101
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Tellier M, Maudlin I, Murphy S. Transcription and splicing: A two-way street. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1593. [PMID: 32128990 DOI: 10.1002/wrna.1593] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/18/2019] [Accepted: 02/12/2020] [Indexed: 12/11/2022]
Abstract
RNA synthesis by RNA polymerase II and RNA processing are closely coupled during the transcription cycle of protein-coding genes. This coupling affords opportunities for quality control and regulation of gene expression and the effects can go in both directions. For example, polymerase speed can affect splice site selection and splicing can increase transcription and affect the chromatin landscape. Here we review the many ways that transcription and splicing influence one another, including how splicing "talks back" to transcription. We will also place the connections between transcription and splicing in the context of other RNA processing events that define the exons that will make up the final mRNA. This article is categorized under: RNA Processing > Splicing Mechanisms RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
- Michael Tellier
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Isabella Maudlin
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Shona Murphy
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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102
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Zhao S, Ye Z, Stanton R. Misuse of RPKM or TPM normalization when comparing across samples and sequencing protocols. RNA (NEW YORK, N.Y.) 2020; 26:903-909. [PMID: 32284352 PMCID: PMC7373998 DOI: 10.1261/rna.074922.120] [Citation(s) in RCA: 245] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
In recent years, RNA-sequencing (RNA-seq) has emerged as a powerful technology for transcriptome profiling. For a given gene, the number of mapped reads is not only dependent on its expression level and gene length, but also the sequencing depth. To normalize these dependencies, RPKM (reads per kilobase of transcript per million reads mapped) and TPM (transcripts per million) are used to measure gene or transcript expression levels. A common misconception is that RPKM and TPM values are already normalized, and thus should be comparable across samples or RNA-seq projects. However, RPKM and TPM represent the relative abundance of a transcript among a population of sequenced transcripts, and therefore depend on the composition of the RNA population in a sample. Quite often, it is reasonable to assume that total RNA concentration and distributions are very close across compared samples. Nevertheless, the sequenced RNA repertoires may differ significantly under different experimental conditions and/or across sequencing protocols; thus, the proportion of gene expression is not directly comparable in such cases. In this review, we illustrate typical scenarios in which RPKM and TPM are misused, unintentionally, and hope to raise scientists' awareness of this issue when comparing them across samples or different sequencing protocols.
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Affiliation(s)
- Shanrong Zhao
- Integrative Biology Center of Excellence, Pfizer Worldwide Research and Development, Cambridge, Massachusetts 02139, USA
| | - Zhan Ye
- Early Clinical Development, Pfizer Worldwide Research and Development, Cambridge, Massachusetts 02139, USA
| | - Robert Stanton
- Integrative Biology Center of Excellence, Pfizer Worldwide Research and Development, Cambridge, Massachusetts 02139, USA
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103
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Lee D, Zhang J, Liu J, Gerstein M. Epigenome-based splicing prediction using a recurrent neural network. PLoS Comput Biol 2020; 16:e1008006. [PMID: 32584815 PMCID: PMC7343189 DOI: 10.1371/journal.pcbi.1008006] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/08/2020] [Accepted: 06/01/2020] [Indexed: 12/16/2022] Open
Abstract
Alternative RNA splicing provides an important means to expand metazoan transcriptome diversity. Contrary to what was accepted previously, splicing is now thought to predominantly take place during transcription. Motivated by emerging data showing the physical proximity of the spliceosome to Pol II, we surveyed the effect of epigenetic context on co-transcriptional splicing. In particular, we observed that splicing factors were not necessarily enriched at exon junctions and that most epigenetic signatures had a distinctly asymmetric profile around known splice sites. Given this, we tried to build an interpretable model that mimics the physical layout of splicing regulation where the chromatin context progressively changes as the Pol II moves along the guide DNA. We used a recurrent-neural-network architecture to predict the inclusion of a spliced exon based on adjacent epigenetic signals, and we showed that distinct spatio-temporal features of these signals were key determinants of model outcome, in addition to the actual nucleotide sequence of the guide DNA strand. After the model had been trained and tested (with >80% precision-recall curve metric), we explored the derived weights of the latent factors, finding they highlight the importance of the asymmetric time-direction of chromatin context during transcription.
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Affiliation(s)
- Donghoon Lee
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Jing Zhang
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Jason Liu
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Mark Gerstein
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Computer Science, Yale University, New Haven, Connecticut, United States of America
- Department of Statistics and Data Science, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
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104
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Ding J, Adiconis X, Simmons SK, Kowalczyk MS, Hession CC, Marjanovic ND, Hughes TK, Wadsworth MH, Burks T, Nguyen LT, Kwon JYH, Barak B, Ge W, Kedaigle AJ, Carroll S, Li S, Hacohen N, Rozenblatt-Rosen O, Shalek AK, Villani AC, Regev A, Levin JZ. Systematic comparison of single-cell and single-nucleus RNA-sequencing methods. Nat Biotechnol 2020; 38:737-746. [PMID: 32341560 PMCID: PMC7289686 DOI: 10.1038/s41587-020-0465-8] [Citation(s) in RCA: 537] [Impact Index Per Article: 107.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 02/24/2020] [Indexed: 01/06/2023]
Abstract
The scale and capabilities of single-cell RNA-sequencing methods have expanded rapidly in recent years, enabling major discoveries and large-scale cell mapping efforts. However, these methods have not been systematically and comprehensively benchmarked. Here, we directly compare seven methods for single-cell and/or single-nucleus profiling-selecting representative methods based on their usage and our expertise and resources to prepare libraries-including two low-throughput and five high-throughput methods. We tested the methods on three types of samples: cell lines, peripheral blood mononuclear cells and brain tissue, generating 36 libraries in six separate experiments in a single center. To directly compare the methods and avoid processing differences introduced by the existing pipelines, we developed scumi, a flexible computational pipeline that can be used with any single-cell RNA-sequencing method. We evaluated the methods for both basic performance, such as the structure and alignment of reads, sensitivity and extent of multiplets, and for their ability to recover known biological information in the samples.
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Affiliation(s)
- Jiarui Ding
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Xian Adiconis
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | | | | | | | - Travis K Hughes
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Institute for Medical Engineering and Science, Department of Chemistry, MIT, Cambridge, MA, USA
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
- Koch Institute of Integrative Cancer Research, Cambridge, MA, USA
| | - Marc H Wadsworth
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Institute for Medical Engineering and Science, Department of Chemistry, MIT, Cambridge, MA, USA
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
- Koch Institute of Integrative Cancer Research, Cambridge, MA, USA
| | - Tyler Burks
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Lan T Nguyen
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - John Y H Kwon
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Boaz Barak
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA
| | - William Ge
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | - Shaina Carroll
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Institute for Medical Engineering and Science, Department of Chemistry, MIT, Cambridge, MA, USA
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
- Koch Institute of Integrative Cancer Research, Cambridge, MA, USA
| | - Shuqiang Li
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Nir Hacohen
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Center for Cancer Research, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | | | - Alex K Shalek
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Institute for Medical Engineering and Science, Department of Chemistry, MIT, Cambridge, MA, USA
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
- Koch Institute of Integrative Cancer Research, Cambridge, MA, USA
| | - Alexandra-Chloé Villani
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Center for Cancer Research, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
- Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Charlestown, MA, USA
| | - Aviv Regev
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Koch Institute of Integrative Cancer Research, Cambridge, MA, USA
- Howard Hughes Medical Institute, Department of Biology, MIT, Cambridge, MA, USA
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105
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Abou Alezz M, Celli L, Belotti G, Lisa A, Bione S. GC-AG Introns Features in Long Non-coding and Protein-Coding Genes Suggest Their Role in Gene Expression Regulation. Front Genet 2020; 11:488. [PMID: 32499820 PMCID: PMC7242645 DOI: 10.3389/fgene.2020.00488] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 04/20/2020] [Indexed: 12/16/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) are recognized as an important class of regulatory molecules involved in a variety of biological functions. However, the regulatory mechanisms of long non-coding genes expression are still poorly understood. The characterization of the genomic features of lncRNAs is crucial to get insight into their function. In this study, we exploited recent annotations by GENCODE to characterize the genomic and splicing features of long non-coding genes in comparison with protein-coding ones, both in human and mouse. Our analysis highlighted differences between the two classes of genes in terms of their gene architecture. Significant differences in the splice sites usage were observed between long non-coding and protein-coding genes (PCG). While the frequency of non-canonical GC-AG splice junctions represents about 0.8% of total splice sites in PCGs, we identified a significant enrichment of the GC-AG splice sites in long non-coding genes, both in human (3.0%) and mouse (1.9%). In addition, we found a positional bias of GC-AG splice sites being enriched in the first intron in both classes of genes. Moreover, a significant shorter length and weaker donor and acceptor sites were found comparing GC-AG introns to GT-AG introns. Genes containing at least one GC-AG intron were found conserved in many species, more prone to alternative splicing and a functional analysis pointed toward their enrichment in specific biological processes such as DNA repair. Our study shows for the first time that GC-AG introns are mainly associated with lncRNAs and are preferentially located in the first intron. Additionally, we discovered their regulatory potential indicating the existence of a new mechanism of non-coding and PCGs expression regulation.
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Affiliation(s)
| | | | | | | | - Silvia Bione
- Computational Biology Unit, Institute of Molecular Genetics Luigi Luca Cavalli-Sforza, National Research Council, Pavia, Italy
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106
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Thillainadesan G, Xiao H, Holla S, Dhakshnamoorthy J, Jenkins LMM, Wheeler D, Grewal SIS. Conserved protein Pir2 ARS2 mediates gene repression through cryptic introns in lncRNAs. Nat Commun 2020; 11:2412. [PMID: 32415063 PMCID: PMC7229227 DOI: 10.1038/s41467-020-16280-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 04/21/2020] [Indexed: 02/07/2023] Open
Abstract
Long non-coding RNAs (lncRNAs) are components of epigenetic control mechanisms that ensure appropriate and timely gene expression. The functions of lncRNAs are often mediated through associated gene regulatory activities, but how lncRNAs are distinguished from other RNAs and recruit effector complexes is unclear. Here, we utilize the fission yeast Schizosaccharomyces pombe to investigate how lncRNAs engage silencing activities to regulate gene expression in cis. We find that invasion of lncRNA transcription into the downstream gene body incorporates a cryptic intron required for repression of that gene. Our analyses show that lncRNAs containing cryptic introns are targeted by the conserved Pir2ARS2 protein in association with splicing factors, which recruit RNA processing and chromatin-modifying activities involved in gene silencing. Pir2 and splicing machinery are broadly required for gene repression. Our finding that human ARS2 also interacts with splicing factors suggests a conserved mechanism mediates gene repression through cryptic introns within lncRNAs. In fission yeast, several lncRNAs act in cis to regulate expression of adjacent genes. Here, the authors show that the conserved Pir2ARS2 protein is targeted, along with splicing factors, to cryptic introns in lncRNAs and recruits effectors, including RNAi machinery, for gene repression.
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Affiliation(s)
- Gobi Thillainadesan
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Hua Xiao
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sahana Holla
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jothy Dhakshnamoorthy
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Lisa M Miller Jenkins
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - David Wheeler
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Shiv I S Grewal
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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107
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Yin Y, Lu JY, Zhang X, Shao W, Xu Y, Li P, Hong Y, Cui L, Shan G, Tian B, Zhang QC, Shen X. U1 snRNP regulates chromatin retention of noncoding RNAs. Nature 2020; 580:147-150. [PMID: 32238924 PMCID: PMC12018070 DOI: 10.1038/s41586-020-2105-3] [Citation(s) in RCA: 136] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 01/09/2020] [Indexed: 12/21/2022]
Abstract
Long noncoding RNAs (lncRNAs) and promoter- or enhancer-associated unstable transcripts locate preferentially to chromatin, where some regulate chromatin structure, transcription and RNA processing1-13. Although several RNA sequences responsible for nuclear localization have been identified-such as repeats in the lncRNA Xist and Alu-like elements in long RNAs14-16-how lncRNAs as a class are enriched at chromatin remains unknown. Here we describe a random, mutagenesis-coupled, high-throughput method that we name 'RNA elements for subcellular localization by sequencing' (mutREL-seq). Using this method, we discovered an RNA motif that recognizes the U1 small nuclear ribonucleoprotein (snRNP) and is essential for the localization of reporter RNAs to chromatin. Across the genome, chromatin-bound lncRNAs are enriched with 5' splice sites and depleted of 3' splice sites, and exhibit high levels of U1 snRNA binding compared with cytoplasm-localized messenger RNAs. Acute depletion of U1 snRNA or of the U1 snRNP protein component SNRNP70 markedly reduces the chromatin association of hundreds of lncRNAs and unstable transcripts, without altering the overall transcription rate in cells. In addition, rapid degradation of SNRNP70 reduces the localization of both nascent and polyadenylated lncRNA transcripts to chromatin, and disrupts the nuclear and genome-wide localization of the lncRNA Malat1. Moreover, U1 snRNP interacts with transcriptionally engaged RNA polymerase II. These results show that U1 snRNP acts widely to tether and mobilize lncRNAs to chromatin in a transcription-dependent manner. Our findings have uncovered a previously unknown role of U1 snRNP beyond the processing of precursor mRNA, and provide molecular insight into how lncRNAs are recruited to regulatory sites to carry out chromatin-associated functions.
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Affiliation(s)
- Yafei Yin
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China.
| | - J Yuyang Lu
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China
| | - Xuechun Zhang
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China
| | - Wen Shao
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China
| | - Yanhui Xu
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China
| | - Pan Li
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing, China
| | - Yantao Hong
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China
| | - Li Cui
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China
| | - Ge Shan
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui Province, China
| | - Bin Tian
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School and Rutgers Cancer Institute of New Jersey, Newark, NJ, USA
| | - Qiangfeng Cliff Zhang
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing, China
| | - Xiaohua Shen
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China.
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108
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Botto AEC, Muñoz JC, Giono LE, Nieto-Moreno N, Cuenca C, Kornblihtt AR, Muñoz MJ. Reciprocal regulation between alternative splicing and the DNA damage response. Genet Mol Biol 2020; 43:e20190111. [PMID: 32236390 PMCID: PMC7197977 DOI: 10.1590/1678-4685-gmb-2019-0111] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 12/16/2019] [Indexed: 12/16/2022] Open
Abstract
Splicing, the process that catalyzes intron removal and flanking exon ligation, can occur in different ways (alternative splicing) in immature RNAs transcribed from a single gene. In order to adapt to a particular context, cells modulate not only the quantity but also the quality (alternative isoforms) of their transcriptome. Since 95% of the human coding genome is subjected to alternative splicing regulation, it is expected that many cellular pathways are modulated by alternative splicing, as is the case for the DNA damage response. Moreover, recent evidence demonstrates that upon a genotoxic insult, classical DNA damage response kinases such as ATM, ATR and DNA-PK orchestrate the gene expression response therefore modulating alternative splicing which, in a reciprocal way, shapes the response to a damaging agent.
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Affiliation(s)
- Adrian E Cambindo Botto
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina
| | - Juan C Muñoz
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina
| | - Luciana E Giono
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina
| | - Nicolás Nieto-Moreno
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina
| | - Carmen Cuenca
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina
| | - Alberto R Kornblihtt
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina
| | - Manuel J Muñoz
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiologia, Biologia Molecular y Celular, Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE-UBA-CONICET), Buenos Aires, Argentina.,Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Milan, Italy.,Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
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109
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Drexler HL, Choquet K, Churchman LS. Splicing Kinetics and Coordination Revealed by Direct Nascent RNA Sequencing through Nanopores. Mol Cell 2020; 77:985-998.e8. [PMID: 31839405 PMCID: PMC7060811 DOI: 10.1016/j.molcel.2019.11.017] [Citation(s) in RCA: 140] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/17/2019] [Accepted: 11/18/2019] [Indexed: 02/06/2023]
Abstract
Understanding how splicing events are coordinated across numerous introns in metazoan RNA transcripts requires quantitative analyses of transient RNA processing events in living cells. We developed nanopore analysis of co-transcriptional processing (nano-COP), in which nascent RNAs are directly sequenced through nanopores, exposing the dynamics and patterns of RNA splicing without biases introduced by amplification. Long nano-COP reads reveal that, in human and Drosophila cells, splicing occurs after RNA polymerase II transcribes several kilobases of pre-mRNA, suggesting that metazoan splicing transpires distally from the transcription machinery. Inhibition of the branch-site recognition complex SF3B rapidly diminished global co-transcriptional splicing. We found that splicing order does not strictly follow the order of transcription and is associated with cis-acting elements, alternative splicing, and RNA-binding factors. Further, neighboring introns in human cells tend to be spliced concurrently, implying that splicing of these introns occurs cooperatively. Thus, nano-COP unveils the organizational complexity of RNA processing.
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Affiliation(s)
- Heather L Drexler
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Karine Choquet
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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110
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Tan JY, Biasini A, Young RS, Marques AC. Splicing of enhancer-associated lincRNAs contributes to enhancer activity. Life Sci Alliance 2020; 3:3/4/e202000663. [PMID: 32086317 PMCID: PMC7035876 DOI: 10.26508/lsa.202000663] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 12/19/2022] Open
Abstract
Transcription is common at active mammalian enhancers sometimes giving rise to stable enhancer-associated long intergenic noncoding RNAs (elincRNAs). Expression of elincRNA is associated with changes in neighboring gene product abundance and local chromosomal topology, suggesting that transcription at these loci contributes to gene expression regulation in cis Despite the lack of evidence supporting sequence-dependent functions for most elincRNAs, splicing of these transcripts is unexpectedly common. Whether elincRNA splicing is a mere consequence of cognate enhancer activity or if it directly impacts enhancer function remains unresolved. Here, we investigate the association between elincRNA splicing and enhancer activity in mouse embryonic stem cells. We show that multi-exonic elincRNAs are enriched at conserved enhancers, and the efficient processing of elincRNAs is strongly associated with their cognate enhancer activity. This association is supported by their enrichment in enhancer-specific chromatin signatures; elevated binding of co-transcriptional regulators; increased local intra-chromosomal DNA contacts; and strengthened cis-regulation on target gene expression. Our results support the role of efficient RNA processing of enhancer-associated transcripts to cognate enhancer activity.
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Affiliation(s)
- Jennifer Y Tan
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
| | - Adriano Biasini
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
| | - Robert S Young
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics & Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Ana C Marques
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
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111
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Sun X, Wang Z, Hall JM, Perez-Cervantes C, Ruthenburg AJ, Moskowitz IP, Gribskov M, Yang XH. Chromatin-enriched RNAs mark active and repressive cis-regulation: An analysis of nuclear RNA-seq. PLoS Comput Biol 2020; 16:e1007119. [PMID: 32040509 PMCID: PMC7034927 DOI: 10.1371/journal.pcbi.1007119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 02/21/2020] [Accepted: 01/14/2020] [Indexed: 01/22/2023] Open
Abstract
Long noncoding RNAs (lncRNAs) localize in the cell nucleus and influence gene expression through a variety of molecular mechanisms. Chromatin-enriched RNAs (cheRNAs) are a unique class of lncRNAs that are tightly bound to chromatin and putatively function to locally cis-activate gene transcription. CheRNAs can be identified by biochemical fractionation of nuclear RNA followed by RNA sequencing, but until now, a rigorous analytic pipeline for nuclear RNA-seq has been lacking. In this study, we survey four computational strategies for nuclear RNA-seq data analysis and develop a new pipeline, Tuxedo-ch, which outperforms other approaches. Tuxedo-ch assembles a more complete transcriptome and identifies cheRNA with higher accuracy than other approaches. We used Tuxedo-ch to analyze benchmark datasets of K562 cells and further characterize the genomic features of intergenic cheRNA (icheRNA) and their similarity to enhancer RNAs (eRNAs). We quantify the transcriptional correlation of icheRNA and adjacent genes and show that icheRNA is more positively associated with neighboring gene expression than eRNA or cap analysis of gene expression (CAGE) signals. We also explore two novel genomic associations of cheRNA, which indicate that cheRNAs may function to promote or repress gene expression in a context-dependent manner. IcheRNA loci with significant levels of H3K9me3 modifications are associated with active enhancers, consistent with the hypothesis that enhancers are derived from ancient mobile elements. In contrast, antisense cheRNA (as-cheRNA) may play a role in local gene repression, possibly through local RNA:DNA:DNA triple-helix formation. Nuclear RNA-seq provides a powerful way to profile the transcriptional landscape, especially the noncoding transcriptome. Through analyzing nuclear RNA-seq, the chromatin-enriched RNA (cheRNA) class of gene regulatory non-coding RNAs was identified. The computational framework presented here provides a reliable approach to identifying cheRNAs from nuclear RNA-seq, and for studying cell-type specific gene regulation. We find that intergenic cheRNA, including transcripts mapped to regions with high levels of classically repressive H3K9me3-marks, may act as a transcriptional activator. In contrast, antisense cheRNA, which originates from the DNA strand complementary to the candidate target protein-coding gene may interact with diverse chromatin modulators to repress local transcription. Our new pipeline allows the identification of a more complete set of cheRNAs than other approaches. A future challenge will be to refine the functional mechanisms of cheRNAs by exploring their regulatory roles, which are involved in diverse molecular and cellular processes in humans and other organisms.
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Affiliation(s)
- Xiangying Sun
- Department of Pediatrics, The University of Chicago, Chicago, Illinois, United States of America
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Zhezhen Wang
- Department of Pediatrics, The University of Chicago, Chicago, Illinois, United States of America
| | - Johnathon M Hall
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Carlos Perez-Cervantes
- Department of Pediatrics, The University of Chicago, Chicago, Illinois, United States of America
| | - Alexander J Ruthenburg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Ivan P Moskowitz
- Department of Pediatrics, The University of Chicago, Chicago, Illinois, United States of America
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Michael Gribskov
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
- Department of Computer Science, Purdue University, West Lafayette, Indiana, United States of America
| | - Xinan H Yang
- Department of Pediatrics, The University of Chicago, Chicago, Illinois, United States of America
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112
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Li S, Wang Y, Zhao Y, Zhao X, Chen X, Gong Z. Global Co-transcriptional Splicing in Arabidopsis and the Correlation with Splicing Regulation in Mature RNAs. MOLECULAR PLANT 2020; 13:266-277. [PMID: 31759129 PMCID: PMC8034514 DOI: 10.1016/j.molp.2019.11.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 11/01/2019] [Accepted: 11/07/2019] [Indexed: 05/20/2023]
Abstract
RNA splicing and spliceosome assembly in eukaryotes occur mainly during transcription. However, co-transcriptional splicing has not yet been explored in plants. Here, we built transcriptomes of nascent chromatin RNAs in Arabidopsis thaliana and showed that nearly all introns undergo co-transcriptional splicing, which occurs with higher efficiency for introns in protein-coding genes than for those in noncoding RNAs. Total intron number and intron position are two predominant features that correlate with co-transcriptional splicing efficiency, and introns with alternative 5' or 3' splice sites are less efficiently spliced. Furthermore, we found that mutations in genes encoding trans-acting proteins lead to more introns with increased splicing defects in nascent RNAs than in mature RNAs, and that introns with increased splicing defects in mature RNAs are inefficiently spliced at the co-transcriptional level. Collectively, our results not only uncovered widespread co-transcriptional splicing in Arabidopsis but also identified features that may affect or be affected by co-transcriptional splicing efficiency.
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Affiliation(s)
- Shaofang Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Joint Laboratory for International Cooperation in Crop Molecular Breeding, China Agricultural University, Beijing 100193, China.
| | - Yuan Wang
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA; Guangdong Provincial Key Laboratory for Plant Epigenetics, Longhua Institute of Innovative Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Yonghui Zhao
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA; Plant Phenomics Research Center, Nanjing Agricultural University, Nanjing 210018, China
| | - Xinjie Zhao
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Joint Laboratory for International Cooperation in Crop Molecular Breeding, China Agricultural University, Beijing 100193, China
| | - Xuemei Chen
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Zhizhong Gong
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Joint Laboratory for International Cooperation in Crop Molecular Breeding, China Agricultural University, Beijing 100193, China
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113
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Zhu D, Mao F, Tian Y, Lin X, Gu L, Gu H, Qu LJ, Wu Y, Wu Z. The Features and Regulation of Co-transcriptional Splicing in Arabidopsis. MOLECULAR PLANT 2020; 13:278-294. [PMID: 31760161 DOI: 10.1016/j.molp.2019.11.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 09/29/2019] [Accepted: 11/15/2019] [Indexed: 05/20/2023]
Abstract
Precursor mRNA (pre-mRNA) splicing is essential for gene expression in most eukaryotic organisms. Previous studies from mammals, Drosophila, and yeast show that the majority of splicing events occurs co-transcriptionally. In plants, however, the features of co-transcriptional splicing (CTS) and its regulation still remain largely unknown. Here, we used chromatin-bound RNA sequencing to study CTS in Arabidopsis thaliana. We found that CTS is widespread in Arabidopsis seedlings, with a large proportion of alternative splicing events determined co-transcriptionally. CTS efficiency correlated with gene expression level, the chromatin landscape and, most surprisingly, the number of introns and exons of individual genes, but is independent of gene length. In combination with enhanced crosslinking and immunoprecipitation sequencing analysis, we further showed that the hnRNP-like proteins RZ-1B and RZ-1C promote efficient CTS globally through direct binding, frequently to exonic sequences. Notably, this general effect of RZ-1B/1C on splicing promotion is mainly observed at the chromatin level, not at the mRNA level. RZ-1C promotes CTS of multiple-exon genes in association with its binding to regions both proximal and distal to the regulated introns. We propose that RZ-1C promotes efficient CTS of genes with multiple exons through cooperative interactions with many exons, introns, and splicing factors. Our work thus reveals important features of CTS in plants and provides methodologies for the investigation of CTS and RNA-binding proteins in plants.
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Affiliation(s)
- Danling Zhu
- SUSTech-PKU Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
| | - Fei Mao
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Bioinformatics Center, Nanjing Agriculture University, Nanjing, Jiangsu 210095, China
| | - Yuanchun Tian
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Bioinformatics Center, Nanjing Agriculture University, Nanjing, Jiangsu 210095, China
| | - Xiaoya Lin
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing 100871, China
| | - Lianfeng Gu
- Basic Forestry and Proteomics Research Center, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Hongya Gu
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing 100871, China
| | - Li-Jia Qu
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing 100871, China
| | - Yufeng Wu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Bioinformatics Center, Nanjing Agriculture University, Nanjing, Jiangsu 210095, China.
| | - Zhe Wu
- SUSTech-PKU Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China.
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114
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Pendergraff H, Schmidt S, Vikeså J, Weile C, Øverup C, W. Lindholm M, Koch T. Nuclear and Cytoplasmatic Quantification of Unconjugated, Label-Free Locked Nucleic Acid Oligonucleotides. Nucleic Acid Ther 2020; 30:4-13. [PMID: 31618108 PMCID: PMC6987631 DOI: 10.1089/nat.2019.0810] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 08/28/2019] [Indexed: 12/23/2022] Open
Abstract
Methods for the quantification of antisense oligonucleotides (AONs) provide insightful information on biodistribution and intracellular trafficking. However, the established methods have not provided information on the absolute number of molecules in subcellular compartments or about how many AONs are needed for target gene reduction for unconjugated AONs. We have developed a new method for nuclear AON quantification that enables us to determine the absolute number of AONs per nucleus without relying on AON conjugates such as fluorophores that may alter AON distribution. This study describes an alternative and label-free method using subcellular fractionation, nucleus counting, and locked nucleic acid (LNA) sandwich enzyme-linked immunosorbent assay to quantify absolute numbers of oligonucleotides in nuclei. Our findings show compound variability (diversity) by which 247,000-693,000 LNAs/nuclei results in similar target reduction for different compounds. This method can be applied to any antisense drug discovery platform providing information on specific and clinically relevant AONs. Finally, this method can directly compare nuclear entry of AON with target gene knockdown for any compound design and nucleobase sequence, gene target, and phosphorothioate stereochemistry.
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Affiliation(s)
- Hannah Pendergraff
- Roche Pharma Research and Early Development, RNA Therapeutics Research, Roche Innovation Center Copenhagen, Hørsholm, Denmark
| | - Steffen Schmidt
- Roche Pharma Research and Early Development, RNA Therapeutics Research, Roche Innovation Center Copenhagen, Hørsholm, Denmark
| | - Jonas Vikeså
- Roche Pharma Research and Early Development, RNA Therapeutics Research, Roche Innovation Center Copenhagen, Hørsholm, Denmark
| | - Christian Weile
- Roche Pharma Research and Early Development, RNA Therapeutics Research, Roche Innovation Center Copenhagen, Hørsholm, Denmark
| | - Charlotte Øverup
- Roche Pharma Research and Early Development, RNA Therapeutics Research, Roche Innovation Center Copenhagen, Hørsholm, Denmark
| | - Marie W. Lindholm
- Roche Pharma Research and Early Development, RNA Therapeutics Research, Roche Innovation Center Copenhagen, Hørsholm, Denmark
| | - Troels Koch
- Roche Pharma Research and Early Development, RNA Therapeutics Research, Roche Innovation Center Copenhagen, Hørsholm, Denmark
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115
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Auboeuf D. Physicochemical Foundations of Life that Direct Evolution: Chance and Natural Selection are not Evolutionary Driving Forces. Life (Basel) 2020; 10:life10020007. [PMID: 31973071 PMCID: PMC7175370 DOI: 10.3390/life10020007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/15/2020] [Accepted: 01/16/2020] [Indexed: 12/11/2022] Open
Abstract
The current framework of evolutionary theory postulates that evolution relies on random mutations generating a diversity of phenotypes on which natural selection acts. This framework was established using a top-down approach as it originated from Darwinism, which is based on observations made of complex multicellular organisms and, then, modified to fit a DNA-centric view. In this article, it is argued that based on a bottom-up approach starting from the physicochemical properties of nucleic and amino acid polymers, we should reject the facts that (i) natural selection plays a dominant role in evolution and (ii) the probability of mutations is independent of the generated phenotype. It is shown that the adaptation of a phenotype to an environment does not correspond to organism fitness, but rather corresponds to maintaining the genome stability and integrity. In a stable environment, the phenotype maintains the stability of its originating genome and both (genome and phenotype) are reproduced identically. In an unstable environment (i.e., corresponding to variations in physicochemical parameters above a physiological range), the phenotype no longer maintains the stability of its originating genome, but instead influences its variations. Indeed, environment- and cellular-dependent physicochemical parameters define the probability of mutations in terms of frequency, nature, and location in a genome. Evolution is non-deterministic because it relies on probabilistic physicochemical rules, and evolution is driven by a bidirectional interplay between genome and phenotype in which the phenotype ensures the stability of its originating genome in a cellular and environmental physicochemical parameter-depending manner.
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Affiliation(s)
- Didier Auboeuf
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie, Site Jacques Monod, F-69007, Lyon, France
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116
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Price AJ, Hwang T, Tao R, Burke EE, Rajpurohit A, Shin JH, Hyde TM, Kleinman JE, Jaffe AE, Weinberger DR. Characterizing the nuclear and cytoplasmic transcriptomes in developing and mature human cortex uncovers new insight into psychiatric disease gene regulation. Genome Res 2020; 30:1-11. [PMID: 31852722 PMCID: PMC6961577 DOI: 10.1101/gr.250217.119] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 12/16/2019] [Indexed: 12/24/2022]
Abstract
Transcriptome compartmentalization by the nuclear membrane provides both stochastic and functional buffering of transcript activity in the cytoplasm, and has recently been implicated in neurodegenerative disease processes. Although many mechanisms regulating transcript compartmentalization are also prevalent in brain development, the extent to which subcellular localization differs as the brain matures has yet to be addressed. To characterize the nuclear and cytoplasmic transcriptomes during brain development, we sequenced both RNA fractions from homogenate prenatal and adult human postmortem cortex using poly(A)+ and Ribo-Zero library preparation methods. We find that while many genes are differentially expressed by fraction and developmental expression changes are similarly detectable in nuclear and cytoplasmic RNA, the compartmented transcriptomes become more distinct as the brain matures, perhaps reflecting increased utilization of nuclear retention as a regulatory strategy in adult brain. We examined potential mechanisms of this developmental divergence including alternative splicing, RNA editing, nuclear pore composition, RNA-binding protein motif enrichment, and RNA secondary structure. Intron retention is associated with greater nuclear abundance in a subset of transcripts, as is enrichment for several splicing factor binding motifs. Finally, we examined disease association with fraction-regulated gene sets and found nuclear-enriched genes were also preferentially enriched in gene sets associated with neurodevelopmental psychiatric disorders. These results suggest that although gene-level expression is globally comparable between fractions, nuclear retention of transcripts may play an underappreciated role in developmental regulation of gene expression in brain, particularly in genes whose dysregulation is related to neuropsychiatric disorders.
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Affiliation(s)
- Amanda J Price
- Lieber Institute for Brain Development, Baltimore, Maryland 21205, USA
- McKusick Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
| | - Taeyoung Hwang
- Lieber Institute for Brain Development, Baltimore, Maryland 21205, USA
| | - Ran Tao
- Lieber Institute for Brain Development, Baltimore, Maryland 21205, USA
| | - Emily E Burke
- Lieber Institute for Brain Development, Baltimore, Maryland 21205, USA
| | | | - Joo Heon Shin
- Lieber Institute for Brain Development, Baltimore, Maryland 21205, USA
| | - Thomas M Hyde
- Lieber Institute for Brain Development, Baltimore, Maryland 21205, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
| | - Joel E Kleinman
- Lieber Institute for Brain Development, Baltimore, Maryland 21205, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
| | - Andrew E Jaffe
- Lieber Institute for Brain Development, Baltimore, Maryland 21205, USA
- McKusick Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
- Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
| | - Daniel R Weinberger
- Lieber Institute for Brain Development, Baltimore, Maryland 21205, USA
- McKusick Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
- Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
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117
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Yin Y, Shen X. Identification of cis-Elements for RNA Subcellular Localization Through REL-seq. Methods Mol Biol 2020; 2161:143-160. [PMID: 32681511 DOI: 10.1007/978-1-0716-0680-3_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The subcellular localization of RNAs is regulated by cis-regulatory elements together with interacting trans factors. Here we describe a high-throughput sequencing-based method named REL-seq (RNA elements for subcellular localization by sequencing) to identify the cis-elements that contribute to RNA subcellular localization. By coupling REL-seq with random mutagenesis (mutREL-seq), we can further narrow down the cis-elements to key motifs at single-nucleotide resolution.
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Affiliation(s)
- Yafei Yin
- Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, China
| | - Xiaohua Shen
- Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, China.
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118
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Wang J, Chen S, Jiang N, Li N, Wang X, Li Z, Li X, Liu H, Li L, Yang Y, Ni T, Yu C, Ma J, Zheng B, Ren G. Spliceosome disassembly factors ILP1 and NTR1 promote miRNA biogenesis in Arabidopsis thaliana. Nucleic Acids Res 2019; 47:7886-7900. [PMID: 31216029 PMCID: PMC6736097 DOI: 10.1093/nar/gkz526] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 05/13/2019] [Accepted: 06/03/2019] [Indexed: 12/23/2022] Open
Abstract
The intron-lariat spliceosome (ILS) complex is highly conserved among eukaryotes, and its disassembly marks the end of a canonical splicing cycle. In this study, we show that two conserved disassembly factors of the ILS complex, Increased Level of Polyploidy1-1D (ILP1) and NTC-Related protein 1 (NTR1), positively regulate microRNA (miRNA) biogenesis by facilitating transcriptional elongation of MIRNA (MIR) genes in Arabidopsis thaliana. ILP1 and NTR1 formed a stable complex and co-regulated alternative splicing of more than a hundred genes across the Arabidopsis genome, including some primary transcripts of miRNAs (pri-miRNAs). Intriguingly, pri-miRNAs, regardless of having introns or not, were globally down-regulated when the ILP1 or NTR1 function was compromised. ILP1 and NTR1 interacted with core miRNA processing proteins Dicer-like 1 and Serrate, and were required for proper RNA polymerase II occupancy at elongated regions of MIR chromatin, without affecting either MIR promoter activity or pri-miRNA decay. Our results provide further insights into the regulatory role of spliceosomal machineries in the biogenesis of miRNAs.
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Affiliation(s)
- Junli Wang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Susu Chen
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Ning Jiang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Ning Li
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Xiaoyan Wang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Zhongpeng Li
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Xu Li
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences, Shanghai 200032, P.R. China
| | - Hongtao Liu
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences, Shanghai 200032, P.R. China
| | - Lin Li
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Yu Yang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Ting Ni
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Chaoyi Yu
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Jinbiao Ma
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Binglian Zheng
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Guodong Ren
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
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119
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Mora Gallardo C, Sánchez de Diego A, Gutiérrez Hernández J, Talavera-Gutiérrez A, Fischer T, Martínez-A C, van Wely KHM. Dido3-dependent SFPQ recruitment maintains efficiency in mammalian alternative splicing. Nucleic Acids Res 2019; 47:5381-5394. [PMID: 30931476 PMCID: PMC6547428 DOI: 10.1093/nar/gkz235] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 03/19/2019] [Accepted: 03/22/2019] [Indexed: 12/12/2022] Open
Abstract
Alternative splicing is facilitated by accessory proteins that guide spliceosome subunits to the primary transcript. Many of these splicing factors recognize the RNA polymerase II tail, but SFPQ is a notable exception even though essential for mammalian RNA processing. This study reveals a novel role for Dido3, one of three Dido gene products, in alternative splicing. Binding of the Dido3 amino terminus to histones and to the polymerase jaw domain was previously reported, and here we show interaction between its carboxy terminus and SFPQ. We generated a mutant that eliminates Dido3 but preserves other Dido gene products, mimicking reduced Dido3 levels in myeloid neoplasms. Dido mutation suppressed SFPQ binding to RNA and increased skipping for a large group of exons. Exons bearing recognition sequences for alternative splicing factors were nonetheless included more efficiently. Reduced SFPQ recruitment may thus account for increased skipping of SFPQ-dependent exons, but could also generate a splicing factor surplus that becomes available to competing splice sites. Taken together, our data indicate that Dido3 is an adaptor that controls SFPQ utilization in RNA splicing. Distributing splicing factor recruitment over parallel pathways provides mammals with a simple mechanism to regulate exon usage while maintaining RNA splicing efficiency.
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Affiliation(s)
- Carmen Mora Gallardo
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Campus UAM Cantoblanco, 28049 Madrid, Spain
| | - Ainhoa Sánchez de Diego
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Campus UAM Cantoblanco, 28049 Madrid, Spain
| | - Julio Gutiérrez Hernández
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Campus UAM Cantoblanco, 28049 Madrid, Spain
| | - Amaia Talavera-Gutiérrez
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Campus UAM Cantoblanco, 28049 Madrid, Spain
| | - Thierry Fischer
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Campus UAM Cantoblanco, 28049 Madrid, Spain
| | - Carlos Martínez-A
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Campus UAM Cantoblanco, 28049 Madrid, Spain
| | - Karel H M van Wely
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Campus UAM Cantoblanco, 28049 Madrid, Spain
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120
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Lemaire S, Fontrodona N, Aubé F, Claude JB, Polvèche H, Modolo L, Bourgeois CF, Mortreux F, Auboeuf D. Characterizing the interplay between gene nucleotide composition bias and splicing. Genome Biol 2019; 20:259. [PMID: 31783898 PMCID: PMC6883713 DOI: 10.1186/s13059-019-1869-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 10/28/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Nucleotide composition bias plays an important role in the 1D and 3D organization of the human genome. Here, we investigate the potential interplay between nucleotide composition bias and the regulation of exon recognition during splicing. RESULTS By analyzing dozens of RNA-seq datasets, we identify two groups of splicing factors that activate either about 3200 GC-rich exons or about 4000 AT-rich exons. We show that splicing factor-dependent GC-rich exons have predicted RNA secondary structures at 5' ss and are dependent on U1 snRNP-associated proteins. In contrast, splicing factor-dependent AT-rich exons have a large number of decoy branch points, SF1- or U2AF2-binding sites and are dependent on U2 snRNP-associated proteins. Nucleotide composition bias also influences local chromatin organization, with consequences for exon recognition during splicing. Interestingly, the GC content of exons correlates with that of their hosting genes, isochores, and topologically associated domains. CONCLUSIONS We propose that regional nucleotide composition bias over several dozens of kilobase pairs leaves a local footprint at the exon level and induces constraints during splicing that can be alleviated by local chromatin organization at the DNA level and recruitment of specific splicing factors at the RNA level. Therefore, nucleotide composition bias establishes a direct link between genome organization and local regulatory processes, like alternative splicing.
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Affiliation(s)
- Sébastien Lemaire
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | - Nicolas Fontrodona
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | - Fabien Aubé
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | - Jean-Baptiste Claude
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | | | - Laurent Modolo
- LBMC Biocomputing Center, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | - Cyril F Bourgeois
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | - Franck Mortreux
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | - Didier Auboeuf
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France.
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121
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Gil N, Ulitsky I. Regulation of gene expression by cis-acting long non-coding RNAs. Nat Rev Genet 2019; 21:102-117. [DOI: 10.1038/s41576-019-0184-5] [Citation(s) in RCA: 467] [Impact Index Per Article: 77.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2019] [Indexed: 12/14/2022]
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122
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Jabre I, Reddy ASN, Kalyna M, Chaudhary S, Khokhar W, Byrne LJ, Wilson CM, Syed NH. Does co-transcriptional regulation of alternative splicing mediate plant stress responses? Nucleic Acids Res 2019; 47:2716-2726. [PMID: 30793202 PMCID: PMC6451118 DOI: 10.1093/nar/gkz121] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/11/2019] [Accepted: 02/13/2019] [Indexed: 12/15/2022] Open
Abstract
Plants display exquisite control over gene expression to elicit appropriate responses under normal and stress conditions. Alternative splicing (AS) of pre-mRNAs, a process that generates two or more transcripts from multi-exon genes, adds another layer of regulation to fine-tune condition-specific gene expression in animals and plants. However, exactly how plants control splice isoform ratios and the timing of this regulation in response to environmental signals remains elusive. In mammals, recent evidence indicate that epigenetic and epitranscriptome changes, such as DNA methylation, chromatin modifications and RNA methylation, regulate RNA polymerase II processivity, co-transcriptional splicing, and stability and translation efficiency of splice isoforms. In plants, the role of epigenetic modifications in regulating transcription rate and mRNA abundance under stress is beginning to emerge. However, the mechanisms by which epigenetic and epitranscriptomic modifications regulate AS and translation efficiency require further research. Dynamic changes in the chromatin landscape in response to stress may provide a scaffold around which gene expression, AS and translation are orchestrated. Finally, we discuss CRISPR/Cas-based strategies for engineering chromatin architecture to manipulate AS patterns (or splice isoforms levels) to obtain insight into the epigenetic regulation of AS.
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Affiliation(s)
- Ibtissam Jabre
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, UK
| | - Anireddy S N Reddy
- Department of Biology and Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1878, USA
| | - Maria Kalyna
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences - BOKU, Muthgasse 18, 1190 Vienna, Austria
| | - Saurabh Chaudhary
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, UK
| | - Waqas Khokhar
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, UK
| | - Lee J Byrne
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, UK
| | - Cornelia M Wilson
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, UK
| | - Naeem H Syed
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, UK
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123
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Xu B, Shi Y, Wu Y, Meng Y, Jin Y. Role of RNA secondary structures in regulating Dscam alternative splicing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194381. [DOI: 10.1016/j.bbagrm.2019.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/21/2019] [Accepted: 04/22/2019] [Indexed: 12/19/2022]
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124
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Maudlin IE, Beggs JD. Spt5 modulates cotranscriptional spliceosome assembly in Saccharomyces cerevisiae. RNA (NEW YORK, N.Y.) 2019; 25:1298-1310. [PMID: 31289129 PMCID: PMC6800482 DOI: 10.1261/rna.070425.119] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 05/29/2019] [Indexed: 06/09/2023]
Abstract
There is increasing evidence from yeast to humans that pre-mRNA splicing occurs mainly cotranscriptionally, such that splicing and transcription are functionally coupled. Currently, there is little insight into the contribution of the core transcription elongation machinery to cotranscriptional spliceosome assembly and pre-mRNA splicing. Spt5 is a member of the core transcription elongation machinery and an essential protein, whose absence in budding yeast causes defects in pre-mRNA splicing. To determine how Spt5 affects pre-mRNA splicing, we used the auxin-inducible degron system to conditionally deplete Spt5 in Saccharomyces cerevisiae and assayed effects on cotranscriptional spliceosome assembly and splicing. We show that Spt5 is needed for efficient splicing and for the accumulation of U5 snRNPs at intron-containing genes, and therefore for stable cotranscriptional assembly of spliceosomes. The defect in cotranscriptional spliceosome assembly can explain the relatively mild splicing defect as being a consequence of the failure of cotranscriptional splicing. Coimmunoprecipitation of Spt5 with core spliceosomal proteins and all spliceosomal snRNAs suggests a model whereby Spt5 promotes cotranscriptional pre-mRNA splicing by stabilizing the association of U5 snRNP with spliceosome complexes as they assemble on the nascent transcript. If this phenomenon is conserved in higher eukaryotes, it has the potential to be important for cotranscriptional regulation of alternative splicing.
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Affiliation(s)
- Isabella E Maudlin
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Jean D Beggs
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
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125
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Hardwick SA, Joglekar A, Flicek P, Frankish A, Tilgner HU. Getting the Entire Message: Progress in Isoform Sequencing. Front Genet 2019; 10:709. [PMID: 31475029 PMCID: PMC6706457 DOI: 10.3389/fgene.2019.00709] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 07/04/2019] [Indexed: 01/31/2023] Open
Abstract
The advent of second-generation sequencing and its application to RNA sequencing have revolutionized the field of genomics by allowing quantification of gene expression, as well as the definition of transcription start/end sites, exons, splice sites and RNA editing sites. However, due to the sequencing of fragments of cDNAs, these methods have not given a reliable picture of complete RNA isoforms. Third-generation sequencing has filled this gap and allows end-to-end sequencing of entire RNA/cDNA molecules. This approach to transcriptomics has been a "niche" technology for a couple of years but now is becoming mainstream with many different applications. Here, we review the background and progress made to date in this rapidly growing field. We start by reviewing the progressive realization that alternative splicing is omnipresent. We then focus on long-noncoding RNA isoforms and the distinct combination patterns of exons in noncoding and coding genes. We consider the implications of the recent technologies of direct RNA sequencing and single-cell isoform RNA sequencing. Finally, we discuss the parameters that define the success of long-read RNA sequencing experiments and strategies commonly used to make the most of such data.
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Affiliation(s)
- Simon A. Hardwick
- Brain and Mind Research Institute, Weill Cornell Medicine, NY, United States
- Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Anoushka Joglekar
- Brain and Mind Research Institute, Weill Cornell Medicine, NY, United States
| | - Paul Flicek
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, United Kingdom
| | - Adam Frankish
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, United Kingdom
| | - Hagen U. Tilgner
- Brain and Mind Research Institute, Weill Cornell Medicine, NY, United States
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126
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A novel enhancer RNA, Hmrhl, positively regulates its host gene, phkb, in chronic myelogenous leukemia. Noncoding RNA Res 2019; 4:96-108. [PMID: 31891018 PMCID: PMC6926186 DOI: 10.1016/j.ncrna.2019.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/09/2019] [Accepted: 08/01/2019] [Indexed: 11/16/2022] Open
Abstract
Noncoding RNAs are increasingly being accredited with key roles in gene regulation during development and disease. Here we report the discovery and characterization of a novel long noncoding RNA, Hmrhl, which shares synteny and partial sequence similarity with the mouse lncRNA, Mrhl. The human homolog, Hmrhl, transcribed from intron 14 of phkb gene, is 5.5 kb in size, expressed in all tissues examined and is associated with chromatin. Analysis of Hmrhl locus using ENCODE database revealed that it exhibits hallmarks of enhancers like the open chromatin configuration, binding of transcription factors, enhancer specific histone signature etc. in the K562 Chronic Myelogenous Leukemia (CML) cells. We compared the expression of Hmrhl in the normal lymphoblast cell line, GM12878, with that of K562 cells and lymphoma samples and show that it is highly upregulated in leukemia as well as several cases of lymphoma. Further, we validated the enhancer properties of Hmrhl locus in K562 cells with the help of ChIP-qPCR and Luciferase assay. Moreover, siRNA mediated down-regulation of Hmrhl in K562 cells leads to a concomitant down regulation of its parent gene, phkb, showing that Hmrhl functions as an enhancer RNA and positively regulates its host gene, phkb, in chronic myelogenous leukemia. This study is significant in view of the fact that a better understanding of mechanism of gene regulation under normal conditions and its perturbation in cancer could in turn help in its therapeutic intervention through molecular medicine/RNA based drug discovery.
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127
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Neugebauer KM. Nascent RNA and the Coordination of Splicing with Transcription. Cold Spring Harb Perspect Biol 2019; 11:11/8/a032227. [PMID: 31371351 DOI: 10.1101/cshperspect.a032227] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
At each active protein-encoding gene, nascent RNA is tethered to the DNA axis by elongating RNA polymerase II (Pol II) and is continuously altered by splicing and other processing events during its synthesis. This review discusses the development of three major methods that enable us to track the conversion of precursor messenger RNA (pre-mRNA) to messenger RNA (mRNA) products in vivo: live-cell imaging, metabolic labeling of RNA, and RNA-seq of purified nascent RNA. These approaches are complementary, addressing distinct issues of transcription rates and intron lifetimes alongside spatial information regarding the gene position of Pol II at which spliceosomes act. The findings will be placed in the context of active transcription units, each of which-because of the presence of nascent RNA, Pol II, and features of the chromatin environment-will recruit a potentially gene-specific constellation of RNA binding proteins and processing machineries.
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Affiliation(s)
- Karla M Neugebauer
- Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
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128
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Shenasa H, Hertel KJ. Combinatorial regulation of alternative splicing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194392. [PMID: 31276857 DOI: 10.1016/j.bbagrm.2019.06.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 06/21/2019] [Accepted: 06/24/2019] [Indexed: 12/23/2022]
Abstract
The generation of protein coding mRNAs from pre-mRNA is a fundamental biological process that is required for gene expression. Alternative pre-mRNA splicing is responsible for much of the transcriptomic and proteomic diversity observed in higher order eukaryotes. Aberrations that disrupt regular alternative splicing patterns are known to cause human diseases, including various cancers. Alternative splicing is a combinatorial process, meaning many factors affect which two splice sites are ligated together. The features that dictate exon inclusion are comprised of splice site strength, intron-exon architecture, RNA secondary structure, splicing regulatory elements, promoter use and transcription speed by RNA polymerase and the presence of post-transcriptional nucleotide modifications. A comprehensive view of all of the factors that influence alternative splicing decisions is necessary to predict splicing outcomes and to understand the molecular basis of disease. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Hossein Shenasa
- Department of Microbiology and Molecular Genetics, University of California, Irvine, CA 92697, United States of America
| | - Klemens J Hertel
- Department of Microbiology and Molecular Genetics, University of California, Irvine, CA 92697, United States of America.
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129
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Overexpressed long noncoding RNA CRNDE with distinct alternatively spliced isoforms in multiple cancers. Front Med 2019; 13:330-343. [PMID: 29808251 DOI: 10.1007/s11684-017-0557-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 04/30/2017] [Indexed: 12/22/2022]
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130
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Viphakone N, Sudbery I, Griffith L, Heath CG, Sims D, Wilson SA. Co-transcriptional Loading of RNA Export Factors Shapes the Human Transcriptome. Mol Cell 2019; 75:310-323.e8. [PMID: 31104896 PMCID: PMC6675937 DOI: 10.1016/j.molcel.2019.04.034] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 02/25/2019] [Accepted: 04/29/2019] [Indexed: 11/29/2022]
Abstract
During gene expression, RNA export factors are mainly known for driving nucleo-cytoplasmic transport. While early studies suggested that the exon junction complex (EJC) provides a binding platform for them, subsequent work proposed that they are only recruited by the cap binding complex to the 5′ end of RNAs, as part of TREX. Using iCLIP, we show that the export receptor Nxf1 and two TREX subunits, Alyref and Chtop, are recruited to the whole mRNA co-transcriptionally via splicing but before 3′ end processing. Consequently, Alyref alters splicing decisions and Chtop regulates alternative polyadenylation. Alyref is recruited to the 5′ end of RNAs by CBC, and our data reveal subsequent binding to RNAs near EJCs. We demonstrate that eIF4A3 stimulates Alyref deposition not only on spliced RNAs close to EJC sites but also on single-exon transcripts. Our study reveals mechanistic insights into the co-transcriptional recruitment of mRNA export factors and how this shapes the human transcriptome. 5′ cap binding complex CBC acts as a transient landing pad for Alyref Alyref is deposited upstream of the exon-exon junction next to the EJC Alyref can be deposited on introns and regulate splicing Chtop is mainly deposited on 3′ UTRs and influences poly(A) site choices
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Affiliation(s)
- Nicolas Viphakone
- Sheffield Institute For Nucleic Acids (SInFoNiA) and Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK.
| | - Ian Sudbery
- Sheffield Institute For Nucleic Acids (SInFoNiA) and Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Llywelyn Griffith
- Sheffield Institute For Nucleic Acids (SInFoNiA) and Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Catherine G Heath
- Sheffield Institute For Nucleic Acids (SInFoNiA) and Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - David Sims
- MRC Computational Genomics Analysis and Training Programme (CGAT), MRC Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, OX3 9DS UK
| | - Stuart A Wilson
- Sheffield Institute For Nucleic Acids (SInFoNiA) and Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK.
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131
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Zuckerman B, Ulitsky I. Predictive models of subcellular localization of long RNAs. RNA (NEW YORK, N.Y.) 2019; 25:557-572. [PMID: 30745363 PMCID: PMC6467007 DOI: 10.1261/rna.068288.118] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 02/07/2019] [Indexed: 05/14/2023]
Abstract
Export to the cytoplasm is a key regulatory junction for both protein-coding mRNAs and long noncoding RNAs (lncRNAs), and cytoplasmic enrichment varies dramatically both within and between those groups. We used a new computational approach and RNA-seq data from human and mouse cells to quantify the genome-wide association between cytoplasmic/nuclear ratios of both gene groups and various factors, including expression levels, splicing efficiency, gene architecture, chromatin marks, and sequence elements. Splicing efficiency emerged as the main predictive factor, explaining up to a third of the variability in localization. Combination with other features allowed predictive models that could explain up to 45% of the variance for protein-coding genes and up to 34% for lncRNAs. Factors associated with localization were similar between lncRNAs and mRNAs with some important differences. Readily accessible features can thus be used to predict RNA localization.
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Affiliation(s)
- Binyamin Zuckerman
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Igor Ulitsky
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
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132
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Xiao S, Cao S, Huang Q, Xia L, Deng M, Yang M, Jia G, Liu X, Shi J, Wang W, Li Y, Liu S, Zhu H, Tan K, Luo Q, Zhong M, He C, Xia L. The RNA N 6-methyladenosine modification landscape of human fetal tissues. Nat Cell Biol 2019; 21:651-661. [PMID: 31036937 DOI: 10.1038/s41556-019-0315-4] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 03/15/2019] [Indexed: 12/14/2022]
Abstract
A single genome gives rise to diverse tissues through complex epigenomic mechanisms, including N6-methyladenosine (m6A), a widespread RNA modification that is implicated in many biological processes. Here, to explore the global landscape of m6A in human tissues, we generated 21 whole-transcriptome m6A methylomes across major fetal tissues using m6A sequencing. These data reveal dynamic m6A methylation, identify large numbers of tissue differential m6A modifications and indicate that m6A is positively correlated with gene expression homeostasis. We also report m6A methylomes of long intergenic non-coding RNA (lincRNA), finding that enhancer lincRNAs are enriched for m6A. Tissue m6A regions are often enriched for single nucleotide polymorphisms that are associated with the expression of quantitative traits and complex traits including common diseases, which may potentially affect m6A modifications. Finally, we find that m6A modifications preferentially occupy genes with CpG-rich promoters, features of which regulate RNA transcript m6A. Our data indicate that m6A is widely regulated by human genetic variation and promoters, suggesting a broad involvement of m6A in human development and disease.
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Affiliation(s)
- Shan Xiao
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Shuo Cao
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Qitao Huang
- Division of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Linjian Xia
- School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Mingqiang Deng
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Mengtian Yang
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Guiru Jia
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Xiaona Liu
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Junfang Shi
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Weishi Wang
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yuan Li
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Sun Liu
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Haoran Zhu
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Kaifen Tan
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Qizhi Luo
- Hygiene Detection Center, School of Public Health, Southern Medical University, Guangzhou, China
| | - Mei Zhong
- Division of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
| | - Chunjiang He
- School of Basic Medical Sciences, Wuhan University, Wuhan, China.
| | - Laixin Xia
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.
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133
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Bunch H, Choe H, Kim J, Jo DS, Jeon S, Lee S, Cho DH, Kang K. P-TEFb Regulates Transcriptional Activation in Non-coding RNA Genes. Front Genet 2019; 10:342. [PMID: 31068966 PMCID: PMC6491683 DOI: 10.3389/fgene.2019.00342] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/29/2019] [Indexed: 01/16/2023] Open
Abstract
Many non-coding RNAs (ncRNAs) serve as regulatory molecules in various physiological pathways, including gene expression in mammalian cells. Distinct from protein-coding RNA expression, ncRNA expression is regulated solely by transcription and RNA processing/stability. It is thus important to understand transcriptional regulation in ncRNA genes but is yet to be known completely. Previously, we identified that a subset of mammalian ncRNA genes is transcriptionally regulated by RNA polymerase II (Pol II) promoter-proximal pausing and in a tissue-specific manner. In this study, human ncRNA genes that are expressed in the early G1 phase, termed immediate early ncRNA genes, were monitored to assess the function of positive transcription elongation factor b (P-TEFb), a master Pol II pausing regulator for protein-coding genes, in ncRNA transcription. Our findings indicate that the expression of many ncRNA genes is induced in the G0–G1 transition and regulated by P-TEFb. Interestingly, a biphasic characteristic of P-TEFb-dependent transcription of serum responsive ncRNA genes was observed: Pol II carboxyl-terminal domain phosphorylated at serine 2 (S2) was largely increased in the transcription start site (TSS, -300 to +300) whereas overall, it was decreased in the gene body (GB, > +350) upon chemical inhibition of P-TEFb. In addition, the three representative, immediate early ncRNAs, whose expression is dependent on P-TEFb, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), nuclear enriched abundant transcript 1 (NEAT1), and X-inactive specific transcript (XIST), were further analyzed for determining P-TEFb association. Taken together, our data suggest that transcriptional activation of many human ncRNAs utilizes the pausing and releasing of Pol II, and that the regulatory mechanism of transcriptional elongation in these genes requires the function of P-TEFb. Furthermore, we propose that ncRNA and mRNA transcription are regulated by similar mechanisms while P-TEFb inhibition unexpectedly increases S2 Pol II phosphorylation in the TSSs in many ncRNA genes. One Sentence Summary: P-TEFb regulates Pol II phosphorylation for transcriptional activation in many stimulus-inducible ncRNA genes.
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Affiliation(s)
- Heeyoun Bunch
- Department of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Hyeseung Choe
- Department of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Jongbum Kim
- Department of Transcriptome & Epigenome, Macrogen Incorporated, Seoul, South Korea
| | - Doo Sin Jo
- Institute of Life Science and Biotechnology, College of Natural Science, Kyungpook National University, Daegu, South Korea
| | - Soyeon Jeon
- Department of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Sanghwa Lee
- Department of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Dong-Hyung Cho
- Department of Life Science, College of Natural Science, Kyungpook National University, Daegu, South Korea
| | - Keunsoo Kang
- Department of Microbiology, College of Natural Sciences, Dankook University, Cheonan, South Korea
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134
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Peck SA, Hughes KD, Victorino JF, Mosley AL. Writing a wrong: Coupled RNA polymerase II transcription and RNA quality control. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1529. [PMID: 30848101 PMCID: PMC6570551 DOI: 10.1002/wrna.1529] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 12/27/2018] [Accepted: 02/07/2019] [Indexed: 12/20/2022]
Abstract
Processing and maturation of precursor RNA species is coupled to RNA polymerase II transcription. Co-transcriptional RNA processing helps to ensure efficient and proper capping, splicing, and 3' end processing of different RNA species to help ensure quality control of the transcriptome. Many improperly processed transcripts are not exported from the nucleus, are restricted to the site of transcription, and are in some cases degraded, which helps to limit any possibility of aberrant RNA causing harm to cellular health. These critical quality control pathways are regulated by the highly dynamic protein-protein interaction network at the site of transcription. Recent work has further revealed the extent to which the processes of transcription and RNA processing and quality control are integrated, and how critically their coupling relies upon the dynamic protein interactions that take place co-transcriptionally. This review focuses specifically on the intricate balance between 3' end processing and RNA decay during transcription termination. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Processing > 3' End Processing RNA Processing > Splicing Mechanisms RNA Processing > Capping and 5' End Modifications.
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Affiliation(s)
- Sarah A Peck
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Katlyn D Hughes
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Jose F Victorino
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
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135
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Nozawa RS, Gilbert N. RNA: Nuclear Glue for Folding the Genome. Trends Cell Biol 2019; 29:201-211. [DOI: 10.1016/j.tcb.2018.12.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 12/10/2018] [Accepted: 12/14/2018] [Indexed: 12/20/2022]
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136
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Ragan C, Goodall GJ, Shirokikh NE, Preiss T. Insights into the biogenesis and potential functions of exonic circular RNA. Sci Rep 2019; 9:2048. [PMID: 30765711 PMCID: PMC6376117 DOI: 10.1038/s41598-018-37037-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 12/03/2018] [Indexed: 01/16/2023] Open
Abstract
Circular RNAs (circRNAs) exhibit unique properties due to their covalently closed nature. Models of circRNAs synthesis and function are emerging but much remains undefined about this surprisingly prevalent class of RNA. Here, we identified exonic circRNAs from human and mouse RNA-sequencing datasets, documenting multiple new examples. Addressing function, we found that many circRNAs co-sediment with ribosomes, indicative of their translation potential. By contrast, circRNAs with potential to act as microRNA sponges were scarce, with some support for a collective sponge function by groups of circRNAs. Addressing circRNA biogenesis, we delineated several features commonly associated with circRNA occurrence. CircRNA-producing genes tend to be longer and to contain more exons than average. Back-splice acceptor exons are strongly enriched at ordinal position 2 within genes, and circRNAs typically have a short exon span with two exons being the most prevalent. The flanking introns either side of circRNA loci are exceptionally long. Of note also, single-exon circRNAs derive from unusually long exons while multi-exon circRNAs are mostly generated from exons of regular length. These findings independently validate and extend similar observations made in a number of prior studies. Furthermore, we analysed high-resolution RNA polymerase II occupancy data from two separate human cell lines to reveal distinctive transcription dynamics at circRNA-producing genes. Specifically, RNA polymerase II traverses the introns of these genes at above average speed concomitant with an accentuated slow-down at exons. Collectively, these features indicate how a perturbed balance between transcription and linear splicing creates important preconditions for circRNA production. We speculate that these preconditions need to be in place so that looping interactions between flanking introns can promote back-splicing to raise circRNA production to appreciable levels.
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Affiliation(s)
- Chikako Ragan
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia
| | - Gregory J Goodall
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, 5000, Australia
- Discipline of Medicine, The University of Adelaide, Adelaide, SA, 5005, Australia
- School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Nikolay E Shirokikh
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia.
| | - Thomas Preiss
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia.
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, 2010, Australia.
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137
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Promoter-proximal pausing mediated by the exon junction complex regulates splicing. Nat Commun 2019; 10:521. [PMID: 30705266 PMCID: PMC6355915 DOI: 10.1038/s41467-019-08381-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 01/04/2019] [Indexed: 02/08/2023] Open
Abstract
Promoter-proximal pausing of RNA polymerase II (Pol II) is a widespread transcriptional regulatory step across metazoans. Here we find that the nuclear exon junction complex (pre-EJC) is a critical and conserved regulator of this process. Depletion of pre-EJC subunits leads to a global decrease in Pol II pausing and to premature entry into elongation. This effect occurs, at least in part, via non-canonical recruitment of pre-EJC components at promoters. Failure to recruit the pre-EJC at promoters results in increased binding of the positive transcription elongation complex (P-TEFb) and in enhanced Pol II release. Notably, restoring pausing is sufficient to rescue exon skipping and the photoreceptor differentiation defect associated with depletion of pre-EJC components in vivo. We propose that the pre-EJC serves as an early transcriptional checkpoint to prevent premature entry into elongation, ensuring proper recruitment of RNA processing components that are necessary for exon definition.
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138
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Krchňáková Z, Thakur PK, Krausová M, Bieberstein N, Haberman N, Müller-McNicoll M, Staněk D. Splicing of long non-coding RNAs primarily depends on polypyrimidine tract and 5' splice-site sequences due to weak interactions with SR proteins. Nucleic Acids Res 2019; 47:911-928. [PMID: 30445574 PMCID: PMC6344860 DOI: 10.1093/nar/gky1147] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 10/26/2018] [Accepted: 10/30/2018] [Indexed: 12/20/2022] Open
Abstract
Many nascent long non-coding RNAs (lncRNAs) undergo the same maturation steps as pre-mRNAs of protein-coding genes (PCGs), but they are often poorly spliced. To identify the underlying mechanisms for this phenomenon, we searched for putative splicing inhibitory sequences using the ncRNA-a2 as a model. Genome-wide analyses of intergenic lncRNAs (lincRNAs) revealed that lincRNA splicing efficiency positively correlates with 5'ss strength while no such correlation was identified for PCGs. In addition, efficiently spliced lincRNAs have higher thymidine content in the polypyrimidine tract (PPT) compared to efficiently spliced PCGs. Using model lincRNAs, we provide experimental evidence that strengthening the 5'ss and increasing the T content in PPT significantly enhances lincRNA splicing. We further showed that lincRNA exons contain less putative binding sites for SR proteins. To map binding of SR proteins to lincRNAs, we performed iCLIP with SRSF2, SRSF5 and SRSF6 and analyzed eCLIP data for SRSF1, SRSF7 and SRSF9. All examined SR proteins bind lincRNA exons to a much lower extent than expression-matched PCGs. We propose that lincRNAs lack the cooperative interaction network that enhances splicing, which renders their splicing outcome more dependent on the optimality of splice sites.
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Affiliation(s)
- Zuzana Krchňáková
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Prasoon Kumar Thakur
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Michaela Krausová
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Nicole Bieberstein
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Nejc Haberman
- Computational Regulatory Genomics, MRC London Institute of Medical Sciences, London W12 0NN, UK
| | | | - David Staněk
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
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139
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Carrocci TJ, Neugebauer KM. Pre-mRNA Splicing in the Nuclear Landscape. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2019; 84:11-20. [PMID: 32493763 PMCID: PMC7384967 DOI: 10.1101/sqb.2019.84.040402] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Eukaryotic gene expression requires the cumulative activity of multiple molecular machines to synthesize and process newly transcribed pre-messenger RNA. Introns, the noncoding regions in pre-mRNA, must be removed by the spliceosome, which assembles on the pre-mRNA as it is transcribed by RNA polymerase II (Pol II). The assembly and activity of the spliceosome can be modulated by features including the speed of transcription elongation, chromatin, post-translational modifications of Pol II and histone tails, and other RNA processing events like 5'-end capping. Here, we review recent work that has revealed cooperation and coordination among co-transcriptional processing events and speculate on new avenues of research. We anticipate new mechanistic insights capable of unraveling the relative contribution of coupled processing to gene expression.
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Affiliation(s)
- Tucker J Carrocci
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
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140
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Godoy Herz MA, Kornblihtt AR. Alternative Splicing and Transcription Elongation in Plants. FRONTIERS IN PLANT SCIENCE 2019; 10:309. [PMID: 30972082 PMCID: PMC6443983 DOI: 10.3389/fpls.2019.00309] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 02/26/2019] [Indexed: 05/19/2023]
Abstract
Alternative splicing and transcription elongation by RNA polymerase II (RNAPII) are two processes which are tightly connected. Splicing is a co-transcriptional process, and different experimental approaches show that splicing is coupled to transcription in Drosophila, yeast and mammals. However, little is known about coupling of transcription and alternative splicing in plants. The kinetic coupling explains how changes in RNAPII elongation rate influence alternative splicing choices. Recent work in Arabidopsis shows that expression of a dominant negative transcription elongation factor, TFIIS, enhances exon inclusion. Furthermore, the Arabidopsis transcription elongation complex has been recently described, providing new information about elongation factors that interact with elongating RNAPII. Light regulates alternative splicing in plants through a chloroplast retrograde signaling. We have recently shown that light promotes RNAPII elongation in the affected genes, while in darkness elongation is lower. These changes in transcription are consistent with elongation causing the observed changes in alternative splicing. Altogether, these findings provide evidence that coupling between transcription and alternative splicing is an important layer of gene expression regulation in plants.
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Affiliation(s)
- Micaela A. Godoy Herz
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-UBA, Buenos Aires, Argentina
| | - Alberto R. Kornblihtt
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-UBA, Buenos Aires, Argentina
- *Correspondence: Alberto R. Kornblihtt,
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141
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Abstract
Noncoding RNAs (ncRNAs) have received much attention due to their central role in gene expression and translational regulation as well as due to their involvement in several biological processes and disease development. Small noncoding RNAs (sncRNAs), such as microRNAs and piwiRNAs, have been thoroughly investigated and functionally characterized. Long noncoding RNAs (lncRNAs), known to play an important role in chromatin-interacting transcription regulation, posttranscriptional regulation, cell-to-cell signaling, and protein regulation, are also being investigated to further elucidate their functional roles.Next-generation sequencing (NGS) technologies have greatly aided in characterizing the ncRNAome. Moreover, the coupling of NGS technology together with bioinformatics tools has been essential to the genome-wide detection of RNA modifications in ncRNAs. RNA editing, a common human co-transcriptional and posttranscriptional modification, is a dynamic biological phenomenon able to alter the sequence and the structure of primary transcripts (both coding and noncoding RNAs) during the maturation process, consequently influencing the biogenesis, as well as the function, of ncRNAs. In particular, the dysregulation of the RNA editing machineries have been associated with the onset of human diseases.In this chapter we discuss the potential functions of ncRNA editing and describe the knowledge base and bioinformatics resources available to investigate such phenomenon.
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142
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Abstract
At the beginning of this century, the Human Genome Project produced the first drafts of the human genome sequence. Following this, large-scale functional genomics studies were initiated to understand the molecular basis underlying the translation of the instructions encoded in the genome into the biological traits of organisms. Instrumental in the ensuing revolution in functional genomics were the rapid advances in massively parallel sequencing technologies as well as the development of a wide diversity of protocols that make use of these technologies to understand cellular behavior at the molecular level. Here, we review recent advances in functional genomic methods, discuss some of their current capabilities and limitations, and briefly sketch future directions within the field.
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Affiliation(s)
- Roderic Guigo
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain
| | - Michiel de Hoon
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
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143
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Yazarlou F, Modarressi MH, Mowla SJ, Oskooei VK, Motevaseli E, Tooli LF, Nekoohesh L, Eghbali M, Ghafouri-Fard S, Afsharpad M. Urinary exosomal expression of long non-coding RNAs as diagnostic marker in bladder cancer. Cancer Manag Res 2018; 10:6357-6365. [PMID: 30568497 PMCID: PMC6267766 DOI: 10.2147/cmar.s186108] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Background Long non-coding RNAs (lncRNAs) and exosomes have been regarded as components of cell signal transmission that modulate indigenous cellular microenvironments. Exosomes also participate in relocation of functional lncRNAs between cells. Methods In the present study, we evaluated expression of LINC00355, LINC00958, UCA1-201, UCA1-203, and MALAT1 lncRNAs in urinary exosomes isolated from transitional cell carcinoma (TCC) of bladder, non-malignant urinary disorders, and normal subjects. Results LINC00355, UCA1-203, and MALAT1 expression was significantly higher in TCC patients compared to controls (non-malignant or normal samples). However, UCA1-201 expression was significantly decreased in TCC patients compared with controls. LINC00355 and MALAT1 expression was significantly lower in cigarette smokers and opium-addicted TCC patients, respectively. On the other hand, LINC00355 expression tended to be higher in opium-addicted TCC patients. The proposed panel of lncRNAs (composed of UCA1-201, UCA1-203, MALAT1, and LINC00355) had 92% sensitivity and 91.7% specificity for diagnosis of bladder cancer from normal samples. Conclusion Transcript levels of lncRNAs in urinary exosomes are potential diagnostic bio-markers in bladder cancer.
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Affiliation(s)
- Fatemeh Yazarlou
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Seyed Javad Mowla
- Faculty of Biological Sciences, Department of Genetics, Tarbiat Modares University, Tehran, Iran
| | - Vahid Kholghi Oskooei
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran,
| | - Elahe Motevaseli
- Department of Molecular Medicine, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Leila Farhady Tooli
- Department of Microbiology, School of Biology, College of Science, Tehran University, Tehran, Iran
| | - Leila Nekoohesh
- Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Eghbali
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Soudeh Ghafouri-Fard
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran,
| | - Mandana Afsharpad
- Cancer Control Research Center, Cancer Control Foundation, Iran University of Medical Sciences, Tehran, Iran,
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144
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Li B, Ma L, Zhang C, Zhou Z, Yuan H, Jiang H, Pan Y, Tan Q. Associations of genetic variants in endocytic trafficking of epidermal growth factor receptor super pathway with risk of nonsyndromic cleft lip with or without cleft palate. Mol Genet Genomic Med 2018; 6:1157-1167. [PMID: 30411541 PMCID: PMC6305670 DOI: 10.1002/mgg3.497] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/03/2018] [Accepted: 10/02/2018] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The genetic etiology of nonsyndromic cleft lip with or without cleft palate (NSCL/P) has not been fully clarified to date. Epidermal growth factor receptor (EGFR) was reportedly involved in its biological establishment and regulation of cell migration during the embryonic stage. METHODS We selected a super pathway of endocytic trafficking of EGFR and investigated the associations of single-nucleotide polymorphisms (SNPs) in the super pathway with the risk of NSCL/P by analyzing our published genome-wide association study (GWAS) data from 504 NSCL/P individuals and 455 controls. After the false discovery rate (FDR) control, we conducted linkage disequilibrium (LD) analyses and conditional regression analyses to obtain independent lead SNPs. We performed LD analyses between the lead SNPs and the reported SNPs to find novel ones from our study. We annotated the lead SNPs and investigated their mapped genes in silico. RESULTS A total of 82 SNPs showed a statistical association with the risk of NSCL/P after FDR control. They contained three reported SNPs which were g.117068049G>A (rs7078160), g.117086783C>G (rs10886040), and g.117101266G>T (rs17095681). Four independent lead SNPs were obtained, including g.116979803 T>C (rs1905539) and g.117037960A>G (rs7902502) at 10q25.3, g.35720163G>C (rs75656820) at 17q12, and g.156864512G>A (rs1800877) at 1q23.1. Three of them were in low LD (r2 < 0.5) with the reported SNPs except g.117037960A>G (rs7902502), so these three were newly identified. Lead SNPs were mapped to three genes: SHTN1, AP2B1, and NTRK1. The three genes were relatively more highly expressed in the human craniofacial region and in the proximal maxillary location during the craniofacial development stage of the embryonic mouse. CONCLUSION Our results suggested that SHTN1, AP2B1, and NTRK1 might be associated with the development of NSCL/P.
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Affiliation(s)
- Bing Li
- Department of Burns and Plastic Surgery, The Drum Tower Clinical Medical College, Nanjing Medical University, Nanjing, China.,Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China
| | - Lan Ma
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China
| | - Chi Zhang
- Department of Orthodontics, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China
| | - Zhixuan Zhou
- Department of Polyclinic, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China
| | - Hua Yuan
- Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China.,Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China
| | - Hongbing Jiang
- Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China.,Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China
| | - Yongchu Pan
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China.,Department of Orthodontics, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China.,State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Qian Tan
- Department of Burns and Plastic Surgery, The Drum Tower Clinical Medical College, Nanjing Medical University, Nanjing, China.,Department of Burns and Plastic Surgery, Affiliated Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
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145
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Hansen MMK, Desai RV, Simpson ML, Weinberger LS. Cytoplasmic Amplification of Transcriptional Noise Generates Substantial Cell-to-Cell Variability. Cell Syst 2018; 7:384-397.e6. [PMID: 30243562 PMCID: PMC6202163 DOI: 10.1016/j.cels.2018.08.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/14/2018] [Accepted: 08/02/2018] [Indexed: 12/15/2022]
Abstract
Transcription is an episodic process characterized by probabilistic bursts, but how the transcriptional noise from these bursts is modulated by cellular physiology remains unclear. Using simulations and single-molecule RNA counting, we examined how cellular processes influence cell-to-cell variability (noise). The results show that RNA noise is higher in the cytoplasm than the nucleus in ∼85% of genes across diverse promoters, genomic loci, and cell types (human and mouse). Measurements show further amplification of RNA noise in the cytoplasm, fitting a model of biphasic mRNA conversion between translation- and degradation-competent states. This multi-state translation-degradation of mRNA also causes substantial noise amplification in protein levels, ultimately accounting for ∼74% of intrinsic protein variability in cell populations. Overall, the results demonstrate how noise from transcriptional bursts is intrinsically amplified by mRNA processing, leading to a large super-Poissonian variability in protein levels.
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Affiliation(s)
- Maike M K Hansen
- Gladstone|UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Ravi V Desai
- Gladstone|UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Michael L Simpson
- Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Leor S Weinberger
- Gladstone|UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA; Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
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146
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Palazzo AF, Lee ES. Sequence Determinants for Nuclear Retention and Cytoplasmic Export of mRNAs and lncRNAs. Front Genet 2018; 9:440. [PMID: 30386371 PMCID: PMC6199362 DOI: 10.3389/fgene.2018.00440] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 09/14/2018] [Indexed: 11/26/2022] Open
Abstract
Eukaryotes are divided into two major compartments: the nucleus where RNA is synthesized and processed, and the cytoplasm, where mRNA is translated into proteins. Although many different RNAs are made, only a subset is allowed access to the cytoplasm, primarily RNAs involved in protein synthesis (mRNA, tRNA, and rRNA). In contrast, nuclear retained transcripts are mostly long non-coding RNAs (lncRNAs) whose role in cell physiology has been a source of much investigation in the past few years. In addition, it is likely that many non-functional RNAs, which arise by spurious transcription and misprocessing of functional RNAs, are also retained in the nucleus and degraded. In this review, the main sequence features that dictate whether any particular mRNA or lncRNA is a substrate for retention in the nucleus, or export to the cytoplasm, are discussed. Although nuclear export is promoted by RNA-splicing due to the fact that the spliceosome can help recruit export factors to the mature RNA, nuclear export does not require splicing. Indeed, most stable unspliced transcripts are well exported and associate with these same export factors in a splicing-independent manner. In contrast, nuclear retention is promoted by specialized cis-elements found in certain RNAs. This new understanding of the determinants of nuclear retention and cytoplasmic export provides a deeper understanding of how information flow is regulated in eukaryotic cells. Ultimately these processes promote the evolution of complexity in eukaryotes by shaping the genomic content through constructive neutral evolution.
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147
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Chen W, Feng P, Ding H, Lin H. Classifying Included and Excluded Exons in Exon Skipping Event Using Histone Modifications. Front Genet 2018; 9:433. [PMID: 30327665 PMCID: PMC6174203 DOI: 10.3389/fgene.2018.00433] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 09/12/2018] [Indexed: 12/15/2022] Open
Abstract
Alternative splicing (AS) not only ensures the diversity of gene expression products, but also closely correlated with genetic diseases. Therefore, knowledge about regulatory mechanisms of AS will provide useful clues for understanding its biological functions. In the current study, a random forest based method was developed to classify included and excluded exons in exon skipping event. In this method, the samples in the dataset were encoded by using optimal histone modification features which were optimized by using the Maximum Relevance Maximum Distance (MRMD) feature selection technique. The proposed method obtained an accuracy of 72.91% in 10-fold cross validation test and outperformed existing methods. Meanwhile, we also systematically analyzed the distribution of histone modifications between included and excluded exons and discovered their preference in both kinds of exons, which might provide insights into researches on the regulatory mechanisms of alternative splicing.
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Affiliation(s)
- Wei Chen
- Center for Genomics and Computational Biology, School of Life Science, North China University of Science and Technology, Tangshan, China.,Innovative Institute of Chinese Medicine and Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Pengmian Feng
- School of Public Health, North China University of Science and Technology, Tangshan, China
| | - Hui Ding
- Key Laboratory for Neuro-Information of Ministry of Education, Center of Bioinformatics and Center for Information in Biomedicine, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Hao Lin
- Key Laboratory for Neuro-Information of Ministry of Education, Center of Bioinformatics and Center for Information in Biomedicine, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
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148
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Biamonti G, Maita L, Montecucco A. The Krebs Cycle Connection: Reciprocal Influence Between Alternative Splicing Programs and Cell Metabolism. Front Oncol 2018; 8:408. [PMID: 30319972 PMCID: PMC6168629 DOI: 10.3389/fonc.2018.00408] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 09/06/2018] [Indexed: 12/14/2022] Open
Abstract
Alternative splicing is a pervasive mechanism that molds the transcriptome to meet cell and organism needs. However, how this layer of gene expression regulation is coordinated with other aspects of the cell metabolism is still largely undefined. Glucose is the main energy and carbon source of the cell. Not surprisingly, its metabolism is finely tuned to satisfy growth requirements and in response to nutrient availability. A number of studies have begun to unveil the connections between glucose metabolism and splicing programs. Alternative splicing modulates the ratio between M1 and M2 isoforms of pyruvate kinase in this way determining the choice between aerobic glycolysis and complete glucose oxidation in the Krebs cycle. Reciprocally, intermediates in the Krebs cycle may impact splicing programs at different levels by modulating the activity of 2-oxoglutarate-dependent oxidases. In this review we discuss the molecular mechanisms that coordinate alternative splicing programs with glucose metabolism, two aspects with profound implications in human diseases.
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Affiliation(s)
- Giuseppe Biamonti
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy
| | - Lucia Maita
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy
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149
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Martinez NM, Gilbert WV. Pre-mRNA modifications and their role in nuclear processing. QUANTITATIVE BIOLOGY 2018; 6:210-227. [PMID: 30533247 DOI: 10.1007/s40484-018-0147-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Background Cellular non-coding RNAs are extensively modified post-transcriptionally, with more than 100 chemically distinct nucleotides identified to date. In the past five years, new sequencing based methods have revealed widespread decoration of eukaryotic messenger RNA with diverse RNA modifications whose functions in mRNA metabolism are only beginning to be known. Results Since most of the identified mRNA modifying enzymes are present in the nucleus, these modifications have the potential to function in nuclear pre-mRNA processing including alternative splicing. Here we review recent progress towards illuminating the role of pre-mRNA modifications in splicing and highlight key areas for future investigation in this rapidly growing field. Conclusions Future studies to identify which modifications are added to nascent pre-mRNA and to interrogate the direct effects of individual modifications are likely to reveal new mechanisms by which nuclear pre-mRNA processing is regulated.
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Affiliation(s)
- Nicole M Martinez
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Wendy V Gilbert
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520, USA
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150
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Wang Y, Wang Z, Liu T, Gong S, Zhang W. Effects of flanking regions on HDV cotranscriptional folding kinetics. RNA (NEW YORK, N.Y.) 2018; 24:1229-1240. [PMID: 29954950 PMCID: PMC6097654 DOI: 10.1261/rna.065961.118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/25/2018] [Indexed: 05/20/2023]
Abstract
Hepatitis delta virus (HDV) ribozyme performs the self-cleavage activity through folding to a double pseudoknot structure. The folding of functional RNA structures is often coupled with the transcription process. In this work, we developed a new approach for predicting the cotranscriptional folding kinetics of RNA secondary structures with pseudoknots. We theoretically studied the cotranscriptional folding behavior of the 99-nucleotide (nt) HDV sequence, two upstream flanking sequences, and one downstream flanking sequence. During transcription, the 99-nt HDV can effectively avoid the trap intermediates and quickly fold to the cleavage-active state. It is different from its refolding kinetics, which folds into an intermediate trap state. For all the sequences, the ribozyme regions (from 1 to 73) all fold to the same structure during transcription. However, the existence of the 30-nt upstream flanking sequence can inhibit the ribozyme region folding into the active native state through forming an alternative helix Alt1 with the segments 70-90. The longer upstream flanking sequence of 54 nt itself forms a stable hairpin structure, which sequesters the formation of the Alt1 helix and leads to rapid formation of the cleavage-active structure. Although the 55-nt downstream flanking sequence could invade the already folded active structure during transcription by forming a more stable helix with the ribozyme region, the slow transition rate could keep the structure in the cleavage-active structure to perform the activity.
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Affiliation(s)
- Yanli Wang
- Department of Physics, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Zhen Wang
- Department of Physics, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Taigang Liu
- Department of Physics, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Sha Gong
- Department of Physics, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Wenbing Zhang
- Department of Physics, Wuhan University, Wuhan, Hubei 430072, P.R. China
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