes. Altogether, our study identifies a previously unrecognized class of cytoplasmic intronic sequences with potential regulatory function beyond gene expression.
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Affiliation(s)
- Marija Petrić Howe
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, United Kingdom
| | - Hamish Crerar
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, United Kingdom
| | - Jacob Neeves
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, United Kingdom
| | - Jasmine Harley
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, United Kingdom
| | - Giulia E Tyzack
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, United Kingdom
| | - Pierre Klein
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Research Department of Structural and Molecular Biology, University College London, London WC1E 6XA, United Kingdom
| | - Andres Ramos
- Research Department of Structural and Molecular Biology, University College London, London WC1E 6XA, United Kingdom
| | - Rickie Patani
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, United Kingdom
| | - Raphaëlle Luisier
- Idiap Research Institute, Genomics and Health Informatics, CH-1920 Martigny, Switzerland
- SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
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20
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de Obeso Fernández Del Valle A, Gómez-Montalvo J, Maciver SK. Acanthamoeba castellanii exhibits intron retention during encystment. Parasitol Res 2022; 121:2615-2622. [PMID: 35776211 DOI: 10.1007/s00436-022-07578-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/14/2022] [Indexed: 11/24/2022]
Abstract
Intron retention (IR) refers to the mechanism of alternative splicing in which an intron is not excised from the mature transcript. IR in the cosmopolitan free-living amoeba Acanthamoeba castellanii has not been studied. We performed an analysis of RNA sequencing data during encystment to identify genes that presented differentially retained introns during this process. We show that IR increases during cyst formation, indicating a potential mechanism of gene regulation that could help downregulate metabolism. We identify 69 introns from 67 genes that are differentially retained comparing the trophozoite stage and encystment after 24 and 48 h. These genes include several hypothetical proteins. We show different patterns of IR during encystment taking as examples a lipase, a peroxin-3 protein, an Fbox domain containing protein, a proteasome subunit, a polynucleotide adenylyltransferase, and a tetratricopeptide domain containing protein. A better understanding of IR in Acanthamoeba, and even other protists, could help elucidate changes in life cycle and combat disease such as Acanthamoeba keratitis in which the cyst is key for its persistence.
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Affiliation(s)
- Alvaro de Obeso Fernández Del Valle
- Departamento de Bioingeniería, Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, 64849, Monterrey, Mexico.
| | - Jesús Gómez-Montalvo
- Departamento de Bioingeniería, Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, 64849, Monterrey, Mexico
| | - Sutherland K Maciver
- Centre for Discovery Brain Sciences, Edinburgh Medical School, Biomedical Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, Scotland, UK
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21
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Goyal S, Vanita V. A missense mutation in TTC8/BBS8 affecting mRNA splicing in patients with non-syndromic retinitis pigmentosa. Mol Genet Genomics 2022; 297:1439-1449. [PMID: 35939099 DOI: 10.1007/s00438-022-01933-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 07/19/2022] [Indexed: 11/27/2022]
Abstract
Splicing disruption is one type of mutation mechanism for disease-predisposing alleles. To date, less than 30 mutations in TTC8/BBS8 have been reported; however, mutations affecting the splice site are rare. Generally missense mutations are assumed to alter protein function; however, reports have shown that mutations in protein coding exons can disrupt splicing by altering exonic splicing silencer or enhancer motifs. Hence, a missense mutation c.1347G > C (p.Q449H) involving final base of the exon 13 in the TTC8, previously identified by us to be linked with non-syndromic autosomal recessive retinitis pigmentosa (arRP), in an Indian family, that might deleteriously affect splicing has been functionally characterized. RNA was isolated, cDNA prepared and amplified using region-specific primers. PCR products were purified and sequenced bi-directionally by Sanger sequencing. Effect of mutation (c.1347G > C) on mRNA splicing has been predicted using bioinformatics tools. We reported that missense mutation (c.1347G > C) at the last base of exon 13 of TTC8 disrupted the canonical donor splice-site resulting in aberrant RNA splicing. A cryptic donor splice-site got activated 77 bases downstream of the authentic splice donor site in intron 13, resulting in the retention of 77 bases of intron 13, and a frameshift leading to pre-mature termination codon in exon 14 at codon 486. Further, duplication of exon 15 and fusion of its duplicated copy occurred with exon 13. The binding site for SC35 protein, normally involved in splicing, also got disrupted (as predicted by SpliceAid2 software), hence, leading to alternative splicing. Our findings strongly suggest that a missense mutation c.1347G > C in TTC8 disrupted the splice donor site causing retention of 77 bases of intron 13, resulting in a frameshift and subsequently introduced a pre-mature termination codon into exon 14, hence creating an altered mRNA transcript. These findings emphasize the significance of examining missense mutations especially in TTC8, to determine their pathogenic role through alternative splicing. Present findings also reiterate the notion that mutations in the TTC8/BBS8 cause phenotypic heterogeneity and does not always follow Mendelian genetics in this ciliopathy.
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Affiliation(s)
- Shiwali Goyal
- Department of Human Genetics, Guru Nanak Dev University, Amritsar, Punjab, 143005, India
| | - Vanita Vanita
- Department of Human Genetics, Guru Nanak Dev University, Amritsar, Punjab, 143005, India.
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22
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Gualandi N, Iperi C, Esposito M, Ansaloni F, Gustincich S, Sanges R. Meta-Analysis Suggests That Intron Retention Can Affect Quantification of Transposable Elements from RNA-Seq Data. Biology (Basel) 2022; 11:826. [PMID: 35741347 DOI: 10.3390/biology11060826] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/20/2022] [Accepted: 05/26/2022] [Indexed: 02/08/2023]
Abstract
Simple Summary Transposable elements (TEs) are repetitive sequences comprising more than one third of the human genome with the original ability to change their location within the genome. Owing to their repetitive nature, the quantification of TEs results often challenging. RNA-seq is a useful tool for genome-wide TEs quantification, nevertheless it also presents technical issues, including low reads mappability and erroneous quantification derived from the transcription of TEs fragments embedded in canonical transcripts. Fragments derived from TEs are found within the introns of most genes, which led to the hypothesis that intron retention (IR) can affect the unbiased quantification of TEs expression. Performing meta-analysis of public RNA-seq datasets, here we observe that IR can indeed impact the quantification of TEs by increasing the number of reads mapped on intronic TE copies. Our work highlights a correlation between IR and TEs expression measurement by RNA-seq that should be taken into account to achieve reliable TEs quantification, especially in samples characterized by extensive IR, because differential IR might be confused with differential TEs expression. Abstract Transposable elements (TEs), also known as “jumping genes”, are repetitive sequences with the capability of changing their location within the genome. They are key players in many different biological processes in health and disease. Therefore, a reliable quantification of their expression as transcriptional units is crucial to distinguish between their independent expression and the transcription of their sequences as part of canonical transcripts. TEs quantification faces difficulties of different types, the most important one being low reads mappability due to their repetitive nature preventing an unambiguous mapping of reads originating from their sequences. A large fraction of TEs fragments localizes within introns, which led to the hypothesis that intron retention (IR) can be an additional source of bias, potentially affecting accurate TEs quantification. IR occurs when introns, normally removed from the mature transcript by the splicing machinery, are maintained in mature transcripts. IR is a widespread mechanism affecting many different genes with cell type-specific patterns. We hypothesized that, in an RNA-seq experiment, reads derived from retained introns can introduce a bias in the detection of overlapping, independent TEs RNA expression. In this study we performed meta-analysis using public RNA-seq data from lymphoblastoid cell lines and show that IR can impact TEs quantification using established tools with default parameters. Reads mapped on intronic TEs were indeed associated to the expression of TEs and influence their correct quantification as independent transcriptional units. We confirmed these results using additional independent datasets, demonstrating that this bias does not appear in samples where IR is not present and that differential TEs expression does not impact on IR quantification. We concluded that IR causes the over-quantification of intronic TEs and differential IR might be confused with differential TEs expression. Our results should be taken into account for a correct quantification of TEs expression from RNA-seq data, especially in samples in which IR is abundant.
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23
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Wong JJ, Schmitz U. Intron retention: importance, challenges, and opportunities. Trends Genet 2022. [DOI: 10.1016/j.tig.2022.03.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 11/24/2022]
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Qi Y, Ji X, Ding H, Liu L, Zhang Y, Yin A. Novel Biallelic Variant in the BRAT1 Gene Caused Nonprogressive Cerebellar Ataxia Syndrome. Front Genet 2022; 13:821587. [PMID: 35360849 PMCID: PMC8960271 DOI: 10.3389/fgene.2022.821587] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 01/07/2022] [Indexed: 01/13/2023] Open
Abstract
Recessive mutations in BRAT1 cause lethal neonatal rigidity and multifocal seizure syndrome (RMFSL), a phenotype characterized by neonatal microcephaly, hypertonia, and refractory epilepsy with premature death. Recently, attenuated disease variants have been described, suggesting that a wider clinical spectrum of BRAT1-associated neurodegeneration exists than was previously thought. Here, we reported a 10-year-old girl with severe intellectual disability, rigidity, ataxia or dyspraxia, and cerebellar atrophy on brain MRI; two BRAT1 variants in the trans configuration [c.1014A > C (p.Pro338 = ); c.706delC (p.Leu236Cysfs*5)] were detected using whole-exome sequencing. RNA-seq confirmed significantly decreased BRAT1 transcript levels in the presence of the variant; further, it revealed an intron retention between exon 7 and exon 8 caused by the synonymous base substitute. Subsequent prenatal diagnosis for these two variants guided the parents to reproduce. We expand the phenotypic spectrum of BRAT1-associated disorders by first reporting the pathogenic synonymous variant of the BRAT1 gene, resulting in clinical severity that is mild compared to the severe phenotype seen in RMFSL. Making an accurate diagnosis and prognostic evaluation of BRAT1-associated neurodegeneration is important for reproductive consultation and disease management.
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Affiliation(s)
- Yiming Qi
- Prenatal Diagnosis Center, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | - Xueqi Ji
- Prenatal Diagnosis Center, Guangdong Women and Children Hospital, Guangzhou, China,Clinical Medicine College, Guangzhou Medical University, Guangzhou, China
| | - Hongke Ding
- Prenatal Diagnosis Center, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | - Ling Liu
- Prenatal Diagnosis Center, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | - Yan Zhang
- Prenatal Diagnosis Center, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | - Aihua Yin
- Prenatal Diagnosis Center, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China,Clinical Medicine College, Guangzhou Medical University, Guangzhou, China,*Correspondence: Aihua Yin,
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25
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Singh P, Ahi EP. The importance of alternative splicing in adaptive evolution. Mol Ecol 2022; 31:1928-1938. [DOI: 10.1111/mec.16377] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 01/06/2022] [Accepted: 01/25/2022] [Indexed: 11/26/2022]
Affiliation(s)
- Pooja Singh
- Department of Biological Sciences University of Calgary Calgary Canada
- Institute of Ecology and Evolution University of Bern Bern Switzerland
- Swiss Federal Institute of Aquatic Science and Technology (EAWAG) Kastanienbaum Switzerland
| | - Ehsan Pashay Ahi
- Organismal and Evolutionary Biology Research Programme University of Helsinki Helsinki Finland
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26
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Shah JS, Milevskiy MJG, Petrova V, Au AYM, Wong JJL, Visvader JE, Schmitz U, Rasko JEJ. Towards resolution of the intron retention paradox in breast cancer. Breast Cancer Res 2022; 24:100. [PMID: 36581993 PMCID: PMC9798573 DOI: 10.1186/s13058-022-01593-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 12/12/2022] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND After many years of neglect in the field of alternative splicing, the importance of intron retention (IR) in cancer has come into focus following landmark discoveries of aberrant IR patterns in cancer. Many solid and liquid tumours are associated with drastic increases in IR, and such patterns have been pursued as both biomarkers and therapeutic targets. Paradoxically, breast cancer (BrCa) is the only tumour type in which IR is reduced compared to adjacent normal breast tissue. METHODS In this study, we have conducted a pan-cancer analysis of IR with emphasis on BrCa and its subtypes. We explored mechanisms that could cause aberrant and pathological IR and clarified why normal breast tissue has unusually high IR. RESULTS Strikingly, we found that aberrantly decreasing IR in BrCa can be largely attributed to normal breast tissue having the highest occurrence of IR events compared to other healthy tissues. Our analyses suggest that low numbers of IR events in breast tumours are associated with poor prognosis, particularly in the luminal B subtype. Interestingly, we found that IR frequencies negatively correlate with cell proliferation in BrCa cells, i.e. rapidly dividing tumour cells have the lowest number of IR events. Aberrant RNA-binding protein expression and changes in tissue composition are among the causes of aberrantly decreasing IR in BrCa. CONCLUSIONS Our results suggest that IR should be considered for therapeutic manipulation in BrCa patients with aberrantly low IR levels and that further work is needed to understand the cause and impact of high IR in other tumour types.
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Affiliation(s)
- Jaynish S. Shah
- grid.1013.30000 0004 1936 834XComputational BioMedicine Laboratory Centenary Institute, The University of Sydney, Camperdown, Australia ,grid.1013.30000 0004 1936 834XGene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Locked Bag No. 6, Newtown, NSW 2042 Australia ,grid.1002.30000 0004 1936 7857Australian Centre for Blood Diseases, Central Clinical School, Monash University and Alfred Health, Melbourne, VIC Australia
| | - Michael J. G. Milevskiy
- grid.1042.70000 0004 0432 4889ACRF Cancer Biology and Stem Cells Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052 Australia ,grid.1008.90000 0001 2179 088XDepartment of Medical Biology, The University of Melbourne, Parkville, VIC 3010 Australia
| | - Veronika Petrova
- grid.1013.30000 0004 1936 834XComputational BioMedicine Laboratory Centenary Institute, The University of Sydney, Camperdown, Australia ,grid.1013.30000 0004 1936 834XGene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Locked Bag No. 6, Newtown, NSW 2042 Australia
| | - Amy Y. M. Au
- grid.1013.30000 0004 1936 834XGene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Locked Bag No. 6, Newtown, NSW 2042 Australia
| | - Justin J. L. Wong
- grid.1013.30000 0004 1936 834XEpigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown, 2050 Australia ,grid.1013.30000 0004 1936 834XFaculty of Medicine and Health, The University of Sydney, Camperdown, Australia
| | - Jane E. Visvader
- grid.1042.70000 0004 0432 4889ACRF Cancer Biology and Stem Cells Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052 Australia ,grid.1008.90000 0001 2179 088XDepartment of Medical Biology, The University of Melbourne, Parkville, VIC 3010 Australia
| | - Ulf Schmitz
- grid.1013.30000 0004 1936 834XComputational BioMedicine Laboratory Centenary Institute, The University of Sydney, Camperdown, Australia ,grid.1011.10000 0004 0474 1797Department of Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, 1 James Cook Drive, Townsville, QLD 4811 Australia ,grid.1011.10000 0004 0474 1797Centre for Tropical Bioinformatics and Molecular Biology, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, 4878 Australia
| | - John E. J. Rasko
- grid.1013.30000 0004 1936 834XGene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Locked Bag No. 6, Newtown, NSW 2042 Australia ,grid.1013.30000 0004 1936 834XFaculty of Medicine and Health, The University of Sydney, Camperdown, Australia ,grid.413249.90000 0004 0385 0051Cell and Molecular Therapies, Royal Prince Alfred Hospital, Camperdown, Australia
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Kumari A, Sedehizadeh S, Brook JD, Kozlowski P, Wojciechowska M. Differential fates of introns in gene expression due to global alternative splicing. Hum Genet 2021; 141:31-47. [PMID: 34907472 PMCID: PMC8758631 DOI: 10.1007/s00439-021-02409-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 12/02/2021] [Indexed: 02/06/2023]
Abstract
The discovery of introns over four decades ago revealed a new vision of genes and their interrupted arrangement. Throughout the years, it has appeared that introns play essential roles in the regulation of gene expression. Unique processing of excised introns through the formation of lariats suggests a widespread role for these molecules in the structure and function of cells. In addition to rapid destruction, these lariats may linger on in the nucleus or may even be exported to the cytoplasm, where they remain stable circular RNAs (circRNAs). Alternative splicing (AS) is a source of diversity in mature transcripts harboring retained introns (RI-mRNAs). Such RNAs may contain one or more entire retained intron(s) (RIs), but they may also have intron fragments resulting from sequential excision of smaller subfragments via recursive splicing (RS), which is characteristic of long introns. There are many potential fates of RI-mRNAs, including their downregulation via nuclear and cytoplasmic surveillance systems and the generation of new protein isoforms with potentially different functions. Various reports have linked the presence of such unprocessed transcripts in mammals to important roles in normal development and in disease-related conditions. In certain human neurological-neuromuscular disorders, including myotonic dystrophy type 2 (DM2), frontotemporal dementia/amyotrophic lateral sclerosis (FTD/ALS) and Duchenne muscular dystrophy (DMD), peculiar processing of long introns has been identified and is associated with their pathogenic effects. In this review, we discuss different mechanisms involved in the processing of introns during AS and the functions of these large sections of the genome in our biology.
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Affiliation(s)
- Anjani Kumari
- Queen's Medical Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Saam Sedehizadeh
- Queen's Medical Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - John David Brook
- Queen's Medical Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Piotr Kozlowski
- Department of Molecular Genetics, Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznan, Poland
| | - Marzena Wojciechowska
- Department of Molecular Genetics, Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznan, Poland. .,Department of Rare Human Diseases, Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznan, Poland.
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Abstract
Regulation of gene expression plays a central role in adaptive divergence and evolution. Although the role of gene regulation in microevolutionary processes is gaining wide acceptance, most studies have only investigated the evolution of transcript levels, ignoring the potentially significant role of transcript structures. We argue that variation in alternative splicing plays an important and widely unexplored role in adaptation (e.g., by increasing transcriptome and/or proteome diversity, or buffering potentially deleterious genetic variation). New studies increasingly highlight the potential for independent evolution in alternative splicing and transcript level, providing alternative paths for selection to act upon. We propose that alternative splicing and transcript levels can provide contrasting, nonredundant mechanisms of equal importance for adaptive diversification of gene function and regulation.
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Affiliation(s)
- Jukka-Pekka Verta
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Viikinkaari 9, 00790, Helsinki, Finland.
| | - Arne Jacobs
- Institute of Biodiversity, Animal Health, and Comparative Medicine, University of Glasgow, G12 8QQ, Glasgow, UK.
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29
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Abstract
Background Alternative splicing is the process of selecting different combinations of splice sites to produce variably spliced mRNAs. However, the relationships between alternative splicing prevalence and level (ASP/L) and variations of intron size and organism complexity (OC) remain vague. Here, we developed a robust protocol to analyze the relationships between ASP/L and variations of intron size and OC. Approximately 8 Tb raw RNA-Seq data from 37 eumetazoan species were divided into three sets of species based on variations in intron size and OC. Results We found a strong positive correlation between ASP/L and OC, but no correlation between ASP/L and intron size across species. Surprisingly, ASP/L displayed a positive correlation with mean intron size of genes within individual genomes. Moreover, our results revealed that four ASP/L-related pathways contributed to the differences in ASP/L that were associated with OC. In particular, the spliceosome pathway displayed distinct genomic features, such as the highest gene expression level, conservation level, and fraction of disordered regions. Interestingly, lower or no obvious correlations were observed among these genomic features. Conclusions The positive correlation between ASP/L and OC ubiquitously exists in eukaryotes, and this correlation is not affected by the mean intron size of these species. ASP/L-related splicing factors may play an important role in the evolution of OC. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-08172-2.
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Affiliation(s)
- Pengcheng Yang
- Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China
| | - Depin Wang
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing, China
| | - Le Kang
- Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China.
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30
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Song R, Tikoo S, Jain R, Pinello N, Au AY, Nagarajah R, Porse B, Rasko JEJ, Wong JJL. Dynamic intron retention modulates gene expression in the monocytic differentiation pathway. Immunology 2021; 165:274-286. [PMID: 34775600 DOI: 10.1111/imm.13435] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 12/01/2022] Open
Abstract
Monocytes play a crucial role in maintaining homeostasis and mediating a successful innate immune response. They also act as central players in diverse pathological conditions, thus making them an attractive therapeutic target. Within the bone marrow, monocytes arise from a committed precursor termed cMoP (Common Monocyte Progenitor). However, molecular mechanisms that regulate the differentiation of cMoP to various monocytic subsets remain unclear. Herein, we purified murine myeloid precursors for deep poly-A enriched RNA sequencing to understand the role of alternative splicing in the development and differentiation of monocytes under homeostasis. Our analyses revealed intron retention to be the major alternative splicing mechanism involved in the monocyte differentiation cascade, especially in the differentiation of Ly6Chi monocytes to Ly6Clo monocytes. Furthermore, we found that the key genes regulated by intron retention in the differentiation of murine Ly6Chi to Ly6Clo monocytes were also conserved in humans. Our data highlight the unique role of intron retention in the regulation of the monocytic differentiation pathway.
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Affiliation(s)
- Renhua Song
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown, 2050, Australia.,Faculty of Medicine and Health, The University of Sydney, Camperdown, 2050, Australia
| | - Shweta Tikoo
- Faculty of Medicine and Health, The University of Sydney, Camperdown, 2050, Australia.,Immune Imaging Program Centenary Institute, The University of Sydney, Camperdown, 2050, Australia
| | - Rohit Jain
- Faculty of Medicine and Health, The University of Sydney, Camperdown, 2050, Australia.,Immune Imaging Program Centenary Institute, The University of Sydney, Camperdown, 2050, Australia
| | - Natalia Pinello
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown, 2050, Australia.,Faculty of Medicine and Health, The University of Sydney, Camperdown, 2050, Australia
| | - Amy Ym Au
- Faculty of Medicine and Health, The University of Sydney, Camperdown, 2050, Australia.,Gene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, 2050, Australia
| | - Rajini Nagarajah
- Faculty of Medicine and Health, The University of Sydney, Camperdown, 2050, Australia.,Gene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, 2050, Australia
| | - Bo Porse
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.,Biotech Research and Innovation Center (BRIC), University of Copenhagen, 2200, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - John E J Rasko
- Faculty of Medicine and Health, The University of Sydney, Camperdown, 2050, Australia.,Gene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, 2050, Australia.,Cell and Molecular Therapies, Royal Prince Alfred Hospital, Camperdown 2050, Australia
| | - Justin J-L Wong
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown, 2050, Australia.,Faculty of Medicine and Health, The University of Sydney, Camperdown, 2050, Australia
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31
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Navarro E, Mallén A, Hueso M. Dynamic Variations of 3'UTR Length Reprogram the mRNA Regulatory Landscape. Biomedicines 2021; 9:1560. [PMID: 34829789 DOI: 10.3390/biomedicines9111560] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/10/2021] [Accepted: 10/15/2021] [Indexed: 12/16/2022] Open
Abstract
This paper concerns 3′-untranslated regions (3′UTRs) of mRNAs, which are non-coding regulatory platforms that control stability, fate and the correct spatiotemporal translation of mRNAs. Many mRNAs have polymorphic 3′UTR regions. Controlling 3′UTR length and sequence facilitates the regulation of the accessibility of functional effectors (RNA binding proteins, miRNAs or other ncRNAs) to 3′UTR functional boxes and motifs and the establishment of different regulatory landscapes for mRNA function. In this context, shortening of 3′UTRs would loosen miRNA or protein-based mechanisms of mRNA degradation, while 3′UTR lengthening would strengthen accessibility to these effectors. Alterations in the mechanisms regulating 3′UTR length would result in widespread deregulation of gene expression that could eventually lead to diseases likely linked to the loss (or acquisition) of specific miRNA binding sites. Here, we will review the mechanisms that control 3′UTR length dynamics and their alterations in human disorders. We will discuss, from a mechanistic point of view centered on the molecular machineries involved, the generation of 3′UTR variability by the use of alternative polyadenylation and cleavage sites, of mutually exclusive terminal alternative exons (exon skipping) as well as by the process of exonization of Alu cassettes to generate new 3′UTRs with differential functional features.
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32
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Green ID, Liu R, Wong JJL. The Expanding Role of Alternative Splicing in Vascular Smooth Muscle Cell Plasticity. Int J Mol Sci 2021; 22:10213. [PMID: 34638554 DOI: 10.3390/ijms221910213] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/15/2021] [Accepted: 09/18/2021] [Indexed: 12/21/2022] Open
Abstract
Vascular smooth muscle cells (VSMCs) display extraordinary phenotypic plasticity. This allows them to differentiate or dedifferentiate, depending on environmental cues. The ability to ‘switch’ between a quiescent contractile phenotype to a highly proliferative synthetic state renders VSMCs as primary mediators of vascular repair and remodelling. When their plasticity is pathological, it can lead to cardiovascular diseases such as atherosclerosis and restenosis. Coinciding with significant technological and conceptual innovations in RNA biology, there has been a growing focus on the role of alternative splicing in VSMC gene expression regulation. Herein, we review how alternative splicing and its regulatory factors are involved in generating protein diversity and altering gene expression levels in VSMC plasticity. Moreover, we explore how recent advancements in the development of splicing-modulating therapies may be applied to VSMC-related pathologies.
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33
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Wong ACH, Rasko JEJ. Splice and Dice: Intronic microRNAs, Splicing and Cancer. Biomedicines 2021; 9:1268. [PMID: 34572454 DOI: 10.3390/biomedicines9091268] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/13/2021] [Accepted: 09/16/2021] [Indexed: 12/17/2022] Open
Abstract
Introns span only a quarter of the human genome, yet they host around 60% of all known microRNAs. Emerging evidence indicates the adaptive advantage of microRNAs residing within introns is attributed to their complex co-regulation with transcription and alternative splicing of their host genes. Intronic microRNAs are often co-expressed with their host genes, thereby providing functional synergism or antagonism that is exploited or decoupled in cancer. Additionally, intronic microRNA biogenesis and the alternative splicing of host transcript are co-regulated and intertwined. The importance of intronic microRNAs is under-recognized in relation to the pathogenesis of cancer.
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Golicz AA, Allu AD, Li W, Lohani N, Singh MB, Bhalla PL. A dynamic intron retention program regulates the expression of several hundred genes during pollen meiosis. Plant Reprod 2021; 34:225-242. [PMID: 34019149 DOI: 10.1007/s00497-021-00411-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 04/19/2021] [Indexed: 05/12/2023]
Abstract
Intron retention is a stage-specific mechanism of functional attenuation of a subset of co-regulated, functionally related genes during early stages of pollen development. To improve our understanding of the gene regulatory mechanisms that drive developmental processes, we performed a genome-wide study of alternative splicing and isoform switching during five key stages of pollen development in field mustard, Brassica rapa. Surprisingly, for several hundred genes (12.3% of the genes analysed), isoform switching results in stage-specific expression of intron-retaining transcripts at the meiotic stage of pollen development. In such cases, we report temporally regulated switching between expression of a canonical, translatable isoform and an intron-retaining transcript that is predicted to produce a truncated and presumably inactive protein. The results suggest a new pervasive mechanism underlying modulation of protein levels in a plant developmental program. The effect is not based on gene expression induction but on the type of transcript produced. We conclude that intron retention is a stage-specific mechanism of functional attenuation of a subset of co-regulated, functionally related genes during meiosis, especially genes related to ribosome biogenesis, mRNA transport and nuclear envelope architecture. We also propose that stage-specific expression of a non-functional isoform of Brassica rapa BrSDG8, a non-redundant member of histone methyltransferase gene family, linked to alternative splicing regulation, may contribute to the intron retention observed.
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Affiliation(s)
- Agnieszka A Golicz
- Plant Molecular Biology and Biotechnology Laboratory, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Melbourne, VIC, Australia
- Department of Plant Breeding, Justus Liebig University, Giessen, Germany
| | - Annapurna D Allu
- Plant Molecular Biology and Biotechnology Laboratory, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Melbourne, VIC, Australia
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Wei Li
- Plant Molecular Biology and Biotechnology Laboratory, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Melbourne, VIC, Australia
| | - Neeta Lohani
- Plant Molecular Biology and Biotechnology Laboratory, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Melbourne, VIC, Australia
| | - Mohan B Singh
- Plant Molecular Biology and Biotechnology Laboratory, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Melbourne, VIC, Australia
| | - Prem L Bhalla
- Plant Molecular Biology and Biotechnology Laboratory, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Melbourne, VIC, Australia.
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35
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Zhang XS, Yin YS, Wang J, Battaglia T, Krautkramer K, Li WV, Li J, Brown M, Zhang M, Badri MH, Armstrong AJS, Strauch CM, Wang Z, Nemet I, Altomare N, Devlin JC, He L, Morton JT, Chalk JA, Needles K, Liao V, Mount J, Li H, Ruggles KV, Bonneau RA, Dominguez-Bello MG, Bäckhed F, Hazen SL, Blaser MJ. Maternal cecal microbiota transfer rescues early-life antibiotic-induced enhancement of type 1 diabetes in mice. Cell Host Microbe 2021; 29:1249-1265.e9. [PMID: 34289377 PMCID: PMC8370265 DOI: 10.1016/j.chom.2021.06.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 04/27/2021] [Accepted: 06/18/2021] [Indexed: 01/04/2023]
Abstract
Early-life antibiotic exposure perturbs the intestinal microbiota and accelerates type 1 diabetes (T1D) development in the NOD mouse model. Here, we found that maternal cecal microbiota transfer (CMT) to NOD mice after early-life antibiotic perturbation largely rescued the induced T1D enhancement. Restoration of the intestinal microbiome was significant and persistent, remediating the antibiotic-depleted diversity, relative abundance of particular taxa, and metabolic pathways. CMT also protected against perturbed metabolites and normalized innate and adaptive immune effectors. CMT restored major patterns of ileal microRNA and histone regulation of gene expression. Further experiments suggest a gut-microbiota-regulated T1D protection mechanism centered on Reg3γ, in an innate intestinal immune network involving CD44, TLR2, and Reg3γ. This regulation affects downstream immunological tone, which may lead to protection against tissue-specific T1D injury.
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Affiliation(s)
- Xue-Song Zhang
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA; Human Microbiome Program, New York University Langone Medical Center, New York, NY, USA.
| | - Yue Sandra Yin
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA; Human Microbiome Program, New York University Langone Medical Center, New York, NY, USA
| | - Jincheng Wang
- Department of Biochemistry and Microbiology, Rutgers University - New Brunswick, New Brunswick, NJ, USA
| | - Thomas Battaglia
- Human Microbiome Program, New York University Langone Medical Center, New York, NY, USA
| | - Kimberly Krautkramer
- The Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Göteborg 41345, Sweden
| | - Wei Vivian Li
- Department of Biostatistics and Epidemiology, Rutgers University School of Public Health, Piscataway, NJ, USA
| | - Jackie Li
- Human Microbiome Program, New York University Langone Medical Center, New York, NY, USA
| | - Mark Brown
- Cardiovascular & Metabolic Sciences, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA; Center for Microbiome & Human Health, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Meifan Zhang
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA; Human Microbiome Program, New York University Langone Medical Center, New York, NY, USA
| | - Michelle H Badri
- Human Microbiome Program, New York University Langone Medical Center, New York, NY, USA; New York University, Center for Data Science, New York, NY, USA
| | - Abigail J S Armstrong
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA
| | - Christopher M Strauch
- Cardiovascular & Metabolic Sciences, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
| | - Zeneng Wang
- Cardiovascular & Metabolic Sciences, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
| | - Ina Nemet
- Cardiovascular & Metabolic Sciences, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
| | - Nicole Altomare
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA
| | - Joseph C Devlin
- Human Microbiome Program, New York University Langone Medical Center, New York, NY, USA
| | - Linchen He
- Department of Population Health, New York University Langone Medical Center, New York, NY, USA
| | - Jamie T Morton
- Human Microbiome Program, New York University Langone Medical Center, New York, NY, USA; Center for Computational Biology, Flatiron Institute, Simons Foundation, New York, NY, USA
| | - John Alex Chalk
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA
| | - Kelly Needles
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA
| | - Viviane Liao
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA
| | - Julia Mount
- Human Microbiome Program, New York University Langone Medical Center, New York, NY, USA
| | - Huilin Li
- Department of Population Health, New York University Langone Medical Center, New York, NY, USA
| | - Kelly V Ruggles
- Human Microbiome Program, New York University Langone Medical Center, New York, NY, USA
| | - Richard A Bonneau
- Human Microbiome Program, New York University Langone Medical Center, New York, NY, USA; New York University, Center for Data Science, New York, NY, USA; Center for Computational Biology, Flatiron Institute, Simons Foundation, New York, NY, USA
| | - Maria Gloria Dominguez-Bello
- Department of Biochemistry and Microbiology, Rutgers University - New Brunswick, New Brunswick, NJ, USA; Institute for Food, Nutrition and Health, Rutgers University - New Brunswick, New Brunswick, NJ, USA
| | - Fredrik Bäckhed
- The Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Göteborg 41345, Sweden; Region västra Götaland, Sahlgrenska University Hospital, Department of Clinical Physiology, Gothenburg, Sweden; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stanley L Hazen
- Cardiovascular & Metabolic Sciences, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA; Center for Microbiome & Human Health, Cleveland Clinic, Cleveland, OH 44195, USA; Heart, Vascular & Thoracic Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Martin J Blaser
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA; Human Microbiome Program, New York University Langone Medical Center, New York, NY, USA.
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Li C, Feng L, Luo WW, Lei CQ, Li M, Shu HB. The RNA-binding protein LUC7L2 mediates MITA/STING intron retention to negatively regulate innate antiviral response. Cell Discov 2021; 7:46. [PMID: 34155193 PMCID: PMC8217528 DOI: 10.1038/s41421-021-00277-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/22/2021] [Indexed: 11/09/2022] Open
Abstract
MITA (also known as STING) is an ER-located adaptor protein, which mediates DNA-triggered innate immune response and is critically involved in autoimmune diseases and tumorigenesis. MITA is regulated by post-translational modifications, but how post-transcriptional mechanisms are involved in the regulation of MITA is still largely unknown. Here, we identified the RNA-binding protein LUC7L2 as a negative regulator of DNA virus-triggered innate immune response. LUC7L2-deficient mice exhibited resistance to lethal herpes simplex virus 1 (HSV-1) infection and reduced HSV-1 loads in the brain. Mechanistically, LUC7L2 directly bound to intron 3 of MITA precursor messenger RNA, inhibited its splicing and promoted its nonsense-mediated decay, leading to its downregulation at protein level. LUC7L2-deficient cells had markedly increased MITA level, leading to heightened innate antiviral response. Finally, LUC7L2 was induced following HSV-1 infection. Our findings reveal a feedback negative post-transcriptional regulatory mechanism for regulation of MITA-mediated innate immune response to viral and aberrant cellular DNA.
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Affiliation(s)
- Chen Li
- Department of Infectious Diseases, Zhongnan Hospital of Wuhan University, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Research Unit of Innate Immune and Inflammatory Diseases of Chinese Academy of Medical Sciences, Wuhan University, Wuhan, Hubei, China
| | - Lu Feng
- Department of Infectious Diseases, Zhongnan Hospital of Wuhan University, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Research Unit of Innate Immune and Inflammatory Diseases of Chinese Academy of Medical Sciences, Wuhan University, Wuhan, Hubei, China
| | - Wei-Wei Luo
- Wuhan Institute of Virology, Chinese Academy of Sciences, Hubei, Wuhan, China
| | - Cao-Qi Lei
- Department of Infectious Diseases, Zhongnan Hospital of Wuhan University, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Research Unit of Innate Immune and Inflammatory Diseases of Chinese Academy of Medical Sciences, Wuhan University, Wuhan, Hubei, China
| | - Mi Li
- Department of Infectious Diseases, Zhongnan Hospital of Wuhan University, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Research Unit of Innate Immune and Inflammatory Diseases of Chinese Academy of Medical Sciences, Wuhan University, Wuhan, Hubei, China
| | - Hong-Bing Shu
- Department of Infectious Diseases, Zhongnan Hospital of Wuhan University, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Research Unit of Innate Immune and Inflammatory Diseases of Chinese Academy of Medical Sciences, Wuhan University, Wuhan, Hubei, China.
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Yeom KH, Pan Z, Lin CH, Lim HY, Xiao W, Xing Y, Black DL. Tracking pre-mRNA maturation across subcellular compartments identifies developmental gene regulation through intron retention and nuclear anchoring. Genome Res 2021; 31:1106-1119. [PMID: 33832989 PMCID: PMC8168582 DOI: 10.1101/gr.273904.120] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 04/01/2021] [Indexed: 12/24/2022]
Abstract
Steps of mRNA maturation are important gene regulatory events that occur in distinct cellular locations. However, transcriptomic analyses often lose information on the subcellular distribution of processed and unprocessed transcripts. We generated extensive RNA-seq data sets to track mRNA maturation across subcellular locations in mouse embryonic stem cells, neuronal progenitor cells, and postmitotic neurons. We find disparate patterns of RNA enrichment between the cytoplasmic, nucleoplasmic, and chromatin fractions, with some genes maintaining more polyadenylated RNA in chromatin than in the cytoplasm. We bioinformatically defined four regulatory groups for intron retention, including complete cotranscriptional splicing, complete intron retention in the cytoplasmic RNA, and two intron groups present in nuclear and chromatin transcripts but fully excised in cytoplasm. We found that introns switch their regulatory group between cell types, including neuronally excised introns repressed by polypyrimidine track binding protein 1 (PTBP1). Transcripts for the neuronal gamma-aminobutyric acid (GABA) B receptor, 1 (Gabbr1) are highly expressed in mESCs but are absent from the cytoplasm. Instead, incompletely spliced Gabbr1 RNA remains sequestered on chromatin, where it is bound by PTBP1, similar to certain long noncoding RNAs. Upon neuronal differentiation, Gabbr1 RNA becomes fully processed and exported for translation. Thus, splicing repression and chromatin anchoring of RNA combine to allow posttranscriptional regulation of Gabbr1 over development. For this and other genes, polyadenylated RNA abundance does not indicate functional gene expression. Our data sets provide a rich resource for analyzing many other aspects of mRNA maturation in subcellular locations and across development.
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Affiliation(s)
- Kyu-Hyeon Yeom
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Zhicheng Pan
- Bioinformatics Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, California 90095, USA.,Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Chia-Ho Lin
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Han Young Lim
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA.,Molecular Biology Interdepartmental Doctoral Program, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Wen Xiao
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Yi Xing
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Douglas L Black
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
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Lee VV, Judd LM, Jex AR, Holt KE, Tonkin CJ, Ralph SA. Direct Nanopore Sequencing of mRNA Reveals Landscape of Transcript Isoforms in Apicomplexan Parasites. mSystems 2021; 6:e01081-20. [PMID: 33688018 DOI: 10.1128/mSystems.01081-20] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Alternative splicing is a widespread phenomenon in metazoans by which single genes are able to produce multiple isoforms of the gene product. However, this has been poorly characterized in apicomplexans, a major phylum of some of the most important global parasites. Efforts have been hampered by atypical transcriptomic features, such as the high AU content of Plasmodium RNA, but also the limitations of short-read sequencing in deciphering complex splicing events. In this study, we utilized the long read direct RNA sequencing platform developed by Oxford Nanopore Technologies to survey the alternative splicing landscape of Toxoplasma gondii and Plasmodium falciparum. We find that while native RNA sequencing has a reduced throughput, it allows us to obtain full-length or nearly full-length transcripts with comparable quantification to Illumina sequencing. By comparing these data with available gene models, we find widespread alternative splicing, particularly intron retention, in these parasites. Most of these transcripts contain premature stop codons, suggesting that in these parasites, alternative splicing represents a pathway to transcriptomic diversity, rather than expanding proteomic diversity. Moreover, alternative splicing rates are comparable between parasites, suggesting a shared splicing machinery, despite notable transcriptomic differences between the parasites. This study highlights a strategy in using long-read sequencing to understand splicing events at the whole-transcript level and has implications in the future interpretation of transcriptome sequencing studies. IMPORTANCE We have used a novel nanopore sequencing technology to directly analyze parasite transcriptomes. The very long reads of this technology reveal the full-length genes of the parasites that cause malaria and toxoplasmosis. Gene transcripts must be processed in a process called splicing before they can be translated to protein. Our analysis reveals that these parasites very frequently only partially process their gene products, in a manner that departs dramatically from their human hosts.
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Ma H, Han YC, Palti Y, Gao G, Liu S, Palmquist DE, Wiens GD, Shepherd BS. Structure and regulation of the NK-lysin (1-4) and NK-lysin like (a and b) antimicrobial genes in rainbow trout (Oncorhynchus mykiss). Dev Comp Immunol 2021; 116:103961. [PMID: 33301795 DOI: 10.1016/j.dci.2020.103961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/03/2020] [Accepted: 12/03/2020] [Indexed: 06/12/2023]
Abstract
Nk-lysin (Nkl), an antimicrobial peptide (AMP) product of natural killer cells and cytotoxic T cells in mammals, has recently been characterized in a number of finfish species. In this study, we identified six genes with sequence homology to Nkl and characterized their patterns of mRNA expression and abundances in rainbow trout (Oncorhynchus mykiss). The cDNA sequences for the six Nkls encoded precursor peptides of 128-133 aa in length, and mature peptides of 109-111 aa in length. Genomic DNA of the nkl1-4 genes consisted of five exons and four introns, whereas the nkl-like a & b genes consisted of four exons and three introns. Chromosomal locations of these peptides show that nkl1 was located on chromosome arm 25q, whereas the other five nkl genes were clustered on chromosome arm 19q. Phylogenetic analysis revealed a conserved structure of Nkls among the teleosts and further protein sequence analyses suggests that all six nkl genes fall within the Nkl sub-family of the Saposin family of proteins. Patterns of tissue-specific mRNA expression were asymmetric among the six trout Nkl homologues, with nkl1, nkl3, and nkl-like a & b occurring in immune competent organs such as spleen, gill, intestine and kidney, as well as pineal gland, brain and oocytes. However, nkl2 and nkl4, showed primary abundances in brain, pineal gland and oocyte tissues. Using mRNA sequencing, in whole-body pools of juvenile trout fry (1 g bw) exposed to Flavobacterium psychrophilum infection, we observed modest up-regulation (2-3 fold) of five (nkl 2-4 and nkl-like a & b) of the six nkl mRNAs over the five-day post-challenge time-course. However, no upregulation could be recorded in spleen tissue measured by qPCR in juvenile trout (270 g bw). Using mRNA sequencing again, mRNA abundances were determined in gill of juvenile trout (~57.7 g bw) exposed to various aquaculture stressors. The results indicated that all six nkls (nkl1-4 and nkl-like a and nkl-like b) were downregulated when exposed to high temperature, and that nkl1 was significantly downregulated following salinity challenge. Overall, these newly characterized AMPs may contribute to host innate immunity as they are modulated following pathogen challenge and by physiological stressors.
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Affiliation(s)
- Hao Ma
- USDA-ARS-NADC-Ruminant Diseases and Immunology Research Unit, 1920 Dayton Ave, Ames, IA, 50010, USA; USDA-ARS-National Center for Cool and Cold Water Aquaculture, 11861 Leetown Rd., Leetown, WV, 25430, USA
| | - Yueh-Chiang Han
- USDA-ARS-School of Freshwater Sciences, 600 E. Greenfield Ave., Milwaukee, WI, 53204, USA
| | - Yniv Palti
- USDA-ARS-National Center for Cool and Cold Water Aquaculture, 11861 Leetown Rd., Leetown, WV, 25430, USA
| | - Guangtu Gao
- USDA-ARS-National Center for Cool and Cold Water Aquaculture, 11861 Leetown Rd., Leetown, WV, 25430, USA
| | - Sixin Liu
- USDA-ARS-National Center for Cool and Cold Water Aquaculture, 11861 Leetown Rd., Leetown, WV, 25430, USA
| | - Debra E Palmquist
- USDA/ARS-Midwest Area Statistics Unit, 1815 N. Street, Peoria, IL, 61604, USA
| | - Gregory D Wiens
- USDA-ARS-National Center for Cool and Cold Water Aquaculture, 11861 Leetown Rd., Leetown, WV, 25430, USA
| | - Brian S Shepherd
- USDA-ARS-School of Freshwater Sciences, 600 E. Greenfield Ave., Milwaukee, WI, 53204, USA.
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Abstract
Bicistronic transcripts (operon-like transcripts) have occasionally been reported in eukaryotes, including unicellular yeasts, plants, and humans, despite the fact that they lack trans-splice mechanisms. However, the characteristics of eukaryotic bicistronic transcripts are poorly understood, except for those in nematodes. Here, we describe the genomic, transcriptomic, and ribosome profiling features of bicistronic transcripts in unicellular yeasts. By comparing the expression level of bicistronic transcripts with their monocistronic equivalents, we identify two main categories of bicistronic transcripts: highly and lowly expressed. These two categories exhibit quite different features. First, highly expressed bicistronic transcripts have higher conservation within and between strains and shorter intergenic spacers with higher GC content and less stable secondary structure. Second, genes in highly expressed bicistronic transcripts have lower translation efficiency, with the second gene showing statistically significant lower translation efficiency than the first. Finally, the genes found in these highly expressed bicistronic transcripts tend to be younger, with more recent origins. Together, these results suggest that bicistronic transcripts in yeast are heterogeneous. We further propose that at least some highly expressed bicistronic transcripts appear to play a role in modulating monocistronic translation.IMPORTANCE Operons, where a single mRNA transcript encodes multiple adjacent proteins, are a widespread feature of bacteria and archaea. In contrast, the genes of eukaryotes are generally considered monocistronic. However, a number of studies have revealed the presence of bicistronic transcripts in eukaryotes, including humans. The basic features of these transcripts are largely unknown in eukaryotes, especially in organisms lacking trans-splice mechanisms. Our analyses characterize bicistronic transcripts in one such eukaryotic group, yeasts. We show that highly expressed bicistronic transcripts have unusual features compared to lowly expressed bicistronic transcripts, with several features influencing translational modulation.
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Xue X, Suvorov A, Fujimoto S, Dilman AR, Adams BJ. Genome analysis of Plectus murrayi, a nematode from continental Antarctica. G3 (Bethesda) 2021; 11:6044189. [PMID: 33561244 PMCID: PMC8022722 DOI: 10.1093/g3journal/jkaa045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/08/2020] [Indexed: 01/23/2023]
Abstract
Plectus murrayi is one of the most common and locally abundant invertebrates of continental Antarctic ecosystems. Because it is readily cultured on artificial medium in the laboratory and highly tolerant to an extremely harsh environment, P. murrayi is emerging as a model organism for understanding the evolutionary origin and maintenance of adaptive responses to multiple environmental stressors, including freezing and desiccation. The de novo assembled genome of P. murrayi contains 225.741 million base pairs and a total of 14,689 predicted genes. Compared to Caenorhabditis elegans, the architectural components of P. murrayi are characterized by a lower number of protein-coding genes, fewer transposable elements, but more exons, than closely related taxa from less harsh environments. We compared the transcriptomes of lab-reared P. murrayi with wild-caught P. murrayi and found genes involved in growth and cellular processing were up-regulated in lab-cultured P. murrayi, while a few genes associated with cellular metabolism and freeze tolerance were expressed at relatively lower levels. Preliminary comparative genomic and transcriptomic analyses suggest that the observed constraints on P. murrayi genome architecture and functional gene expression, including genome decay and intron retention, may be an adaptive response to persisting in a biotically simplified, yet consistently physically harsh environment.
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Affiliation(s)
- Xia Xue
- Precision Medicine Center, Academy of Medical Sciences, Zhengzhou University, Zhengzhou 450000, China.,Department of Biology, Evolutionary Ecology Laboratories, and Monte L. Bean Museum, Brigham Young University, Provo, UT, USA
| | - Anton Suvorov
- Department of Biology, Evolutionary Ecology Laboratories, and Monte L. Bean Museum, Brigham Young University, Provo, UT, USA
| | - Stanley Fujimoto
- Department of Computer Science, Brigham Young University, Provo, UT, USA
| | - Adler R Dilman
- Department of Nematology, University of California, Riverside, CA, USA
| | - Byron J Adams
- Department of Biology, Evolutionary Ecology Laboratories, and Monte L. Bean Museum, Brigham Young University, Provo, UT, USA
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Martín G, Márquez Y, Mantica F, Duque P, Irimia M. Alternative splicing landscapes in Arabidopsis thaliana across tissues and stress conditions highlight major functional differences with animals. Genome Biol 2021; 22:35. [PMID: 33446251 PMCID: PMC7807721 DOI: 10.1186/s13059-020-02258-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 12/22/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Alternative splicing (AS) is a widespread regulatory mechanism in multicellular organisms. Numerous transcriptomic and single-gene studies in plants have investigated AS in response to specific conditions, especially environmental stress, unveiling substantial amounts of intron retention that modulate gene expression. However, a comprehensive study contrasting stress-response and tissue-specific AS patterns and directly comparing them with those of animal models is still missing. RESULTS We generate a massive resource for Arabidopsis thaliana, PastDB, comprising AS and gene expression quantifications across tissues, development and environmental conditions, including abiotic and biotic stresses. Harmonized analysis of these datasets reveals that A. thaliana shows high levels of AS, similar to fruitflies, and that, compared to animals, disproportionately uses AS for stress responses. We identify core sets of genes regulated specifically by either AS or transcription upon stresses or among tissues, a regulatory specialization that is tightly mirrored by the genomic features of these genes. Unexpectedly, non-intron retention events, including exon skipping, are overrepresented across regulated AS sets in A. thaliana, being also largely involved in modulating gene expression through NMD and uORF inclusion. CONCLUSIONS Non-intron retention events have likely been functionally underrated in plants. AS constitutes a distinct regulatory layer controlling gene expression upon internal and external stimuli whose target genes and master regulators are hardwired at the genomic level to specifically undergo post-transcriptional regulation. Given the higher relevance of AS in the response to different stresses when compared to animals, this molecular hardwiring is likely required for a proper environmental response in A. thaliana.
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Affiliation(s)
- Guiomar Martín
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, 2780-156, Oeiras, Portugal.
| | - Yamile Márquez
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Dr. Aiguader, 88, Barcelona, 08003, Spain
| | - Federica Mantica
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Dr. Aiguader, 88, Barcelona, 08003, Spain
| | - Paula Duque
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, 2780-156, Oeiras, Portugal
| | - Manuel Irimia
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Dr. Aiguader, 88, Barcelona, 08003, Spain. .,Universitat Pompeu Fabra, Dr. Aiguader, 88, Barcelona, 08003, Spain. .,ICREA, Passeig de Lluís Companys, 23, 08010, Barcelona, Spain.
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Ibrahim HM, Kusch S, Didelon M, Raffaele S. Genome-wide alternative splicing profiling in the fungal plant pathogen Sclerotinia sclerotiorum during the colonization of diverse host families. Mol Plant Pathol 2021; 22:31-47. [PMID: 33111422 PMCID: PMC7749757 DOI: 10.1111/mpp.13006] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/16/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
Sclerotinia sclerotiorum is a notorious generalist plant pathogen that threatens more than 600 host plants, including wild and cultivated species. The molecular bases underlying the broad compatibility of S. sclerotiorum with its hosts is not fully elucidated. In contrast to higher plants and animals, alternative splicing (AS) is not well studied in plant-pathogenic fungi. AS is a common regulated cellular process that increases cell protein and RNA diversity. In this study, we annotated spliceosome genes in the genome of S. sclerotiorum and characterized their expression in vitro and during the colonization of six host species. Several spliceosome genes were differentially expressed in planta, suggesting that AS was altered during infection. Using stringent parameters, we identified 1,487 S. sclerotiorum genes differentially expressed in planta and exhibiting alternative transcripts. The most common AS events during the colonization of all plants were retained introns and the alternative 3' receiver site. We identified S. sclerotiorum genes expressed in planta for which (a) the relative accumulation of alternative transcripts varies according to the host being colonized and (b) alternative transcripts harbour distinct protein domains. This notably included 42 genes encoding predicted secreted proteins showing high-confidence AS events. This study indicates that AS events are taking place in the plant pathogenic fungus S. sclerotiorum during the colonization of host plants and could generate functional diversity in the repertoire of proteins secreted by S. sclerotiorum during infection.
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Affiliation(s)
- Heba M.M. Ibrahim
- LIPM, Université de ToulouseINRAECNRSCastanet‐TolosanFrance
- Genetics DepartmentFaculty of AgricultureCairo UniversityGizaEgypt
- Present address:
Plant Health and ProtectionDivision of Plant BiotechnicsDepartment of BiosystemsFaculty of Bioscience EngineeringKU LeuvenLeuvenBelgium
| | - Stefan Kusch
- LIPM, Université de ToulouseINRAECNRSCastanet‐TolosanFrance
- Present address:
Unit of Plant Molecular Cell BiologyInstitute for Biology IRWTH Aachen UniversityAachenGermany
| | - Marie Didelon
- LIPM, Université de ToulouseINRAECNRSCastanet‐TolosanFrance
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Schmitz U, Monteuuis G, Petrova V, Shah JS, Rasko JE. Computational Methods for Intron Retention Identification and Quantification. Systems Medicine 2021. [DOI: 10.1016/b978-0-12-801238-3.11567-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Velandia-Piedrahita CA, Morel A, Fonseca-Mendoza DJ, Huertas-Quiñones VM, Castillo D, Bonilla JD, Hernandez-Toro CJ, Miranda-Fernández MC, Restrepo CM, Cabrera R. A Novel Splice-Site Mutation in the ELN Gene Suggests an Alternative Mechanism for Vascular Elastinopathies. Appl Clin Genet 2020; 13:233-240. [PMID: 33364810 PMCID: PMC7751611 DOI: 10.2147/tacg.s282240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/03/2020] [Indexed: 11/23/2022]
Abstract
The ELN gene encodes elastin, a fundamental protein of the extracellular matrix that confers elasticity to different tissues including blood vessels. The formation of elastin fibers is a complex process involving monomer coacervation and subsequent crosslinking. Mutations in exons 1-29 of the ELN gene have been linked to supravalvular aortic stenosis (SVAS) whereas mutations in exons 30-33 are associated with autosomal dominant cutis laxa (ADCL). This striking segregation has led to the hypothesis that distinct molecular mechanisms underlie both diseases. SVAS is believed to arise through haploinsufficiency while ADCL is hypothesized to be caused by a dominant negative effect. Here, we describe a patient with SVAS harboring a novel splice-site mutation in the last exon of ELN. The location of this mutation is not consistent with current knowledge of SVAS, since all mutations reported in the C-terminus have been found in ADCL patients, and a thorough evaluation did not reveal significant skin involvement in this case. RT-PCR analysis of skin tissue showed that C-terminal mutations in the region can lead to the production of aberrant transcripts through intron retention and activation of cryptic splice sites and suggest that disruption of the very last exon can lead to functional haploinsufficiency potentially related to SVAS.
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Affiliation(s)
- Camilo Andres Velandia-Piedrahita
- Laboratorio de Biología Molecular y Pruebas Diagnósticas de Alta Complejidad, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá, Colombia
| | - Adrien Morel
- Center for Research in Genetics and Genomics-CIGGUR, GENIUROS Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Dora Janeth Fonseca-Mendoza
- Center for Research in Genetics and Genomics-CIGGUR, GENIUROS Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Victor Manuel Huertas-Quiñones
- Instituto de Cardiopatías Congénitas, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá, Colombia.,Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, Colombia.,Facultad de Medicina, Universidad del Rosario, Bogotá, Colombia
| | - David Castillo
- Servicio de Dermatología, Fundación Para la Investigación en Dermatología FUNINDERMA, Bogotá, Colombia
| | | | - Camilo José Hernandez-Toro
- Laboratorio de Biología Molecular y Pruebas Diagnósticas de Alta Complejidad, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá, Colombia
| | - Marta Catalina Miranda-Fernández
- Laboratorio de Biología Molecular y Pruebas Diagnósticas de Alta Complejidad, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá, Colombia
| | - Carlos Martin Restrepo
- Center for Research in Genetics and Genomics-CIGGUR, GENIUROS Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Rodrigo Cabrera
- Laboratorio de Biología Molecular y Pruebas Diagnósticas de Alta Complejidad, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá, Colombia.,Center for Research in Genetics and Genomics-CIGGUR, GENIUROS Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
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Schmitz U, Shah JS, Dhungel BP, Monteuuis G, Luu PL, Petrova V, Metierre C, Nair SS, Bailey CG, Saunders VA, Turhan AG, White DL, Branford S, Clark SJ, Hughes TP, Wong JJL, Rasko JE. Widespread Aberrant Alternative Splicing despite Molecular Remission in Chronic Myeloid Leukaemia Patients. Cancers (Basel) 2020; 12:cancers12123738. [PMID: 33322625 PMCID: PMC7764299 DOI: 10.3390/cancers12123738] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/11/2022] Open
Abstract
Simple Summary This study provides new insights into the changing transcriptomic and epigenomic landscapes in chronic myeloid leukaemia (CML) patients who are receiving tyrosine kinase inhibitor (TKI) therapy (often life-long). Alternative splicing, vital for cellular homeostasis, is dysregulated in human cancers. Remarkably, we found abnormal splicing patterns despite molecular remission in peripheral blood cells of chronic-phase CML patients. This phenomenon is independent of the TKI drug used and in striking contrast to the normalisation of gene expression and DNA methylation patterns. Abstract Vast transcriptomics and epigenomics changes are characteristic of human cancers, including leukaemia. At remission, we assume that these changes normalise so that omics-profiles resemble those of healthy individuals. However, an in-depth transcriptomic and epigenomic analysis of cancer remission has not been undertaken. A striking exemplar of targeted remission induction occurs in chronic myeloid leukaemia (CML) following tyrosine kinase inhibitor (TKI) therapy. Using RNA sequencing and whole-genome bisulfite sequencing, we profiled samples from chronic-phase CML patients at diagnosis and remission and compared these to healthy donors. Remarkably, our analyses revealed that abnormal splicing distinguishes remission samples from normal controls. This phenomenon is independent of the TKI drug used and in striking contrast to the normalisation of gene expression and DNA methylation patterns. Most remarkable are the high intron retention (IR) levels that even exceed those observed in the diagnosis samples. Increased IR affects cell cycle regulators at diagnosis and splicing regulators at remission. We show that aberrant splicing in CML is associated with reduced expression of specific splicing factors, histone modifications and reduced DNA methylation. Our results provide novel insights into the changing transcriptomic and epigenomic landscapes of CML patients during remission. The conceptually unanticipated observation of widespread aberrant alternative splicing after remission induction warrants further exploration. These results have broad implications for studying CML relapse and treating minimal residual disease.
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Affiliation(s)
- Ulf Schmitz
- Computational BioMedicine Laboratory Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia; (U.S.); (V.P.)
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia; (J.S.S.); (B.P.D.); (G.M.); (C.M.); (C.G.B.)
- Faculty of Medicine & Health, The University of Sydney, Camperdown, NSW 2050, Australia;
| | - Jaynish S. Shah
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia; (J.S.S.); (B.P.D.); (G.M.); (C.M.); (C.G.B.)
- Faculty of Medicine & Health, The University of Sydney, Camperdown, NSW 2050, Australia;
| | - Bijay P. Dhungel
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia; (J.S.S.); (B.P.D.); (G.M.); (C.M.); (C.G.B.)
- Faculty of Medicine & Health, The University of Sydney, Camperdown, NSW 2050, Australia;
| | - Geoffray Monteuuis
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia; (J.S.S.); (B.P.D.); (G.M.); (C.M.); (C.G.B.)
| | - Phuc-Loi Luu
- Epigenetics Research Laboratory, Genomics and Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia; (P.-L.L.); (S.J.C.)
| | - Veronika Petrova
- Computational BioMedicine Laboratory Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia; (U.S.); (V.P.)
| | - Cynthia Metierre
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia; (J.S.S.); (B.P.D.); (G.M.); (C.M.); (C.G.B.)
| | - Shalima S. Nair
- Kinghorn Centre for Clinical Genomics Core Facility, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia;
- St Vincent’s Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, NSW 2010, Australia
| | - Charles G. Bailey
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia; (J.S.S.); (B.P.D.); (G.M.); (C.M.); (C.G.B.)
- Faculty of Medicine & Health, The University of Sydney, Camperdown, NSW 2050, Australia;
| | - Verity A. Saunders
- Cancer Program, Precision Medicine Theme, South Australian Health & Medical Research Institute, Adelaide, SA 50000, Australia; (V.A.S.); (D.L.W.)
| | - Ali G. Turhan
- APHP, Division of Hematology, Paris Sud University Hospitals and Inserm U935 INGESTEM Pluripotent Stem Cell Infrastructure 78 Rue du Général Leclerc, 94275 Le Kremlin Bicetre, France;
| | - Deborah L. White
- Cancer Program, Precision Medicine Theme, South Australian Health & Medical Research Institute, Adelaide, SA 50000, Australia; (V.A.S.); (D.L.W.)
- School of Medicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5000, Australia; (S.B.); (T.P.H.)
- Australasian Leukaemia and Lymphoma Group, Richmond, VIC 3121, Australia
- School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA 5000, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA 5000, Australia
| | - Susan Branford
- School of Medicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5000, Australia; (S.B.); (T.P.H.)
- School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA 5000, Australia
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA 5000, Australia
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
| | - Susan J. Clark
- Epigenetics Research Laboratory, Genomics and Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia; (P.-L.L.); (S.J.C.)
- St Vincent’s Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia
| | - Timothy P. Hughes
- School of Medicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5000, Australia; (S.B.); (T.P.H.)
- Australasian Leukaemia and Lymphoma Group, Richmond, VIC 3121, Australia
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
- Department of Haematology, Centre for Cancer Biology, SA Pathology, Adelaide, SA 5001, Australia
| | - Justin J.-L. Wong
- Faculty of Medicine & Health, The University of Sydney, Camperdown, NSW 2050, Australia;
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
| | - John E.J. Rasko
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia; (J.S.S.); (B.P.D.); (G.M.); (C.M.); (C.G.B.)
- Faculty of Medicine & Health, The University of Sydney, Camperdown, NSW 2050, Australia;
- Cell and Molecular Therapies, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia
- Correspondence: ; Tel.: +61-2-9565-6160
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Meurer SK, Weiskirchen R. Endoglin: An 'Accessory' Receptor Regulating Blood Cell Development and Inflammation. Int J Mol Sci 2020; 21:E9247. [PMID: 33287465 DOI: 10.3390/ijms21239247] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/01/2020] [Accepted: 12/02/2020] [Indexed: 12/13/2022] Open
Abstract
Transforming growth factor-β1 (TGF-β1) is a pleiotropic factor sensed by most cells. It regulates a broad spectrum of cellular responses including hematopoiesis. In order to process TGF-β1-responses in time and space in an appropriate manner, there is a tight regulation of its signaling at diverse steps. The downstream signaling is mediated by type I and type II receptors and modulated by the ‘accessory’ receptor Endoglin also termed cluster of differentiation 105 (CD105). Endoglin was initially identified on pre-B leukemia cells but has received most attention due to its high expression on activated endothelial cells. In turn, Endoglin has been figured out as the causative factor for diseases associated with vascular dysfunction like hereditary hemorrhagic telangiectasia-1 (HHT-1), pre-eclampsia, and intrauterine growth restriction (IUPR). Because HHT patients often show signs of inflammation at vascular lesions, and loss of Endoglin in the myeloid lineage leads to spontaneous inflammation, it is speculated that Endoglin impacts inflammatory processes. In line, Endoglin is expressed on progenitor/precursor cells during hematopoiesis as well as on mature, differentiated cells of the innate and adaptive immune system. However, so far only pro-monocytes and macrophages have been in the focus of research, although Endoglin has been identified in many other immune system cell subsets. These findings imply a functional role of Endoglin in the maturation and function of immune cells. Aside the functional relevance of Endoglin in endothelial cells, CD105 is differentially expressed during hematopoiesis, arguing for a role of this receptor in the development of individual cell lineages. In addition, Endoglin expression is present on mature immune cells of the innate (i.e., macrophages and mast cells) and the adaptive (i.e., T-cells) immune system, further suggesting Endoglin as a factor that shapes immune responses. In this review, we summarize current knowledge on Endoglin expression and function in hematopoietic precursors and mature hematopoietic cells of different lineages.
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48
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Yao J, Ding D, Li X, Shen T, Fu H, Zhong H, Wei G, Ni T. Prevalent intron retention fine-tunes gene expression and contributes to cellular senescence. Aging Cell 2020; 19:e13276. [PMID: 33274830 PMCID: PMC7744961 DOI: 10.1111/acel.13276] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/24/2020] [Accepted: 10/18/2020] [Indexed: 12/20/2022] Open
Abstract
Intron retention (IR) is the least well‐understood alternative splicing type in animals, and its prevalence and function in physiological and pathological processes have long been underestimated. Cellular senescence contributes to individual aging and age‐related diseases and can also serve as an important cancer prevention mechanism. Dynamic IR events have been observed in senescence models and aged tissues; however, whether and how IR impacts senescence remain unclear. Through analyzing polyA+ RNA‐seq data from human replicative senescence models, we found IR was prevalent and dynamically regulated during senescence and IR changes negatively correlated with expression alteration of corresponding genes. We discovered that knocking down (KD) splicing factor U2AF1, which showed higher binding density to retained introns and decreased expression during senescence, led to senescence‐associated phenotypes and global IR changes. Intriguingly, U2AF1‐KD‐induced IR changes also negatively correlated with gene expression. Furthermore, we demonstrated that U2AF1‐mediated IR of specific gene (CPNE1 as an example) contributed to cellular senescence. Decreased expression of U2AF1, higher IR of CPNE1, and reduced expression of CPNE1 were also discovered in dermal fibroblasts with age. We discovered prevalent IR could fine‐tune gene expression and contribute to senescence‐associated phenotypes, largely extending the biological significance of IR.
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Affiliation(s)
- Jun Yao
- State Key Laboratory of Genetic Engineering Collaborative Innovation Center of Genetics and Development Human Phenome Institute School of Life Sciences Fudan University Shanghai P.R. China
| | - Dong Ding
- State Key Laboratory of Genetic Engineering Collaborative Innovation Center of Genetics and Development Human Phenome Institute School of Life Sciences Fudan University Shanghai P.R. China
| | - Xueping Li
- State Key Laboratory of Genetic Engineering Collaborative Innovation Center of Genetics and Development Human Phenome Institute School of Life Sciences Fudan University Shanghai P.R. China
| | - Ting Shen
- State Key Laboratory of Genetic Engineering Collaborative Innovation Center of Genetics and Development Human Phenome Institute School of Life Sciences Fudan University Shanghai P.R. China
| | - Haihui Fu
- State Key Laboratory of Genetic Engineering Collaborative Innovation Center of Genetics and Development Human Phenome Institute School of Life Sciences Fudan University Shanghai P.R. China
| | - Hua Zhong
- Department of Population Health NYU Langone School of Medicine New York NY USA
| | - Gang Wei
- State Key Laboratory of Genetic Engineering Collaborative Innovation Center of Genetics and Development Human Phenome Institute School of Life Sciences Fudan University Shanghai P.R. China
| | - Ting Ni
- State Key Laboratory of Genetic Engineering Collaborative Innovation Center of Genetics and Development Human Phenome Institute School of Life Sciences Fudan University Shanghai P.R. China
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49
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Bogard B, Francastel C, Hubé F. Multiple information carried by RNAs: total eclipse or a light at the end of the tunnel? RNA Biol 2020; 17:1707-1720. [PMID: 32559119 PMCID: PMC7714488 DOI: 10.1080/15476286.2020.1783868] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/06/2020] [Accepted: 06/12/2020] [Indexed: 12/14/2022] Open
Abstract
The findings that an RNA is not necessarily either coding or non-coding, or that a precursor RNA can produce different types of mature RNAs, whether coding or non-coding, long or short, have challenged the dichotomous view of the RNA world almost 15 years ago. Since then, and despite an increasing number of studies, the diversity of information that can be conveyed by RNAs is rarely searched for, and when it is known, it remains largely overlooked in further functional studies. Here, we provide an update with prominent examples of multiple functions that are carried by the same RNA or are produced by the same precursor RNA, to emphasize their biological relevance in most living organisms. An important consequence is that the overall function of their locus of origin results from the balance between various RNA species with distinct functions and fates. The consideration of the molecular basis of this multiplicity of information is obviously crucial for downstream functional studies when the targeted functional molecule is often not the one that is believed.
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Affiliation(s)
- Baptiste Bogard
- Université De Paris, Epigenetics and Cell Fate, CNRS, Paris, France
| | | | - Florent Hubé
- Université De Paris, Epigenetics and Cell Fate, CNRS, Paris, France
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50
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Grabski DF, Broseus L, Kumari B, Rekosh D, Hammarskjold ML, Ritchie W. Intron retention and its impact on gene expression and protein diversity: A review and a practical guide. Wiley Interdiscip Rev RNA 2020; 12:e1631. [PMID: 33073477 DOI: 10.1002/wrna.1631] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 09/16/2020] [Accepted: 09/23/2020] [Indexed: 12/12/2022]
Abstract
Intron retention (IR) occurs when a complete and unspliced intron remains in mature mRNA. An increasing body of literature has demonstrated a major role for IR in numerous biological functions, including several that impact human health and disease. Although experimental technologies used to study other forms of mRNA splicing can also be used to investigate IR, a specialized downstream computational analysis is optimal for IR discovery and analysis. Here we provide a review of IR and its biological implications, as well as a practical guide for how to detect and analyze it. Several methods, including long read third generation direct RNA sequencing, are described. We have developed an R package, FakIR, to facilitate the execution of the bioinformatic tasks recommended in this review and a tutorial on how to fit them to users aims. Additionally, we provide guidelines and experimental protocols to validate IR discovery and to evaluate the potential impact of IR on gene expression and protein output. This article is categorized under: RNA Evolution and Genomics > Computational Analyses of RNA RNA Processing > Splicing Regulation/Alternative Splicing RNA Methods > RNA Analyses in vitro and In Silico.
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Affiliation(s)
- David F Grabski
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Myles H. Thaler Center for AIDS and Human Retrovirus Research, University of Virginia, Charlottesville, Virginia, USA
| | - Lucile Broseus
- IGH, Centre National de la Recherche Scientifique, University of Montpellier, Montpellier, France
| | - Bandana Kumari
- IGH, Centre National de la Recherche Scientifique, University of Montpellier, Montpellier, France
| | - David Rekosh
- Myles H. Thaler Center for AIDS and Human Retrovirus Research, University of Virginia, Charlottesville, Virginia, USA.,Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Marie-Louise Hammarskjold
- Myles H. Thaler Center for AIDS and Human Retrovirus Research, University of Virginia, Charlottesville, Virginia, USA.,Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - William Ritchie
- IGH, Centre National de la Recherche Scientifique, University of Montpellier, Montpellier, France
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