51
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David JK, Maden SK, Wood MA, Thompson RF, Nellore A. Retained introns in long RNA-seq reads are not reliably detected in sample-matched short reads. Genome Biol 2022; 23:240. [PMID: 36369064 PMCID: PMC9652823 DOI: 10.1186/s13059-022-02789-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 10/10/2022] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND There is growing interest in retained introns in a variety of disease contexts including cancer and aging. Many software tools have been developed to detect retained introns from short RNA-seq reads, but reliable detection is complicated by overlapping genes and transcripts as well as the presence of unprocessed or partially processed RNAs. RESULTS We compared introns detected by 8 tools using short RNA-seq reads with introns observed in long RNA-seq reads from the same biological specimens. We found significant disagreement among tools (Fleiss' [Formula: see text]) such that 47.7% of all detected intron retentions were not called by more than one tool. We also observed poor performance of all tools, with none achieving an F1-score greater than 0.26, and qualitatively different behaviors between general-purpose alternative splicing detection tools and tools confined to retained intron detection. CONCLUSIONS Short-read tools detect intron retention with poor recall and precision, calling into question the completeness and validity of a large percentage of putatively retained introns called by commonly used methods.
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Affiliation(s)
- Julianne K. David
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA ,Present Address: Base5 Genomics, Inc., Mountain View, CA USA
| | - Sean K. Maden
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA ,grid.21107.350000 0001 2171 9311Present Address: Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA
| | - Mary A. Wood
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.429936.30000 0004 5914 210XPortland VA Research Foundation, Portland, OR USA ,Present Address: Phase Genomics, Inc., Seattle, WA USA
| | - Reid F. Thompson
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA ,grid.484322.bDivision of Hospital and Specialty Medicine, VA Portland Healthcare System, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Radiation Medicine, Oregon Health & Science University, Portland, OR USA
| | - Abhinav Nellore
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Surgery, Oregon Health & Science University, Portland, OR USA
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52
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Ponting CP, Haerty W. Genome-Wide Analysis of Human Long Noncoding RNAs: A Provocative Review. Annu Rev Genomics Hum Genet 2022; 23:153-172. [PMID: 35395170 DOI: 10.1146/annurev-genom-112921-123710] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Do long noncoding RNAs (lncRNAs) contribute little or substantively to human biology? To address how lncRNA loci and their transcripts, structures, interactions, and functions contribute to human traits and disease, we adopt a genome-wide perspective. We intend to provoke alternative interpretation of questionable evidence and thorough inquiry into unsubstantiated claims. We discuss pitfalls of lncRNA experimental and computational methods as well as opposing interpretations of their results. The majority of evidence, we argue, indicates that most lncRNA transcript models reflect transcriptional noise or provide minor regulatory roles, leaving relatively few human lncRNAs that contribute centrally to human development, physiology, or behavior. These important few tend to be spliced and better conserved but lack a simple syntax relating sequence to structure and mechanism, and so resist simple categorization. This genome-wide view should help investigators prioritize individual lncRNAs based on their likely contribution to human biology.
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Affiliation(s)
- Chris P Ponting
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom;
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53
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Zamani M, Foroughmand AM, Hajjari MR, Bakhshinejad B, Johnson R, Galehdari H. CASC11 and PVT1 spliced transcripts play an oncogenic role in colorectal carcinogenesis. Front Oncol 2022; 12:954634. [PMID: 36052265 PMCID: PMC9424822 DOI: 10.3389/fonc.2022.954634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Cancer is fundamentally a genetic disorder that alters cellular information flow toward aberrant growth. The coding part accounts for less than 2% of the human genome, and it has become apparent that aberrations within the noncoding genome drive important cancer phenotypes. The numerous carcinogenesis-related genomic variations in the 8q24 region include single nucleotide variations (SNVs), copy number variations (CNVs), and viral integrations occur in the neighboring areas of the MYC locus. It seems that MYC is not the only target of these alterations. The MYC-proximal mutations may act via regulatory noncoding RNAs (ncRNAs). In this study, gene expression analyses indicated that the expression of some PVT1 spliced linear transcripts, CircPVT1, CASC11, and MYC is increased in colorectal cancer (CRC). Moreover, the expression of these genes is associated with some clinicopathological characteristics of CRC. Also, in vitro studies in CRC cell lines demonstrated that CASC11 is mostly detected in the nucleus, and different transcripts of PVT1 have different preferences for nuclear and cytoplasmic parts. Furthermore, perturbation of PVT1 expression and concomitant perturbation in PVT1 and CASC11 expression caused MYC overexpression. It seems that transcription of MYC is under regulatory control at the transcriptional level, i.e., initiation and elongation of transcription by its neighboring genes. Altogether, the current data provide evidence for the notion that these noncoding transcripts can significantly participate in the MYC regulation network and in the carcinogenesis of colorectal cells.
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Affiliation(s)
- Mina Zamani
- Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | | | - Mohammad-Reza Hajjari
- Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Babak Bakhshinejad
- Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Rory Johnson
- Department of Medical Oncology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department for BioMedical Research, University of Bern, Bern, Switzerland
- School of Biology and Environmental Science, University College Dublin, Dublin, Ireland
- Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Hamid Galehdari
- Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran
- *Correspondence: Hamid Galehdari,
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54
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Comprehensive analysis of the circadian nuclear and cytoplasmic transcriptome in mouse liver. PLoS Genet 2022; 18:e1009903. [PMID: 35921362 PMCID: PMC9377612 DOI: 10.1371/journal.pgen.1009903] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 08/15/2022] [Accepted: 07/06/2022] [Indexed: 11/19/2022] Open
Abstract
In eukaryotes, RNA is synthesised in the nucleus, spliced, and exported to the cytoplasm where it is translated and finally degraded. Any of these steps could be subject to temporal regulation during the circadian cycle, resulting in daily fluctuations of RNA accumulation and affecting the distribution of transcripts in different subcellular compartments. Our study analysed the nuclear and cytoplasmic, poly(A) and total transcriptomes of mouse livers collected over the course of a day. These data provide a genome-wide temporal inventory of enrichment in subcellular RNA, and revealed specific signatures of splicing, nuclear export and cytoplasmic mRNA stability related to transcript and gene lengths. Combined with a mathematical model describing rhythmic RNA profiles, we could test the rhythmicity of export rates and cytoplasmic degradation rates of approximately 1400 genes. With nuclear export times usually much shorter than cytoplasmic half-lives, we found that nuclear export contributes to the modulation and generation of rhythmic profiles of 10% of the cycling nuclear mRNAs. This study contributes to a better understanding of the dynamic regulation of the transcriptome during the day-night cycle.
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55
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Magnuson B, Bedi K, Narayanan IV, Bartkowiak B, Blinkiewicz H, Paulsen MT, Greenleaf A, Ljungman M. CDK12 regulates co-transcriptional splicing and RNA turnover in human cells. iScience 2022; 25:105030. [PMID: 36111258 PMCID: PMC9468413 DOI: 10.1016/j.isci.2022.105030] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/13/2022] [Accepted: 08/23/2022] [Indexed: 11/28/2022] Open
Abstract
The cyclin-dependent kinase CDK12 has garnered interest as a cancer therapeutic target as DNA damage response genes are particularly suppressed by loss of CDK12 activity. In this study, we assessed the acute effects of CDK12 inhibition on transcription and RNA processing using nascent RNA Bru-seq and BruChase-seq. Acute transcriptional changes were overall small after CDK12 inhibition but over 600 genes showed intragenic premature termination, including DNA repair and cell cycle genes. Furthermore, many genes showed reduced transcriptional readthrough past the end of genes in the absence of CDK12 activity. RNA turnover was dramatically affected by CDK12 inhibition and importantly, caused increased degradation of many transcripts from DNA damage response genes. We also show that co-transcriptional splicing was suppressed by CDK12 inhibition. Taken together, these studies reveal the roles of CDK12 in regulating transcription elongation, transcription termination, co-transcriptional splicing, and RNA turnover. Over 600 genes showed prematurely terminated transcription when CDK12 was inhibited CDK12 promotes transcriptional readthrough past transcription end sites (TESs) CDK12 promotes splicing and affects transcript stability
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Affiliation(s)
- Brian Magnuson
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA
- Rogel Cancer Center and Center for RNA Biomedicine, Michigan Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Karan Bedi
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA
- Rogel Cancer Center and Center for RNA Biomedicine, Michigan Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Bartlomiej Bartkowiak
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Hailey Blinkiewicz
- Department of Radiation Oncology, Michigan Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Michelle T. Paulsen
- Department of Radiation Oncology, Michigan Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Arno Greenleaf
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Mats Ljungman
- Rogel Cancer Center and Center for RNA Biomedicine, Michigan Medicine, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Radiation Oncology, Michigan Medicine, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA
- Corresponding author
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56
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Zhou S, Dong J, Xiong M, Gan S, Wen Y, Zhang J, Wang X, Yuan S, Gui Y. UHRF1 interacts with snRNAs and regulates alternative splicing in mouse spermatogonial stem cells. Stem Cell Reports 2022; 17:1859-1873. [PMID: 35905740 PMCID: PMC9391524 DOI: 10.1016/j.stemcr.2022.06.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 12/22/2022] Open
Abstract
Life-long male fertility relies on exquisite homeostasis and the development of spermatogonial stem cells (SSCs); however, the underlying molecular genetic and epigenetic regulation in this equilibrium process remains unclear. Here, we document that UHRF1 interacts with snRNAs to regulate pre-mRNA alternative splicing in SSCs and is required for the homeostasis of SSCs in mice. Genetic deficiency of UHRF1 in mouse prospermatogonia results in gradual loss of spermatogonial stem cells, eventually leading to Sertoli-cell-only syndrome (SCOS) and male infertility. Comparative RNA-seq data provide evidence that Uhrf1 ablation dysregulates previously reported SSC maintenance- and differentiation-related genes. We further found that UHRF1 could act as an alternative RNA splicing regulator and interact with Tle3 transcripts to regulate its splicing event in spermatogonia. Collectively, our data reveal a multifunctional role for UHRF1 in regulating gene expression programs and alternative splicing during SSC homeostasis, which may provide clues for treating human male infertility.
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Affiliation(s)
- Shumin Zhou
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Juan Dong
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Mengneng Xiong
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shiming Gan
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yujiao Wen
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jin Zhang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xiaoli Wang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shuiqiao Yuan
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Laboratory Animal Center, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China; Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, Guangdong 518057, China.
| | - Yaoting Gui
- Guangdong Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen PKU-HKUST Medical Center, Shenzhen, Guangdong 518036, China.
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57
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Ron M, Ulitsky I. Context-specific effects of sequence elements on subcellular localization of linear and circular RNAs. Nat Commun 2022; 13:2481. [PMID: 35513423 PMCID: PMC9072321 DOI: 10.1038/s41467-022-30183-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 04/05/2022] [Indexed: 12/24/2022] Open
Abstract
Long RNAs vary extensively in their post-transcriptional fates, and this variation is attributed in part to short sequence elements. We used massively parallel RNA assays to study how sequences derived from noncoding RNAs influence the subcellular localization and stability of circular and linear RNAs, including spliced and unspliced forms. We find that the effects of sequence elements strongly depend on the host RNA context, with limited overlap between sequences that drive nuclear enrichment of linear and circular RNAs. Binding of specific RNA binding proteins underpins some of these differences-SRSF1 binding leads to nuclear enrichment of circular RNAs; SAFB binding is associated with nuclear enrichment of predominantly unspliced linear RNAs; and IGF2BP1 promotes export of linear spliced RNA molecules. The post-transcriptional fate of long RNAs is thus dictated by combinatorial contributions of specific sequence elements, of splicing, and of the presence of the terminal features unique to linear RNAs.
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Affiliation(s)
- Maya Ron
- Departments of Biological Regulation and Molecular Neuroscience, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Igor Ulitsky
- Departments of Biological Regulation and Molecular Neuroscience, Weizmann Institute of Science, Rehovot, 76100, Israel.
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58
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Co-transcriptional splicing efficiency is a gene-specific feature that can be regulated by TGFβ. Commun Biol 2022; 5:277. [PMID: 35347226 PMCID: PMC8960766 DOI: 10.1038/s42003-022-03224-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 03/03/2022] [Indexed: 11/26/2022] Open
Abstract
Differential splicing efficiency of specific introns is a mechanism that dramatically increases protein diversity, based on selection of alternative exons for the final mature mRNA. However, it is unclear whether splicing efficiency of introns within the same gene is coordinated and eventually regulated as a mechanism to control mature mRNA levels. Based on nascent chromatin-associated RNA-sequencing data, we now find that co-transcriptional splicing (CTS) efficiency tends to be similar between the different introns of a gene. We establish that two well-differentiated strategies for CTS efficiency exist, at the extremes of a gradient: short genes that produce high levels of pre-mRNA undergo inefficient splicing, while long genes with relatively low levels of pre-mRNA have an efficient splicing. Notably, we observe that genes with efficient CTS display a higher level of mature mRNA relative to their pre-mRNA levels. Further, we show that the TGFβ signal transduction pathway regulates the general CTS efficiency, causing changes in mature mRNA levels. Taken together, our data indicate that CTS efficiency is a gene-specific characteristic that can be regulated to control gene expression. Co-transcriptional splicing efficiency is a gene-specific characteristic that can be regulated by TGFβ to modulate gene expression.
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59
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Pitolli C, Marini A, Sette C, Pagliarini V. Non-Canonical Splicing and Its Implications in Brain Physiology and Cancer. Int J Mol Sci 2022; 23:ijms23052811. [PMID: 35269953 PMCID: PMC8911335 DOI: 10.3390/ijms23052811] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 02/01/2023] Open
Abstract
The advance of experimental and computational techniques has allowed us to highlight the existence of numerous different mechanisms of RNA maturation, which have been so far unknown. Besides canonical splicing, consisting of the removal of introns from pre-mRNA molecules, non-canonical splicing events may occur to further increase the regulatory and coding potential of the human genome. Among these, splicing of microexons, recursive splicing and biogenesis of circular and chimeric RNAs through back-splicing and trans-splicing processes, respectively, all contribute to expanding the repertoire of RNA transcripts with newly acquired regulatory functions. Interestingly, these non-canonical splicing events seem to occur more frequently in the central nervous system, affecting neuronal development and differentiation programs with important implications on brain physiology. Coherently, dysregulation of non-canonical RNA processing events is associated with brain disorders, including brain tumours. Herein, we summarize the current knowledge on molecular and regulatory mechanisms underlying canonical and non-canonical splicing events with particular emphasis on cis-acting elements and trans-acting factors that all together orchestrate splicing catalysis reactions and decisions. Lastly, we review the impact of non-canonical splicing on brain physiology and pathology and how unconventional splicing mechanisms may be targeted or exploited for novel therapeutic strategies in cancer.
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Affiliation(s)
- Consuelo Pitolli
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (C.P.); (C.S.)
- GSTEP-Organoids Research Core Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy;
| | - Alberto Marini
- GSTEP-Organoids Research Core Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy;
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (C.P.); (C.S.)
- GSTEP-Organoids Research Core Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy;
| | - Vittoria Pagliarini
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (C.P.); (C.S.)
- GSTEP-Organoids Research Core Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy;
- Correspondence:
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60
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Gañez-Zapater A, Mackowiak SD, Guo Y, Tarbier M, Jordán-Pla A, Friedländer MR, Visa N, Östlund Farrants AK. The SWI/SNF subunit BRG1 affects alternative splicing by changing RNA binding factor interactions with nascent RNA. Mol Genet Genomics 2022; 297:463-484. [PMID: 35187582 PMCID: PMC8960663 DOI: 10.1007/s00438-022-01863-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 01/23/2022] [Indexed: 11/29/2022]
Abstract
BRG1 and BRM are ATPase core subunits of the human SWI/SNF chromatin remodelling complexes mainly associated with transcriptional initiation. They also have a role in alternative splicing, which has been shown for BRM-containing SWI/SNF complexes at a few genes. Here, we have identified a subset of genes which harbour alternative exons that are affected by SWI/SNF ATPases by expressing the ATPases BRG1 and BRM in C33A cells, a BRG1- and BRM-deficient cell line, and analysed the effect on splicing by RNA sequencing. BRG1- and BRM-affected sub-sets of genes favouring both exon inclusion and exon skipping, with only a minor overlap between the ATPase. Some of the changes in alternative splicing induced by BRG1 and BRM expression did not require the ATPase activity. The BRG1-ATPase independent included exons displayed an exon signature of a high GC content. By investigating three genes with exons affected by the BRG-ATPase-deficient variant, we show that these exons accumulated phosphorylated RNA pol II CTD, both serine 2 and serine 5 phosphorylation, without an enrichment of the RNA polymerase II. The ATPases were recruited to the alternative exons, together with both core and signature subunits of SWI/SNF complexes, and promoted the binding of RNA binding factors to chromatin and RNA at the alternative exons. The interaction with the nascent RNP, however, did not reflect the association to chromatin. The hnRNPL, hnRNPU and SAM68 proteins associated with chromatin in cells expressing BRG1 and BRM wild type, but the binding of hnRNPU to the nascent RNP was excluded. This suggests that SWI/SNF can regulate alternative splicing by interacting with splicing-RNA binding factor and influence their binding to the nascent pre-mRNA particle.
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Affiliation(s)
- Antoni Gañez-Zapater
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, The Arrhenius Laboratories F4, 106 91, Stockholm, Sweden
- Center for Genomic Regulation, 08003, Barcelona, Spain
| | - Sebastian D Mackowiak
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91, Stockholm, Sweden
- Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195, Berlin, Germany
| | - Yuan Guo
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, The Arrhenius Laboratories F4, 106 91, Stockholm, Sweden
| | - Marcel Tarbier
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91, Stockholm, Sweden
| | - Antonio Jordán-Pla
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, The Arrhenius Laboratories F4, 106 91, Stockholm, Sweden
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencies Biológicas, Valencia University, C/Dr. Moliner, 50, 46100, Burjassot, Spain
| | - Marc R Friedländer
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91, Stockholm, Sweden
| | - Neus Visa
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, The Arrhenius Laboratories F4, 106 91, Stockholm, Sweden
| | - Ann-Kristin Östlund Farrants
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, The Arrhenius Laboratories F4, 106 91, Stockholm, Sweden.
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61
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Christopher JA, Geladaki A, Dawson CS, Vennard OL, Lilley KS. Subcellular Transcriptomics and Proteomics: A Comparative Methods Review. Mol Cell Proteomics 2022; 21:100186. [PMID: 34922010 PMCID: PMC8864473 DOI: 10.1016/j.mcpro.2021.100186] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 11/16/2021] [Accepted: 12/13/2021] [Indexed: 12/23/2022] Open
Abstract
The internal environment of cells is molecularly crowded, which requires spatial organization via subcellular compartmentalization. These compartments harbor specific conditions for molecules to perform their biological functions, such as coordination of the cell cycle, cell survival, and growth. This compartmentalization is also not static, with molecules trafficking between these subcellular neighborhoods to carry out their functions. For example, some biomolecules are multifunctional, requiring an environment with differing conditions or interacting partners, and others traffic to export such molecules. Aberrant localization of proteins or RNA species has been linked to many pathological conditions, such as neurological, cancer, and pulmonary diseases. Differential expression studies in transcriptomics and proteomics are relatively common, but the majority have overlooked the importance of subcellular information. In addition, subcellular transcriptomics and proteomics data do not always colocate because of the biochemical processes that occur during and after translation, highlighting the complementary nature of these fields. In this review, we discuss and directly compare the current methods in spatial proteomics and transcriptomics, which include sequencing- and imaging-based strategies, to give the reader an overview of the current tools available. We also discuss current limitations of these strategies as well as future developments in the field of spatial -omics.
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Affiliation(s)
- Josie A Christopher
- Department of Biochemistry, Cambridge Centre for Proteomics, University of Cambridge, Cambridge, UK; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, Cambridge, UK
| | - Aikaterini Geladaki
- Department of Biochemistry, Cambridge Centre for Proteomics, University of Cambridge, Cambridge, UK; Department of Genetics, University of Cambridge, Cambridge, UK
| | - Charlotte S Dawson
- Department of Biochemistry, Cambridge Centre for Proteomics, University of Cambridge, Cambridge, UK; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, Cambridge, UK
| | - Owen L Vennard
- Department of Biochemistry, Cambridge Centre for Proteomics, University of Cambridge, Cambridge, UK; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, Cambridge, UK
| | - Kathryn S Lilley
- Department of Biochemistry, Cambridge Centre for Proteomics, University of Cambridge, Cambridge, UK; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, Cambridge, UK.
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62
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Alternative polyadenylation by sequential activation of distal and proximal PolyA sites. Nat Struct Mol Biol 2022; 29:21-31. [PMID: 35013598 DOI: 10.1038/s41594-021-00709-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 11/29/2021] [Indexed: 02/08/2023]
Abstract
Analogous to alternative splicing, alternative polyadenylation (APA) has long been thought to occur independently at proximal and distal polyA sites. Using fractionation-seq, we unexpectedly identified several hundred APA genes in human cells whose distal polyA isoforms are retained in chromatin/nuclear matrix and whose proximal polyA isoforms are released into the cytoplasm. Global metabolic PAS-seq and Nanopore long-read RNA-sequencing provide further evidence that the strong distal polyA sites are processed first and the resulting transcripts are subsequently anchored in chromatin/nuclear matrix to serve as precursors for further processing at proximal polyA sites. Inserting an autocleavable ribozyme between the proximal and distal polyA sites, coupled with a Cleave-seq approach that we describe here, confirms that the distal polyA isoform is indeed the precursor to the proximal polyA isoform. Therefore, unlike alternative splicing, APA sites are recognized independently, and in many cases, in a sequential manner. This provides a versatile strategy to regulate gene expression in mammalian cells.
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63
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Tan JY, Marques AC. The activity of human enhancers is modulated by the splicing of their associated lncRNAs. PLoS Comput Biol 2022; 18:e1009722. [PMID: 35015755 PMCID: PMC8803168 DOI: 10.1371/journal.pcbi.1009722] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 01/31/2022] [Accepted: 12/05/2021] [Indexed: 11/19/2022] Open
Abstract
Pervasive enhancer transcription is at the origin of more than half of all long noncoding RNAs in humans. Transcription of enhancer-associated long noncoding RNAs (elncRNA) contribute to their cognate enhancer activity and gene expression regulation in cis. Recently, splicing of elncRNAs was shown to be associated with elevated enhancer activity. However, whether splicing of elncRNA transcripts is a mere consequence of accessibility at highly active enhancers or if elncRNA splicing directly impacts enhancer function, remains unanswered. We analysed genetically driven changes in elncRNA splicing, in humans, to address this outstanding question. We showed that splicing related motifs within multi-exonic elncRNAs evolved under selective constraints during human evolution, suggesting the processing of these transcripts is unlikely to have resulted from transcription across spurious splice sites. Using a genome-wide and unbiased approach, we used nucleotide variants as independent genetic factors to directly assess the causal relationship that underpin elncRNA splicing and their cognate enhancer activity. We found that the splicing of most elncRNAs is associated with changes in chromatin signatures at cognate enhancers and target mRNA expression. We provide evidence that efficient and conserved processing of enhancer-associated elncRNAs contributes to enhancer activity. Most, if not all, active enhancers are transcribed, giving rise to a plethora of transcripts, including enhancer-associated long noncoding RNAs (elncRNAs). Changes in elncRNA levels impacts cognate enhancer activity. Recently splicing of elncRNA has also been found to associate with enhancer activity. Whether this associations reflects a contribution of elncRNA splicing to increased enhancer activity or else is simply the consequence of increased chromatin accessibility that promotes transcriptional elongation and allows for spurious splicing events remains unknown. We show that natural selection has acted, at the species and population level, to preserve DNA elements required for frequent and efficient elncRNA splicing Importantly, using a genome-wide and unbiased statistical population genomics approach, we demonstrate that elncRNA splicing is associated with cognate enhancer function, contributing to chromatin status and enhancer activity. Our results provides strong evidence that efficient elncRNA splicing contributes to enhancer activity genome-wide.
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Affiliation(s)
- Jennifer Yihong Tan
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
- * E-mail: (JYT); (ACM)
| | - Ana Claudia Marques
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
- * E-mail: (JYT); (ACM)
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64
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Dai X, Li Y, Liu W, Pan X, Guo C, Zhao X, Lv J, Lei H, Zhang L. Application of RNA subcellular fraction estimation method to explore RNA localization regulation. G3 (BETHESDA, MD.) 2022; 12:jkab371. [PMID: 34791188 PMCID: PMC8727992 DOI: 10.1093/g3journal/jkab371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/18/2021] [Indexed: 12/15/2022]
Abstract
RNA localization is involved in multiple biological processes. Recent advances in subcellular fractionation-based sequencing approaches uncovered localization pattern on a global scale. Most of existing methods adopt relative localization ratios (such as ratios of separately normalized transcripts per millions of different subcellular fractions without considering the difference in total RNA abundances in different fractions), however, absolute ratios may yield different results on the preference to different cellular compartment. Experimentally, adding external Spike-in RNAs to different fractionation can be used to obtain absolute ratios. In addition, a spike-in independent computational approach based on multiple linear regression model can also be used. However, currently, no custom tool is available. To solve this problem, we developed a method called subcellular fraction abundance estimator to correctly estimate relative RNA abundances of different subcellular fractionations. The ratios estimated by our method were consistent with existing reports. By applying the estimated ratios for different fractions, we explored the RNA localization pattern in cell lines and also predicted RBP motifs that were associated with different localization patterns. In addition, we showed that different isoforms of same genes could exhibit distinct localization patterns. To conclude, we believed our tool will facilitate future subcellular fractionation-related sequencing study to explore the function of RNA localization in various biological problems.
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Affiliation(s)
- Xiaomin Dai
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yangmengjie Li
- Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian 116044, China
| | - Weizhen Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xiuqi Pan
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Chenyue Guo
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xiaojing Zhao
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jingwen Lv
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haixin Lei
- Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian 116044, China
| | - Liye Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
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65
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Xie J, Zhang X, Zheng J, Hong X, Tong X, Liu X, Xue Y, Wang X, Zhang Y, Liu S. Two novel RNA-binding proteins identification through computational prediction and experimental validation. Genomics 2021; 114:149-160. [PMID: 34921931 DOI: 10.1016/j.ygeno.2021.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 08/05/2021] [Accepted: 12/13/2021] [Indexed: 11/16/2022]
Abstract
Since RBPs play important roles in the cell, it's particularly important to find new RBPs. We performed iRIP-seq and CLIP-seq to verify two proteins, CLIP1 and DMD, predicted by RBPPred whether are RBPs or not. The experimental results confirm that these two proteins have RNA-binding activity. We identified significantly enriched binding motifs UGGGGAGG, CUUCCG and CCCGU for CLIP1 (iRIP-seq), DMD (iRIP-seq) and DMD (CLIP-seq), respectively. The computational KEGG and GO analysis show that the CLIP1 and DMD share some biological processes and functions. Besides, we found that the SNPs between DMD and its RNA partners may be associated with Becker muscular dystrophy, Duchenne muscular dystrophy, Dilated cardiomyopathy 3B and Cardiovascular phenotype. Among the thirteen cancers data, CLIP1 and another 300 oncogenes always co-occur, and 123 of these 300 genes interact with CLIP1. These cancers may be associated with the mutations occurred in both CLIP1 and the genes it interacts with.
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Affiliation(s)
- Juan Xie
- School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xiaoli Zhang
- School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Jinfang Zheng
- School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xu Hong
- School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xiaoxue Tong
- School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xudong Liu
- School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yaqiang Xue
- Laboratory for Genome Regulation and Human Health, ABLife Inc., Wuhan, Hubei 430075, China
| | - Xuelian Wang
- ABLife BioBigData Institute, Wuhan, Hubei 430075, China
| | - Yi Zhang
- ABLife BioBigData Institute, Wuhan, Hubei 430075, China
| | - Shiyong Liu
- School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
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66
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Maudlin IE, Beggs JD. Conditional depletion of transcriptional kinases Ctk1 and Bur1 and effects on co-transcriptional spliceosome assembly and pre-mRNA splicing. RNA Biol 2021; 18:782-793. [PMID: 34705599 PMCID: PMC8782173 DOI: 10.1080/15476286.2021.1991673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 09/21/2021] [Indexed: 11/28/2022] Open
Abstract
From yeast to humans, pre-mRNA splicing occurs mainly co-transcriptionally, with splicing and transcription functionally coupled such that they influence one another. The recruitment model of co-transcriptional splicing proposes that core members of the transcription elongation machinery have the potential to influence co-transcriptional spliceosome assembly and pre-mRNA splicing. Here, we tested whether the transcription elongation kinases Bur1 and Ctk1 affect co-transcriptional spliceosome assembly and pre-mRNA splicing in the budding yeast Saccharomyces cerevisiae. In S. cerevisiae, Ctk1 is the major kinase that phosphorylates serine 2 of the carboxy-terminal domain of the largest subunit of RNA polymerase II, whilst Bur1 augments the kinase activity of Ctk1 and is the major kinase for elongation factor Spt5. We used the auxin-inducible degron system to conditionally deplete Bur1 and Ctk1 kinases, and investigated the effects on co-transcriptional spliceosome assembly and pre-mRNA splicing. Depletion of Ctk1 effectively reduced phosphorylation of serine 2 of the carboxy-terminal domain but did not impact co-transcriptional spliceosome assembly or pre-mRNA splicing. In striking contrast, depletion of Bur1 did not reduce phosphorylation of serine 2 of the carboxy-terminal domain, but reduced Spt5 phosphorylation and enhanced co-transcriptional spliceosome assembly and pre-mRNA splicing, suggesting a role for this kinase in modulating co-transcriptional splicing.
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Affiliation(s)
- Isabella E. Maudlin
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Jean D. Beggs
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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67
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DiStefano JK, Gerhard GS. Long Noncoding RNAs and Human Liver Disease. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2021; 17:1-21. [PMID: 34416820 DOI: 10.1146/annurev-pathol-042320-115255] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Long noncoding RNAs (lncRNAs) are pervasively transcribed in the genome, exhibit a diverse range of biological functions, and exert effects through a variety of mechanisms. The sheer number of lncRNAs in the human genome has raised important questions about their potential biological significance and roles in human health and disease. Technological and computational advances have enabled functional annotation of a large number of lncRNAs. Though the number of publications related to lncRNAs has escalated in recent years, relatively few have focused on those involved in hepatic physiology and pathology. We provide an overview of evolving lncRNA classification systems and characteristics and highlight important advances in our understanding of the contribution of lncRNAs to liver disease, with a focus on nonalcoholic steatohepatitis, hepatocellular carcinoma, and cholestatic liver disease. Expected final online publication date for the Annual Review of Pathology: Mechanisms of Disease, Volume 17 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Johanna K DiStefano
- Diabetes and Fibrotic Disease Research Unit, Translational Genomics Research Institute, Phoenix, Arizona 85004, USA;
| | - Glenn S Gerhard
- Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA;
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68
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Chaudhary S, Jabre I, Syed NH. Epigenetic differences in an identical genetic background modulate alternative splicing in A. thaliana. Genomics 2021; 113:3476-3486. [PMID: 34391867 DOI: 10.1016/j.ygeno.2021.08.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 08/02/2021] [Accepted: 08/10/2021] [Indexed: 11/19/2022]
Abstract
How stable and temperature-dependent variations in DNA methylation and nucleosome occupancy influence alternative splicing (AS) remains poorly understood in plants. To answer this, we generated transcriptome, whole-genome bisulfite, and MNase sequencing data for an epigenetic Recombinant Inbred Line (epiRIL) of A. thaliana at normal and cold temperature. For comparative analysis, the same data sets for the parental ecotype Columbia (Col-0) were also generated, whereas for DNA methylation, previously published high confidence methylation profiles of Col-0 were used. Significant epigenetic differences in an identical genetic background were observed between Col-0 and epiRIL lines under normal and cold temperatures. Our transcriptome data revealed that differential DNA methylation and nucleosome occupancy modulate expression levels of many genes and AS in response to cold. Collectively, DNA methylation and nucleosome levels exhibit characteristic patterns around intron-exon boundaries at normal and cold conditions, and any perturbation in them, in an identical genetic background is sufficient to modulate AS in Arabidopsis.
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Affiliation(s)
- Saurabh Chaudhary
- School of Psychology and Life Sciences, Canterbury Christ Church University, Canterbury CT1 1QU, UK; Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK.
| | - Ibtissam Jabre
- School of Psychology and Life Sciences, Canterbury Christ Church University, Canterbury CT1 1QU, UK; Department of Microbial Sciences, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Naeem H Syed
- School of Psychology and Life Sciences, Canterbury Christ Church University, Canterbury CT1 1QU, UK.
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69
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Thind AS, Monga I, Thakur PK, Kumari P, Dindhoria K, Krzak M, Ranson M, Ashford B. Demystifying emerging bulk RNA-Seq applications: the application and utility of bioinformatic methodology. Brief Bioinform 2021; 22:6330938. [PMID: 34329375 DOI: 10.1093/bib/bbab259] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 06/14/2021] [Accepted: 06/18/2021] [Indexed: 12/13/2022] Open
Abstract
Significant innovations in next-generation sequencing techniques and bioinformatics tools have impacted our appreciation and understanding of RNA. Practical RNA sequencing (RNA-Seq) applications have evolved in conjunction with sequence technology and bioinformatic tools advances. In most projects, bulk RNA-Seq data is used to measure gene expression patterns, isoform expression, alternative splicing and single-nucleotide polymorphisms. However, RNA-Seq holds far more hidden biological information including details of copy number alteration, microbial contamination, transposable elements, cell type (deconvolution) and the presence of neoantigens. Recent novel and advanced bioinformatic algorithms developed the capacity to retrieve this information from bulk RNA-Seq data, thus broadening its scope. The focus of this review is to comprehend the emerging bulk RNA-Seq-based analyses, emphasizing less familiar and underused applications. In doing so, we highlight the power of bulk RNA-Seq in providing biological insights.
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Affiliation(s)
- Amarinder Singh Thind
- University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Isha Monga
- Columbia University, New York City, NY, USA
| | | | - Pallawi Kumari
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India
| | - Kiran Dindhoria
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India
| | | | - Marie Ranson
- University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Bruce Ashford
- University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
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70
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The upstream 5' splice site remains associated to the transcription machinery during intron synthesis. Nat Commun 2021; 12:4545. [PMID: 34315864 PMCID: PMC8316553 DOI: 10.1038/s41467-021-24774-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 07/02/2021] [Indexed: 12/28/2022] Open
Abstract
In the earliest step of spliceosome assembly, the two splice sites flanking an intron are brought into proximity by U1 snRNP and U2AF along with other proteins. The mechanism that facilitates this intron looping is poorly understood. Using a CRISPR interference-based approach to halt RNA polymerase II transcription in the middle of introns in human cells, we discovered that the nascent 5′ splice site base pairs with a U1 snRNA that is tethered to RNA polymerase II during intron synthesis. This association functionally corresponds with splicing outcome, involves bona fide 5′ splice sites and cryptic intronic sites, and occurs transcriptome-wide. Overall, our findings reveal that the upstream 5′ splice sites remain attached to the transcriptional machinery during intron synthesis and are thus brought into proximity of the 3′ splice sites; potentially mediating the rapid splicing of long introns. We know that most splicing reactions take place co-transcriptionally, but how the transcription machinery facilitate splicing of introns is unknown. Here the authors show that the 5′ splice site remains associated with the transcription machinery during intron synthesis through U1 snRNP, providing a basis for the rapid splicing reaction of introns.
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71
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de Melo Costa VR, Pfeuffer J, Louloupi A, Ørom UAV, Piro RM. SPLICE-q: a Python tool for genome-wide quantification of splicing efficiency. BMC Bioinformatics 2021; 22:368. [PMID: 34266387 PMCID: PMC8281633 DOI: 10.1186/s12859-021-04282-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 07/06/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Introns are generally removed from primary transcripts to form mature RNA molecules in a post-transcriptional process called splicing. An efficient splicing of primary transcripts is an essential step in gene expression and its misregulation is related to numerous human diseases. Thus, to better understand the dynamics of this process and the perturbations that might be caused by aberrant transcript processing it is important to quantify splicing efficiency. RESULTS Here, we introduce SPLICE-q, a fast and user-friendly Python tool for genome-wide SPLICing Efficiency quantification. It supports studies focusing on the implications of splicing efficiency in transcript processing dynamics. SPLICE-q uses aligned reads from strand-specific RNA-seq to quantify splicing efficiency for each intron individually and allows the user to select different levels of restrictiveness concerning the introns' overlap with other genomic elements such as exons of other genes. We applied SPLICE-q to globally assess the dynamics of intron excision in yeast and human nascent RNA-seq. We also show its application using total RNA-seq from a patient-matched prostate cancer sample. CONCLUSIONS Our analyses illustrate that SPLICE-q is suitable to detect a progressive increase of splicing efficiency throughout a time course of nascent RNA-seq and it might be useful when it comes to understanding cancer progression beyond mere gene expression levels. SPLICE-q is available at: https://github.com/vrmelo/SPLICE-q.
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Affiliation(s)
- Verônica R de Melo Costa
- Institute of Computer Science and Institute of Bioinformatics, Freie Universität Berlin, Berlin, Germany.
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany.
| | - Julianus Pfeuffer
- Institute of Computer Science and Institute of Bioinformatics, Freie Universität Berlin, Berlin, Germany
- Department of Computer Science, Eberhard Karls Universität Tübingen, Tübingen, Germany
- Institute for Bioinformatics and Medical Informatics Tübingen, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Annita Louloupi
- Max Delbrück Center for Molecular Medicine, Berlin Institute for Medical Systems Biology, Berlin, Germany
| | - Ulf A V Ørom
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Rosario M Piro
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy.
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72
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Zhu F, Zhang F, Hu L, Liu H, Li Y. Integrated Genome and Transcriptome Sequencing to Solve a Neuromuscular Puzzle: Miyoshi Muscular Dystrophy and Early Onset Primary Dystonia in Siblings of the Same Family. Front Genet 2021; 12:672906. [PMID: 34276779 PMCID: PMC8283672 DOI: 10.3389/fgene.2021.672906] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/23/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Neuromuscular disorders (NMD), many of which are hereditary, affect muscular function. Due to advances in high-throughput sequencing technologies, the diagnosis of hereditary NMDs has dramatically improved in recent years. METHODS AND RESULTS In this study, we report an family with two siblings exhibiting two different NMD, Miyoshi muscular dystrophy (MMD) and early onset primary dystonia (EOPD). Whole exome sequencing (WES) identified a novel monoallelic frameshift deletion mutation (dysferlin: c.4404delC/p.I1469Sfs∗17) in the Dysferlin gene in the index patient who suffered from MMD. This deletion was inherited from his unaffected father and was carried by his younger sister with EOPD. However, immunostaining staining revealed an absence of dysferlin expression in the proband's muscle tissue and thus suggested the presence of the second underlying mutant allele in dysferlin. Using integrated RNA sequencing (RNA-seq) and whole genome sequencing (WGS) of muscle tissue, a novel deep intronic mutation in dysferlin (dysferlin: c.5341-415A > G) was discovered in the index patient. This mutation caused aberrant mRNA splicing and inclusion of an additional pseudoexon (PE) which we termed PE48.1. This PE was inherited from his unaffected mother. PE48.1 inclusion altered the Dysferlin sequence, causing premature termination of translation. CONCLUSION Using integrated genome and transcriptome sequencing, we discovered hereditary MMD and EOPD affecting two siblings of same family. Our results added further weight to the combined use of RNA-seq and WGS as an important method for detection of deep intronic gene mutations, and suggest that integrated sequencing assays are an effective strategy for the diagnosis of hereditary NMDs.
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Affiliation(s)
- Feng Zhu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fengxiao Zhang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lizhi Hu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Haowen Liu
- Department of Neurology, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Yahua Li
- Department of Respiratory Medicine, The Third Hospital of Hebei Medical University, Shijiazhuang, China
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73
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Xu P, Zhang L, Xiao Y, Li W, Hu Z, Zhang R, Li J, Wu F, Xi Y, Zou Q, Wang Z, Guo R, Ma H, Dong S, Xiao M, Yang Z, Ren X, Wei C, Yu W. UHRF1 regulates alternative splicing by binding to splicing factors and U snRNAs. Hum Mol Genet 2021; 30:2110-2122. [PMID: 34196368 DOI: 10.1093/hmg/ddab178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/08/2021] [Accepted: 06/24/2021] [Indexed: 12/12/2022] Open
Abstract
The well-established functions of UHRF1 converge to DNA biological processes, as exemplified by DNA methylation maintenance and DNA damage repair during cell cycles. However, the potential effect of UHRF1 on RNA metabolism is largely unexplored. Here, we revealed that UHRF1 serves as a novel alternative RNA splicing regulator. The protein interactome of UHRF1 identified various splicing factors. Among them, SF3B3 could interact with UHRF1 directly and participate in UHRF1-regulated alternative splicing events. Furthermore, we interrogated the RNA interactome of UHRF1, and surprisingly, we identified U snRNAs, the canonical spliceosome component, in the UHRF1-associated RNA components. Unexpectedly, we found H3R2 methylation status determines the binding preference of U snRNA, especially U2 snRNA. The involvement of U snRNAs in UHRF1-containing complex and their binding preference to specific chromatin configuration imply a finely orchestrated mechanism at play. Our results provided the resources and pinpointed the molecular basis of UHRF1-mediated alternative RNA splicing, which will help us better our understanding of the physiological and pathological roles of UHRF1 in disease development.
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Affiliation(s)
- Peng Xu
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China
| | - Lan Zhang
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China.,State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, 510060, China
| | - Yao Xiao
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China
| | - Wei Li
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China
| | - Zhiqiang Hu
- Department of Plant & Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Rukui Zhang
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China
| | - Jin Li
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China
| | - Feizhen Wu
- Key Laboratory of Medical Epigenetics and Metabolism, Institute of Clinical Science of Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yanping Xi
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China.,Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, Shanghai, 200011, China
| | - Qingping Zou
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China
| | - Zhentian Wang
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Rui Guo
- Key Laboratory of Medical Epigenetics and Metabolism, Institute of Clinical Science of Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Honghui Ma
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, 200120, China
| | - Shihua Dong
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China
| | - Min Xiao
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China.,Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, Shanghai, 200011, China
| | - Zhicong Yang
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China
| | - Xiaoguang Ren
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China
| | - Chaochun Wei
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Wenqiang Yu
- Shanghai Public Health Clinical Centre and Department of General Surgery, Huashan Hospital, Cancer Metastasis Institute and Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 201508, China
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74
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Auboeuf D. The Physics-Biology continuum challenges darwinism: Evolution is directed by the homeostasis-dependent bidirectional relation between genome and phenotype. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 167:121-139. [PMID: 34097984 DOI: 10.1016/j.pbiomolbio.2021.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/19/2021] [Accepted: 05/31/2021] [Indexed: 10/21/2022]
Abstract
The physics-biology continuum relies on the fact that life emerged from prebiotic molecules. Here, I argue that life emerged from the coupling between nucleic acid and protein synthesis during which proteins (or proto-phenotypes) maintained the physicochemical parameter equilibria (or proto-homeostasis) in the proximity of their encoding nucleic acids (or proto-genomes). This protected the proto-genome physicochemical integrity (i.e., atomic composition) from environmental physicochemical constraints, and therefore increased the probability of reproducing the proto-genome without variation. From there, genomes evolved depending on the biological activities they generated in response to environmental fluctuations. Thus, a genome maintaining homeostasis (i.e., internal physicochemical parameter equilibria), despite and in response to environmental fluctuations, maintains its physicochemical integrity and has therefore a higher probability to be reproduced without variation. Consequently, descendants have a higher probability to share the same phenotype than their parents. Otherwise, the genome is modified during replication as a consequence of the imbalance of the internal physicochemical parameters it generates, until new mutation-deriving biological activities maintain homeostasis in offspring. In summary, evolution depends on feedforward and feedback loops between genome and phenotype, as the internal physicochemical conditions that a genome generates ─ through its derived phenotype in response to environmental fluctuations ─ in turn either guarantee its stability or direct its variation. Evolution may not be explained by the Darwinism-derived, unidirectional principle (random mutations-phenotypes-natural selection) but rather by the bidirectional relationship between genome and phenotype, in which the phenotype in interaction with the environment directs the evolution of the genome it derives from.
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Affiliation(s)
- Didier Auboeuf
- ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, Laboratory of Biology and Modelling of the Cell, 46 Allée D'Italie, Site Jacques Monod, F-69007, Lyon, France.
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75
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Tan X, Liu Y, Liu Y, Zhang T, Cong S. Dysregulation of long non-coding RNAs and their mechanisms in Huntington's disease. J Neurosci Res 2021; 99:2074-2090. [PMID: 34031910 DOI: 10.1002/jnr.24825] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 01/19/2021] [Accepted: 02/26/2021] [Indexed: 12/31/2022]
Abstract
Extensive alterations in gene regulatory networks are a typical characteristic of Huntington's disease (HD); these include alterations in protein-coding genes and poorly understood non-coding RNAs (ncRNAs), which are associated with pathology caused by mutant huntingtin. Long non-coding RNAs (lncRNAs) are an important class of ncRNAs involved in a variety of biological functions, including transcriptional regulation and post-transcriptional modification of many targets, and likely contributed to the pathogenesis of HD. While a number of changes in lncRNAs expression have been observed in HD, little is currently known about their functions. Here, we discuss their possible mechanisms and molecular functions, with a particular focus on their roles in transcriptional regulation. These findings give us a better insight into HD pathogenesis and may provide new targets for the treatment of this neurodegenerative disease.
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Affiliation(s)
- Xiaoping Tan
- Department of Neurology, Shengjing Hospital of China Medical University, Shenyang, P.R. China
| | - Yang Liu
- Department of Neurology, Shengjing Hospital of China Medical University, Shenyang, P.R. China
| | - Yan Liu
- Department of Neurology, Shengjing Hospital of China Medical University, Shenyang, P.R. China
| | - Taiming Zhang
- Department of Neurology, Shengjing Hospital of China Medical University, Shenyang, P.R. China
| | - Shuyan Cong
- Department of Neurology, Shengjing Hospital of China Medical University, Shenyang, P.R. China
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76
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Abstract
PURPOSE OF REVIEW This review aims to give an update on recent findings related to the cardiac splicing factor RNA-binding motif protein 20 (RBM20) and RBM20 cardiomyopathy, a form of dilated cardiomyopathy caused by mutations in RBM20. RECENT FINDINGS While most research on RBM20 splicing targets has focused on titin (TTN), multiple studies over the last years have shown that other splicing targets of RBM20 including Ca2+/calmodulin-dependent kinase IIδ (CAMK2D) might be critically involved in the development of RBM20 cardiomyopathy. In this regard, loss of RBM20 causes an abnormal intracellular calcium handling, which may relate to the arrhythmogenic presentation of RBM20 cardiomyopathy. In addition, RBM20 presents clinically in a highly gender-specific manner, with male patients suffering from an earlier disease onset and a more severe disease progression. Further research on RBM20, and treatment of RBM20 cardiomyopathy, will need to consider both the multitude and relative contribution of the different splicing targets and related pathways, as well as gender differences.
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77
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Bedi K, Magnuson BR, Narayanan I, Paulsen M, Wilson TE, Ljungman M. Co-transcriptional splicing efficiencies differ within genes and between cell types. RNA (NEW YORK, N.Y.) 2021; 27:rna.078662.120. [PMID: 33975916 PMCID: PMC8208053 DOI: 10.1261/rna.078662.120] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 05/05/2021] [Indexed: 06/01/2023]
Abstract
Pre-mRNA splicing is carried out by the spliceosome and involves splice site recognition, removal of introns, and ligation of exons. Components of the spliceosome have been shown to interact with the elongating RNA polymerase II (RNAPII) which is thought to allow splicing to occur concurrently with transcription. However, little is known about the regulation and efficiency of co-transcriptional splicing in human cells. In this study, we used Bru-seq and BruChase-seq to determine the co-transcriptional splicing efficiencies of 17,000 introns expressed across 6 human cell lines. We found that less than half of all introns across these 6 cell lines were co-transcriptionally spliced. Splicing efficiencies for individual introns showed variations across cell lines, suggesting that splicing may be regulated in a cell-type specific manner. Moreover, the splicing efficiency of introns varied within genes. The efficiency of co-transcriptional splicing did not correlate with gene length, intron position, splice site strengths, or the intron/neighboring exons GC content. However, we identified binding signals from multiple RNA binding proteins (RBPs) that correlated with splicing efficiency, including core spliceosomal machinery components-such as SF3B4, U2AF1 and U2AF2 showing higher binding signals in poorly spliced introns. In addition, multiple RBPs, such as BUD13, PUM1 and SND1, showed preferential binding in exons that flank introns with high splicing efficiencies. The nascent RNA splicing patterns presented here across multiple cell types add to our understanding of the complexity in RNA splicing, wherein RNA-binding proteins may play important roles in determining splicing outcomes in a cell type- and intron-specific manner.
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78
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Comparative genomics in the search for conserved long noncoding RNAs. Essays Biochem 2021; 65:741-749. [PMID: 33885137 PMCID: PMC8564735 DOI: 10.1042/ebc20200069] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/15/2021] [Accepted: 03/15/2021] [Indexed: 12/23/2022]
Abstract
Long noncoding RNAs (lncRNAs) have emerged as prominent regulators of gene expression in eukaryotes. The identification of lncRNA orthologs is essential in efforts to decipher their roles across model organisms, as homologous genes tend to have similar molecular and biological functions. The relatively high sequence plasticity of lncRNA genes compared with protein-coding genes, makes the identification of their orthologs a challenging task. This is why comparative genomics of lncRNAs requires the development of specific and, sometimes, complex approaches. Here, we briefly review current advancements and challenges associated with four levels of lncRNA conservation: genomic sequences, splicing signals, secondary structures and syntenic transcription.
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79
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Long non-coding RNAs and splicing. Essays Biochem 2021; 65:723-729. [PMID: 33835135 DOI: 10.1042/ebc20200087] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 02/05/2021] [Accepted: 03/15/2021] [Indexed: 12/25/2022]
Abstract
In this review I focus on the role of splicing in long non-coding RNA (lncRNA) life. First, I summarize differences between the splicing efficiency of protein-coding genes and lncRNAs and discuss why non-coding RNAs are spliced less efficiently. In the second half of the review, I speculate why splice sites are the most conserved sequences in lncRNAs and what additional roles could splicing play in lncRNA metabolism. I discuss the hypothesis that the splicing machinery can, besides its dominant role in intron removal and exon joining, protect cells from undesired transcripts.
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80
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Yeom KH, Pan Z, Lin CH, Lim HY, Xiao W, Xing Y, Black DL. Tracking pre-mRNA maturation across subcellular compartments identifies developmental gene regulation through intron retention and nuclear anchoring. Genome Res 2021; 31:1106-1119. [PMID: 33832989 PMCID: PMC8168582 DOI: 10.1101/gr.273904.120] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 04/01/2021] [Indexed: 12/24/2022]
Abstract
Steps of mRNA maturation are important gene regulatory events that occur in distinct cellular locations. However, transcriptomic analyses often lose information on the subcellular distribution of processed and unprocessed transcripts. We generated extensive RNA-seq data sets to track mRNA maturation across subcellular locations in mouse embryonic stem cells, neuronal progenitor cells, and postmitotic neurons. We find disparate patterns of RNA enrichment between the cytoplasmic, nucleoplasmic, and chromatin fractions, with some genes maintaining more polyadenylated RNA in chromatin than in the cytoplasm. We bioinformatically defined four regulatory groups for intron retention, including complete cotranscriptional splicing, complete intron retention in the cytoplasmic RNA, and two intron groups present in nuclear and chromatin transcripts but fully excised in cytoplasm. We found that introns switch their regulatory group between cell types, including neuronally excised introns repressed by polypyrimidine track binding protein 1 (PTBP1). Transcripts for the neuronal gamma-aminobutyric acid (GABA) B receptor, 1 (Gabbr1) are highly expressed in mESCs but are absent from the cytoplasm. Instead, incompletely spliced Gabbr1 RNA remains sequestered on chromatin, where it is bound by PTBP1, similar to certain long noncoding RNAs. Upon neuronal differentiation, Gabbr1 RNA becomes fully processed and exported for translation. Thus, splicing repression and chromatin anchoring of RNA combine to allow posttranscriptional regulation of Gabbr1 over development. For this and other genes, polyadenylated RNA abundance does not indicate functional gene expression. Our data sets provide a rich resource for analyzing many other aspects of mRNA maturation in subcellular locations and across development.
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Affiliation(s)
- Kyu-Hyeon Yeom
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Zhicheng Pan
- Bioinformatics Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, California 90095, USA.,Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Chia-Ho Lin
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Han Young Lim
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA.,Molecular Biology Interdepartmental Doctoral Program, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Wen Xiao
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Yi Xing
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Douglas L Black
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
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81
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Gehring NH, Roignant JY. Anything but Ordinary – Emerging Splicing Mechanisms in Eukaryotic Gene Regulation. Trends Genet 2021; 37:355-372. [DOI: 10.1016/j.tig.2020.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/14/2020] [Accepted: 10/19/2020] [Indexed: 12/11/2022]
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82
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Goldfarb CN, Waxman DJ. Global analysis of expression, maturation and subcellular localization of mouse liver transcriptome identifies novel sex-biased and TCPOBOP-responsive long non-coding RNAs. BMC Genomics 2021; 22:212. [PMID: 33761883 PMCID: PMC7992343 DOI: 10.1186/s12864-021-07478-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 02/24/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND While nuclear transcription and RNA processing and localization are well established for protein coding genes (PCGs), these processes are poorly understood for long non-coding (lnc)RNAs. Here, we characterize global patterns of transcript expression, maturation and localization for mouse liver RNA, including more than 15,000 lncRNAs. PolyA-selected liver RNA was isolated and sequenced from four subcellular fractions (chromatin, nucleoplasm, total nucleus, and cytoplasm), and from the chromatin-bound fraction without polyA selection. RESULTS Transcript processing, determined from normalized intronic to exonic sequence read density ratios, progressively increased for PCG transcripts in going from the chromatin-bound fraction to the nucleoplasm and then on to the cytoplasm. Transcript maturation was similar for lncRNAs in the chromatin fraction, but was significantly lower in the nucleoplasm and cytoplasm. LncRNA transcripts were 11-fold more likely to be significantly enriched in the nucleus than cytoplasm, and 100-fold more likely to be significantly chromatin-bound than nucleoplasmic. Sequencing chromatin-bound RNA greatly increased the sensitivity for detecting lowly expressed lncRNAs and enabled us to discover and localize hundreds of novel regulated liver lncRNAs, including lncRNAs showing sex-biased expression or responsiveness to TCPOBOP a xenobiotic agonist ligand of constitutive androstane receptor (Nr1i3). CONCLUSIONS Integration of our findings with prior studies and lncRNA annotations identified candidate regulatory lncRNAs for a variety of hepatic functions based on gene co-localization within topologically associating domains or transcription divergent or antisense to PCGs associated with pathways linked to hepatic physiology and disease.
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Affiliation(s)
- Christine N Goldfarb
- Department of Biology and Bioinformatics Program, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA
| | - David J Waxman
- Department of Biology and Bioinformatics Program, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA.
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83
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Abstract
The subcellular localization of RNAs correlates with their function and how they are regulated. Most protein-coding mRNAs are exported into the cytoplasm for protein synthesis, while some mRNA species, long noncoding RNAs, and some regulatory element-associated unstable transcripts tend to be retained in the nucleus, where they function as a regulatory unit and/or are regulated by nuclear surveillance pathways. While the mechanisms regulating mRNA export and localization have been well summarized, the mechanisms governing nuclear retention of RNAs, especially of noncoding RNAs, are seldomly reviewed. In this review, we summarize recent advances in the mechanistic study of RNA nuclear retention, especially for noncoding RNAs, from the angle of cis-acting elements embedded in RNA transcripts and their interaction with trans-acting factors. We also try to illustrate the general principles of RNA nuclear retention and we discuss potential areas for future investigation.
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Affiliation(s)
- Chong Tong
- Department of Cell Biology and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yafei Yin
- Department of Cell Biology and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
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84
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Saldi T, Riemondy K, Erickson B, Bentley DL. Alternative RNA structures formed during transcription depend on elongation rate and modify RNA processing. Mol Cell 2021; 81:1789-1801.e5. [PMID: 33631106 DOI: 10.1016/j.molcel.2021.01.040] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 12/24/2022]
Abstract
Most RNA processing occurs co-transcriptionally. We interrogated nascent pol II transcripts by chemical and enzymatic probing and determined how the "nascent RNA structureome" relates to splicing, A-I editing and transcription speed. RNA folding within introns and steep structural transitions at splice sites are associated with efficient co-transcriptional splicing. A slow pol II mutant elicits extensive remodeling into more folded conformations with increased A-I editing. Introns that become more structured at their 3' splice sites get co-transcriptionally excised more efficiently. Slow pol II altered folding of intronic Alu elements where cryptic splicing and intron retention are stimulated, an outcome mimicked by UV, which decelerates transcription. Slow transcription also remodeled RNA folding around alternative exons in distinct ways that predict whether skipping or inclusion is favored, even though it occurs post-transcriptionally. Hence, co-transcriptional RNA folding modulates post-transcriptional alternative splicing. In summary, the plasticity of nascent transcripts has widespread effects on RNA processing.
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Affiliation(s)
- Tassa Saldi
- RNA Bioscience Initiative, Department Biochemistry and Molecular Genetics, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA
| | - Kent Riemondy
- RNA Bioscience Initiative, Department Biochemistry and Molecular Genetics, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA
| | - Benjamin Erickson
- RNA Bioscience Initiative, Department Biochemistry and Molecular Genetics, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA
| | - David L Bentley
- RNA Bioscience Initiative, Department Biochemistry and Molecular Genetics, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA.
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85
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Wang J, Rojas P, Mao J, Mustè Sadurnì M, Garnier O, Xiao S, Higgs MR, Garcia P, Saponaro M. Persistence of RNA transcription during DNA replication delays duplication of transcription start sites until G2/M. Cell Rep 2021; 34:108759. [PMID: 33596418 PMCID: PMC7900609 DOI: 10.1016/j.celrep.2021.108759] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 11/09/2020] [Accepted: 01/26/2021] [Indexed: 12/22/2022] Open
Abstract
As transcription and replication use DNA as substrate, conflicts between transcription and replication can occur, leading to genome instability with direct consequences for human health. To determine how the two processes are coordinated throughout S phase, we characterize both processes together at high resolution. We find that transcription occurs during DNA replication, with transcription start sites (TSSs) not fully replicated along with surrounding regions and remaining under-replicated until late in the cell cycle. TSSs undergo completion of DNA replication specifically when cells enter mitosis, when RNA polymerase II is removed. Intriguingly, G2/M DNA synthesis occurs at high frequency in unperturbed cell culture, but it is not associated with increased DNA damage and is fundamentally separated from mitotic DNA synthesis. TSSs duplicated in G2/M are characterized by a series of specific features, including high levels of antisense transcription, making them difficult to duplicate during S phase.
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Affiliation(s)
- Jianming Wang
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Patricia Rojas
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Jingwen Mao
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Martina Mustè Sadurnì
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Olivia Garnier
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Songshu Xiao
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Martin R Higgs
- Lysine Methylation and DNA Damage Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Paloma Garcia
- Stem Cells and Genome Stability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Marco Saponaro
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK.
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86
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Blumberg A, Zhao Y, Huang YF, Dukler N, Rice EJ, Chivu AG, Krumholz K, Danko CG, Siepel A. Characterizing RNA stability genome-wide through combined analysis of PRO-seq and RNA-seq data. BMC Biol 2021; 19:30. [PMID: 33588838 PMCID: PMC7885420 DOI: 10.1186/s12915-021-00949-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/05/2021] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND The concentrations of distinct types of RNA in cells result from a dynamic equilibrium between RNA synthesis and decay. Despite the critical importance of RNA decay rates, current approaches for measuring them are generally labor-intensive, limited in sensitivity, and/or disruptive to normal cellular processes. Here, we introduce a simple method for estimating relative RNA half-lives that is based on two standard and widely available high-throughput assays: Precision Run-On sequencing (PRO-seq) and RNA sequencing (RNA-seq). RESULTS Our method treats PRO-seq as a measure of transcription rate and RNA-seq as a measure of RNA concentration, and estimates the rate of RNA decay required for a steady-state equilibrium. We show that this approach can be used to assay relative RNA half-lives genome-wide, with good accuracy and sensitivity for both coding and noncoding transcription units. Using a structural equation model (SEM), we test several features of transcription units, nearby DNA sequences, and nearby epigenomic marks for associations with RNA stability after controlling for their effects on transcription. We find that RNA splicing-related features are positively correlated with RNA stability, whereas features related to miRNA binding and DNA methylation are negatively correlated with RNA stability. Furthermore, we find that a measure based on U1 binding and polyadenylation sites distinguishes between unstable noncoding and stable coding transcripts but is not predictive of relative stability within the mRNA or lincRNA classes. We also identify several histone modifications that are associated with RNA stability. CONCLUSION We introduce an approach for estimating the relative half-lives of individual RNAs. Together, our estimation method and systematic analysis shed light on the pervasive impacts of RNA stability on cellular RNA concentrations.
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Affiliation(s)
- Amit Blumberg
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Yixin Zhao
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Yi-Fei Huang
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Present Address: Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA
| | - Noah Dukler
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Edward J Rice
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Alexandra G Chivu
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Katie Krumholz
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Charles G Danko
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Adam Siepel
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
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87
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Garrido-Martín D, Borsari B, Calvo M, Reverter F, Guigó R. Identification and analysis of splicing quantitative trait loci across multiple tissues in the human genome. Nat Commun 2021; 12:727. [PMID: 33526779 PMCID: PMC7851174 DOI: 10.1038/s41467-020-20578-2] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 12/02/2020] [Indexed: 12/13/2022] Open
Abstract
Alternative splicing (AS) is a fundamental step in eukaryotic mRNA biogenesis. Here, we develop an efficient and reproducible pipeline for the discovery of genetic variants that affect AS (splicing QTLs, sQTLs). We use it to analyze the GTEx dataset, generating a comprehensive catalog of sQTLs in the human genome. Downstream analysis of this catalog provides insight into the mechanisms underlying splicing regulation. We report that a core set of sQTLs is shared across multiple tissues. sQTLs often target the global splicing pattern of genes, rather than individual splicing events. Many also affect the expression of the same or other genes, uncovering regulatory loci that act through different mechanisms. sQTLs tend to be located in post-transcriptionally spliced introns, which would function as hotspots for splicing regulation. While many variants affect splicing patterns by altering the sequence of splice sites, many more modify the binding sites of RNA-binding proteins. Genetic variants affecting splicing can have a stronger phenotypic impact than those affecting gene expression.
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Affiliation(s)
- Diego Garrido-Martín
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, 08003, Catalonia, Spain.
| | - Beatrice Borsari
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, 08003, Catalonia, Spain
| | - Miquel Calvo
- Section of Statistics, Faculty of Biology, Universitat de Barcelona (UB), Av. Diagonal 643, Barcelona, 08028, Spain
| | - Ferran Reverter
- Section of Statistics, Faculty of Biology, Universitat de Barcelona (UB), Av. Diagonal 643, Barcelona, 08028, Spain
| | - Roderic Guigó
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, 08003, Catalonia, Spain.
- Universitat Pompeu Fabra (UPF), Barcelona, Catalonia, Spain.
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88
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Jabre I, Chaudhary S, Guo W, Kalyna M, Reddy ASN, Chen W, Zhang R, Wilson C, Syed NH. Differential nucleosome occupancy modulates alternative splicing in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2021; 229:1937-1945. [PMID: 33135169 DOI: 10.1111/nph.17062] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 10/24/2020] [Indexed: 05/13/2023]
Abstract
Alternative splicing (AS) is a major gene regulatory mechanism in plants. Recent evidence supports co-transcriptional splicing in plants, hence the chromatin state can impact AS. However, how dynamic changes in the chromatin state such as nucleosome occupancy influence the cold-induced AS remains poorly understood. Here, we generated transcriptome (RNA-Seq) and nucleosome positioning (MNase-Seq) data for Arabidopsis thaliana to understand how nucleosome positioning modulates cold-induced AS. Our results show that characteristic nucleosome occupancy levels are strongly associated with the type and abundance of various AS events under normal and cold temperature conditions in Arabidopsis. Intriguingly, exitrons, alternatively spliced internal regions of protein-coding exons, exhibit distinctive nucleosome positioning pattern compared to other alternatively spliced regions. Likewise, nucleosome patterns differ between exitrons and retained introns, pointing to their distinct regulation. Collectively, our data show that characteristic changes in nucleosome positioning modulate AS in plants in response to cold.
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Affiliation(s)
- Ibtissam Jabre
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, UK
- School of Biosciences and Medicine, University of Surrey, Guildford, GU2 7XH, UK
| | - Saurabh Chaudhary
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, UK
- Cardiff School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK
| | - Wenbin Guo
- Computational Sciences, The James Hutton Institute, Dundee, DD2 5DA, UK
| | - Maria Kalyna
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences - BOKU, Muthgasse 18, 1190, Vienna, Austria
| | - Anireddy S N Reddy
- Department of Biology and Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, 80523-1878, USA
| | - Weizhong Chen
- Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY, 14853-2703, USA
| | - Runxuan Zhang
- Computational Sciences, The James Hutton Institute, Dundee, DD2 5DA, UK
| | - Cornelia 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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89
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Bridges MC, Daulagala AC, Kourtidis A. LNCcation: lncRNA localization and function. J Cell Biol 2021; 220:e202009045. [PMID: 33464299 PMCID: PMC7816648 DOI: 10.1083/jcb.202009045] [Citation(s) in RCA: 923] [Impact Index Per Article: 230.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/20/2020] [Accepted: 12/23/2020] [Indexed: 12/13/2022] Open
Abstract
Subcellular localization of RNAs has gained attention in recent years as a prevalent phenomenon that influences numerous cellular processes. This is also evident for the large and relatively novel class of long noncoding RNAs (lncRNAs). Because lncRNAs are defined as RNA transcripts >200 nucleotides that do not encode protein, they are themselves the functional units, making their subcellular localization critical to their function. The discovery of tens of thousands of lncRNAs and the cumulative evidence involving them in almost every cellular activity render assessment of their subcellular localization essential to fully understanding their biology. In this review, we summarize current knowledge of lncRNA subcellular localization, factors controlling their localization, emerging themes, including the role of lncRNA isoforms and the involvement of lncRNAs in phase separation bodies, and the implications of lncRNA localization on their function and on cellular behavior. We also discuss gaps in the current knowledge as well as opportunities that these provide for novel avenues of investigation.
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Affiliation(s)
| | | | - Antonis Kourtidis
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC
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90
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Mertes C, Scheller IF, Yépez VA, Çelik MH, Liang Y, Kremer LS, Gusic M, Prokisch H, Gagneur J. Detection of aberrant splicing events in RNA-seq data using FRASER. Nat Commun 2021; 12:529. [PMID: 33483494 PMCID: PMC7822922 DOI: 10.1038/s41467-020-20573-7] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 12/07/2020] [Indexed: 12/28/2022] Open
Abstract
Aberrant splicing is a major cause of rare diseases. However, its prediction from genome sequence alone remains in most cases inconclusive. Recently, RNA sequencing has proven to be an effective complementary avenue to detect aberrant splicing. Here, we develop FRASER, an algorithm to detect aberrant splicing from RNA sequencing data. Unlike existing methods, FRASER captures not only alternative splicing but also intron retention events. This typically doubles the number of detected aberrant events and identified a pathogenic intron retention in MCOLN1 causing mucolipidosis. FRASER automatically controls for latent confounders, which are widespread and affect sensitivity substantially. Moreover, FRASER is based on a count distribution and multiple testing correction, thus reducing the number of calls by two orders of magnitude over commonly applied z score cutoffs, with a minor loss of sensitivity. Applying FRASER to rare disease diagnostics is demonstrated by reprioritizing a pathogenic aberrant exon truncation in TAZ from a published dataset. FRASER is easy to use and freely available.
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Affiliation(s)
- Christian Mertes
- Department of Informatics, Technical University of Munich, Garching, Germany
| | - Ines F Scheller
- Department of Informatics, Technical University of Munich, Garching, Germany
- Institute of Computational Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Vicente A Yépez
- Department of Informatics, Technical University of Munich, Garching, Germany
- Quantitative Biosciences Munich, Gene Center, Ludwig-Maximilians Universität München, Munich, Germany
| | - Muhammed H Çelik
- Department of Informatics, Technical University of Munich, Garching, Germany
| | - Yingjiqiong Liang
- Department of Informatics, Technical University of Munich, Garching, Germany
| | - Laura S Kremer
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Mirjana Gusic
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Holger Prokisch
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Julien Gagneur
- Department of Informatics, Technical University of Munich, Garching, Germany.
- Institute of Computational Biology, Helmholtz Zentrum München, Neuherberg, Germany.
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.
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91
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CircNet: an encoder–decoder-based convolution neural network (CNN) for circular RNA identification. Neural Comput Appl 2021. [DOI: 10.1007/s00521-020-05673-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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92
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Liu Y, Liu X, Lin C, Jia X, Zhu H, Song J, Zhang Y. Noncoding RNAs regulate alternative splicing in Cancer. J Exp Clin Cancer Res 2021; 40:11. [PMID: 33407694 PMCID: PMC7789004 DOI: 10.1186/s13046-020-01798-2] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/03/2020] [Indexed: 12/14/2022] Open
Abstract
AS (alternative splicing) is a fundamental process by which a gene can generate multiple distinct mRNA transcripts to increase protein diversity. Defects in AS influence the occurrence and development of many diseases, including cancers, and are frequently found to participate in various aspects of cancer biology, such as promoting invasion, metastasis, apoptosis resistance and drug resistance. NcRNAs (noncoding RNAs) are an abundant class of RNAs that do not encode proteins. NcRNAs include miRNAs (microRNAs), lncRNAs (long noncoding RNAs), circRNAs (circular RNAs) and snRNAs (small nuclear RNAs) and have been proven to act as regulatory molecules that mediate cancer processes through AS. NcRNAs can directly or indirectly influence a plethora of molecular targets to regulate cis-acting elements, trans-acting factors, or pre-mRNA transcription at multiple levels, affecting the AS process and generating alternatively spliced isoforms. Consequently, ncRNA-mediated AS outcomes affect multiple cellular signaling pathways that promote or suppress cancer progression. In this review, we summarize the current mechanisms by which ncRNAs regulate AS in cancers and discuss their potential clinical applications as biomarkers and therapeutic targets.
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Affiliation(s)
- Yunze Liu
- Department of General Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China
- Department of Traditional Chinese Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China
| | - Xin Liu
- Department of Endocrinology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China
| | - Changwei Lin
- Department of Gastrointestinal Surgery, the Third XiangYa Hospital of Central South University, Changsha, 410013, China
| | - Xianhong Jia
- Department of Traditional Chinese Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China
| | - Hongmei Zhu
- Department of Traditional Chinese Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China
| | - Jun Song
- Department of General Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China.
| | - Yi Zhang
- Department of General Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221000, China.
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93
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Dhaliwal NK, Mitchell JA. Nuclear RNA Isolation and Sequencing. Methods Mol Biol 2021; 2372:75-83. [PMID: 34417744 DOI: 10.1007/978-1-0716-1697-0_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Most transcriptome studies involve sequencing and quantification of steady-state mRNA by isolating and sequencing poly (A) RNA. Although this type of sequencing data is informative to determine steady-state mRNA levels, it does not provide information on transcriptional output and thus may not always reflect changes in transcriptional regulation of gene expression . Furthermore, sequencing poly (A) RNA may miss transcribed regions of the genome not usually modified by polyadenylation which includes many long non-coding RNAs including enhancer RNA (eRNA). Here, we describe nuclear RNA sequencing (nucRNA-seq) which investigates the transcriptional landscape through sequencing and quantification of nuclear RNAs which are both unspliced and spliced transcripts for protein-coding genes and nuclear-retained long non-coding RNAs.
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Affiliation(s)
- Navroop K Dhaliwal
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Jennifer A Mitchell
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada.
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94
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Schneider-Poetsch T, Chhipi-Shrestha JK, Yoshida M. Splicing modulators: on the way from nature to clinic. J Antibiot (Tokyo) 2021; 74:603-616. [PMID: 34345042 PMCID: PMC8472923 DOI: 10.1038/s41429-021-00450-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 02/06/2023]
Abstract
Over the course of more than two decades, natural products isolated from various microorganisms and plants have built the foundation for chemical biology research into the mechanism of pre-mRNA splicing. Hand in hand with advances in scientific methodology small molecule splicing modulators have become powerful tools for investigating, not just the splicing mechanism, but also the cellular effect of altered mRNA processing. Based on thorough structure-activity studies, synthetic analogues have moved on from scientific tool compounds to experimental drugs. With current advances in drug discovery methodology and new means of attacking targets previously thought undruggable, we can expect further advances in both research and therapeutics based on small molecule splicing modulators.
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Affiliation(s)
- Tilman Schneider-Poetsch
- grid.509461.fChemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, Wako, Saitama Japan
| | | | - Minoru Yoshida
- grid.509461.fChemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, Wako, Saitama Japan ,grid.26999.3d0000 0001 2151 536XDepartment of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo Japan ,grid.26999.3d0000 0001 2151 536XCollaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo Japan
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95
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Price AJ, Jaffe AE, Weinberger DR. Cortical cellular diversity and development in schizophrenia. Mol Psychiatry 2021; 26:203-217. [PMID: 32404946 PMCID: PMC7666011 DOI: 10.1038/s41380-020-0775-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 04/23/2020] [Accepted: 04/30/2020] [Indexed: 12/31/2022]
Abstract
While a definitive understanding of schizophrenia etiology is far from current reality, an increasing body of evidence implicates perturbations in early development that alter the trajectory of brain maturation in this disorder, leading to abnormal function in early childhood and adulthood. This atypical development likely arises from an interaction of many brain cell types that follow distinct developmental paths. Because both cellular identity and development are governed by the transcriptome and epigenome, two levels of gene regulation that have the potential to reflect both genetic and environmental influences, mapping "omic" changes over development in diverse cells is a fruitful avenue for schizophrenia research. In this review, we provide a survey of human brain cellular composition and development, levels of genomic regulation that determine cellular identity and developmental trajectories, and what is known about how genomic regulation is dysregulated in specific cell types in schizophrenia. We also outline technical challenges and solutions to conducting cell type-specific functional genomic studies in human postmortem brain.
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Affiliation(s)
- Amanda J. Price
- Lieber Institute for Brain Development, Baltimore, MD,McKusick Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD
| | - Andrew E. Jaffe
- Lieber Institute for Brain Development, Baltimore, MD,McKusick Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD,Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD,Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD,Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD,Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Daniel R. Weinberger
- Lieber Institute for Brain Development, Baltimore, MD,McKusick Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD,Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD,Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD,Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD
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96
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Li M. Calculating the most likely intron splicing orders in S. pombe, fruit fly, Arabidopsis thaliana, and humans. BMC Bioinformatics 2020; 21:478. [PMID: 33099301 PMCID: PMC7585206 DOI: 10.1186/s12859-020-03818-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 10/15/2020] [Indexed: 12/01/2022] Open
Abstract
Background Introns have been shown to be spliced in a defined order, and this order influences both alternative splicing regulation and splicing fidelity, but previous studies have only considered neighbouring introns. The detailed intron splicing order remains unknown.
Results In this work, a method was developed that can calculate the intron splicing orders of all introns in each transcript. A simulation study showed that this method can accurately calculate intron splicing orders. I further applied this method to real S. pombe, fruit fly, Arabidopsis thaliana, and human sequencing datasets and found that intron splicing orders change from gene to gene and that humans contain more not in-order spliced transcripts than S. pombe, fruit fly and Arabidopsis thaliana. In addition, I reconfirmed that the first introns in humans are spliced slower than those in S. pombe, fruit fly, and Arabidopsis thaliana genome-widely. Both the calculated most likely orders and the method developed here are available on the web. Conclusions A novel computational method was developed to calculate the intron splicing orders and applied the method to real sequencing datasets. I obtained intron splicing orders for hundreds or thousands of genes in four organisms. I found humans contain more number of not in-order spliced transcripts.
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97
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Reimer K, Neugebauer K. Preparation of Mammalian Nascent RNA for Long Read Sequencing. CURRENT PROTOCOLS IN MOLECULAR BIOLOGY 2020; 133:e128. [PMID: 33085989 PMCID: PMC7586757 DOI: 10.1002/cpmb.128] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Long read sequencing technologies now allow high-quality sequencing of RNAs (or their cDNAs) that are hundreds to thousands of nucleotides long. Long read sequences of nascent RNA provide single-nucleotide-resolution information about co-transcriptional RNA processing events-e.g., splicing, folding, and base modifications. Here, we describe how to isolate nascent RNA from mammalian cells through subcellular fractionation of chromatin-associated RNA, as well as how to deplete poly(A)+ RNA and rRNA, and, finally, how to generate a full-length cDNA library for use on long read sequencing platforms. This approach allows for an understanding of coordinated splicing status across multi-intron transcripts by revealing patterns of splicing or other RNA processing events that cannot be gained from traditional short read RNA sequencing. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Subcellular fractionation Basic Protocol 2: Nascent RNA isolation and adapter ligation Basic Protocol 3: cDNA amplicon preparation.
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Affiliation(s)
- Kirsten Reimer
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar Street, New Haven CT, 06520, 203-785-2358
| | - Karla Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar Street, New Haven CT, 06520, 203-785-2358
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98
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Palazzo AF, Kang YM. GC-content biases in protein-coding genes act as an "mRNA identity" feature for nuclear export. Bioessays 2020; 43:e2000197. [PMID: 33165929 DOI: 10.1002/bies.202000197] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/30/2020] [Accepted: 10/01/2020] [Indexed: 01/11/2023]
Abstract
It has long been observed that human protein-coding genes have a particular distribution of GC-content: the 5' end of these genes has high GC-content while the 3' end has low GC-content. In 2012, it was proposed that this pattern of GC-content could act as an mRNA identity feature that would lead to it being better recognized by the cellular machinery to promote its nuclear export. In contrast, junk RNA, which largely lacks this feature, would be retained in the nucleus and targeted for decay. Now two recent papers have provided evidence that GC-content does promote the nuclear export of many mRNAs in human cells.
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Affiliation(s)
- Alexander F Palazzo
- Department of Biochemistry, University of Toronto, Toronto, ON, M5G 1M1, Canada
| | - Yoon Mo Kang
- Department of Biochemistry, University of Toronto, Toronto, ON, M5G 1M1, Canada
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99
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Yan P, Lu JY, Niu J, Gao J, Zhang MQ, Yin Y, Shen X. LncRNA Platr22 promotes super-enhancer activity and stem cell pluripotency. J Mol Cell Biol 2020; 13:295-313. [PMID: 33049031 PMCID: PMC8339366 DOI: 10.1093/jmcb/mjaa056] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 08/17/2020] [Accepted: 09/14/2020] [Indexed: 12/13/2022] Open
Abstract
Super-enhancers (SEs) comprise large clusters of enhancers, which are co-occupied by multiple lineage-specific and master transcription factors, and play pivotal roles in regulating gene expression and cell fate determination. However, it is still largely unknown whether and how SEs are regulated by the noncoding portion of the genome. Here, through genome-wide analysis, we found that long noncoding RNA (lncRNA) genes preferentially lie next to SEs. In mouse embryonic stem cells (mESCs), depletion of SE-associated lncRNA transcripts dysregulated the activity of their nearby SEs. Specifically, we revealed a critical regulatory role of the lncRNA gene Platr22 in modulating the activity of a nearby SE and the expression of the nearby pluripotency regulator ZFP281. Through these regulatory events, Platr22 contributes to pluripotency maintenance and proper differentiation of mESCs. Mechanistically, Platr22 transcripts coat chromatin near the SE region and interact with DDX5 and hnRNP-L. DDX5 further recruits p300 and other factors related to active transcription. We propose that these factors assemble into a transcription hub, thus promoting an open and active epigenetic chromatin state. Our study highlights an unanticipated role for a class of lncRNAs in epigenetically controlling the activity and vulnerability to perturbation of nearby SEs for cell fate determination.
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Affiliation(s)
- Pixi Yan
- 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
| | - Jing Niu
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China
| | - Juntao Gao
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China
| | - Michael Q Zhang
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, China
| | - Yafei Yin
- Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, 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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100
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Xu B, Meng Y, Jin Y. RNA structures in alternative splicing and back-splicing. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1626. [PMID: 32929887 DOI: 10.1002/wrna.1626] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/14/2020] [Accepted: 08/22/2020] [Indexed: 12/12/2022]
Abstract
Alternative splicing greatly expands the transcriptomic and proteomic diversities related to physiological and developmental processes in higher eukaryotes. Splicing of long noncoding RNAs, and back- and trans- splicing further expanded the regulatory repertoire of alternative splicing. RNA structures were shown to play an important role in regulating alternative splicing and back-splicing. Application of novel sequencing technologies made it possible to identify genome-wide RNA structures and interaction networks, which might provide new insights into RNA splicing regulation in vitro to in vivo. The emerging transcription-folding-splicing paradigm is changing our understanding of RNA alternative splicing regulation. Here, we review the insights into the roles and mechanisms of RNA structures in alternative splicing and back-splicing, as well as how disruption of these structures affects alternative splicing and then leads to human diseases. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, China
| | - Yijun Meng
- College of Life and Environmental Sciences, Hangzhou Normal University, Zhejiang, Hangzhou, China
| | - Yongfeng Jin
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, China
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