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Role of promoters in regulating alternative splicing. Gene 2021; 782:145523. [PMID: 33667606 DOI: 10.1016/j.gene.2021.145523] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 12/31/2020] [Accepted: 02/09/2021] [Indexed: 01/19/2023]
Abstract
Alternative splicing (AS) plays a critical role in enhancing proteome complexity in higher eukaryotes. Almost all the multi intron-containing genes undergo AS in humans. Splicing mainly occurs co-transcriptionally, where RNA polymerase II (RNA pol II) plays a crucial role in coordinating transcription and pre-mRNA splicing. Aberrant AS leads to non-functional proteins causative in various pathophysiological conditions such as cancers, neurodegenerative diseases, and muscular dystrophies. Transcription and pre-mRNA splicing are deeply interconnected and can influence each other's functions. Several studies evinced that specific promoters employed by RNA pol II dictate the RNA processing decisions. Promoter-specific recruitment of certain transcriptional factors or transcriptional coactivators influences splicing, and the extent to which these factors affect splicing has not been discussed in detail. Here, in this review, various DNA-binding proteins and their influence on promoter-specific AS are extensively discussed. Besides, this review highlights how the promoter-specific epigenetic changes might regulate AS.
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Androgen receptor and its splice variant, AR-V7, differentially induce mRNA splicing in prostate cancer cells. Sci Rep 2021; 11:1393. [PMID: 33446905 PMCID: PMC7809134 DOI: 10.1038/s41598-021-81164-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 12/23/2020] [Indexed: 12/20/2022] Open
Abstract
Prostate cancer (PCa) is dependent on the androgen receptor (AR). Advanced PCa is treated with an androgen deprivation therapy-based regimen; tumors develop resistance, although they typically remain AR-dependent. Expression of constitutively active AR variants lacking the ligand-binding domain including the variant AR-V7 contributes to this resistance. AR and AR-V7, as transcription factors, regulate many of the same genes, but also have unique activities. In this study, the capacity of the two AR isoforms to regulate splicing was examined. RNA-seq data from models that endogenously express AR and express AR-V7 in response to doxycycline were used. Both AR isoforms induced multiple changes in splicing and many changes were isoform-specific. Analyses of two endogenous genes, PGAP2 and TPD52, were performed to examine differential splicing. A novel exon that appears to be a novel transcription start site was preferentially induced by AR-V7 in PGAP2 although it is induced to a lesser extent by AR. The previously described AR induced promoter 2 usage that results in a novel protein derived from TPD52 (PrLZ) was not induced by AR-V7. AR, but not AR-V7, bound to a site proximal to promoter 2, and induction was found to depend on FOXA1.
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Munkley J, Maia TM, Ibarluzea N, Livermore KE, Vodak D, Ehrmann I, James K, Rajan P, Barbosa-Morais NL, Elliott DJ. Androgen-dependent alternative mRNA isoform expression in prostate cancer cells. F1000Res 2018; 7:1189. [PMID: 30271587 PMCID: PMC6143958 DOI: 10.12688/f1000research.15604.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/30/2018] [Indexed: 12/18/2022] Open
Abstract
Background: Androgen steroid hormones are key drivers of prostate cancer. Previous work has shown that androgens can drive the expression of alternative mRNA isoforms as well as transcriptional changes in prostate cancer cells. Yet to what extent androgens control alternative mRNA isoforms and how these are expressed and differentially regulated in prostate tumours is unknown. Methods: Here we have used RNA-Seq data to globally identify alternative mRNA isoform expression under androgen control in prostate cancer cells, and profiled the expression of these mRNA isoforms in clinical tissue. Results: Our data indicate androgens primarily switch mRNA isoforms through alternative promoter selection. We detected 73 androgen regulated alternative transcription events, including utilisation of 56 androgen-dependent alternative promoters, 13 androgen-regulated alternative splicing events, and selection of 4 androgen-regulated alternative 3' mRNA ends. 64 of these events are novel to this study, and 26 involve previously unannotated isoforms. We validated androgen dependent regulation of 17 alternative isoforms by quantitative PCR in an independent sample set. Some of the identified mRNA isoforms are in genes already implicated in prostate cancer (including LIG4, FDFT1 and RELAXIN), or in genes important in other cancers (e.g. NUP93 and MAT2A). Importantly, analysis of transcriptome data from 497 tumour samples in the TGCA prostate adenocarcinoma (PRAD) cohort identified 13 mRNA isoforms (including TPD52, TACC2 and NDUFV3) that are differentially regulated in localised prostate cancer relative to normal tissue, and 3 ( OSBPL1A, CLK3 and TSC22D3) which change significantly with Gleason grade and tumour stage. Conclusions: Our findings dramatically increase the number of known androgen regulated isoforms in prostate cancer, and indicate a highly complex response to androgens in prostate cancer cells that could be clinically important.
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Affiliation(s)
- Jennifer Munkley
- Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, Newcastle, NE1 3BZ, UK
| | - Teresa M. Maia
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028, Portugal
- VIB Proteomics Core, Albert Baertsoenkaai 3, Ghent, 9000, Belgium
| | - Nekane Ibarluzea
- Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, Newcastle, NE1 3BZ, UK
- Biocruces Bizkaia Health Research Institute, Cruces University Hospital, Barakaldo, 48903, Spain
- Centre for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Valencia, 46010, Spain
| | - Karen E. Livermore
- Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, Newcastle, NE1 3BZ, UK
| | - Daniel Vodak
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Ingrid Ehrmann
- Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, Newcastle, NE1 3BZ, UK
| | - Katherine James
- Interdisciplinary Computing and Complex BioSystems Research Group, Newcastle University, Newcastle upon Tyne, NE4 5TG, UK
- Life and Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Prabhakar Rajan
- Barts Cancer Institute, Queen Mary University of London, John Vane Science Centre, London, EC1M 6BQ, UK
| | - Nuno L. Barbosa-Morais
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028, Portugal
| | - David J. Elliott
- Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, Newcastle, NE1 3BZ, UK
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Rambout X, Dequiedt F, Maquat LE. Beyond Transcription: Roles of Transcription Factors in Pre-mRNA Splicing. Chem Rev 2017; 118:4339-4364. [PMID: 29251915 DOI: 10.1021/acs.chemrev.7b00470] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Whereas individual steps of protein-coding gene expression in eukaryotes can be studied in isolation in vitro, it has become clear that these steps are intimately connected within cells. Connections not only ensure quality control but also fine-tune the gene expression process, which must adapt to environmental changes while remaining robust. In this review, we systematically present proven and potential mechanisms by which sequence-specific DNA-binding transcription factors can alter gene expression beyond transcription initiation and regulate pre-mRNA splicing, and thereby mRNA isoform production, by (i) influencing transcription elongation rates, (ii) binding to pre-mRNA to recruit splicing factors, and/or (iii) blocking the association of splicing factors with pre-mRNA. We propose various mechanistic models throughout the review, in some cases without explicit supportive evidence, in hopes of providing fertile ground for future studies.
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Yarosh CA, Iacona JR, Lutz CS, Lynch KW. PSF: nuclear busy-body or nuclear facilitator? WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 6:351-67. [PMID: 25832716 PMCID: PMC4478221 DOI: 10.1002/wrna.1280] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 02/28/2015] [Accepted: 03/02/2015] [Indexed: 01/25/2023]
Abstract
PTB-associated splicing factor (PSF) is an abundant and essential nucleic acid-binding protein that participates in a wide range of gene regulatory processes and cellular response pathways. At the protein level, PSF consists of multiple domains, many of which remain poorly characterized. Although grouped in a family with the proteins p54nrb/NONO and PSPC1 based on sequence homology, PSF contains additional protein sequence not included in other family members. Consistently, PSF has also been implicated in functions not ascribed to p54nrb/NONO or PSPC1. Here, we provide a review of the cellular activities in which PSF has been implicated and what is known regarding the mechanisms by which PSF functions in each case. We propose that the complex domain arrangement of PSF allows for its diversity of function and integration of activities. Finally, we discuss recent evidence that individual activities of PSF can be regulated independently from one another through the activity of domain-specific co-factors.
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Affiliation(s)
- Christopher A Yarosh
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph R Iacona
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers Biomedical and Health Sciences-New Jersey Medical School, Newark, NJ, USA
| | - Carol S Lutz
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers Biomedical and Health Sciences-New Jersey Medical School, Newark, NJ, USA
| | - Kristen W Lynch
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
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