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Dahal S, Clayton K, Cabral T, Cheng R, Jahanshahi S, Ahmed C, Koirala A, Villasmil Ocando A, Malty R, Been T, Hernandez J, Mangos M, Shen D, Babu M, Calarco J, Chabot B, Attisano L, Houry WA, Cochrane A. On a path toward a broad-spectrum anti-viral: inhibition of HIV-1 and coronavirus replication by SR kinase inhibitor harmine. J Virol 2023; 97:e0039623. [PMID: 37706687 PMCID: PMC10617549 DOI: 10.1128/jvi.00396-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 07/14/2023] [Indexed: 09/15/2023] Open
Abstract
IMPORTANCE This study highlights the crucial role RNA processing plays in regulating viral gene expression and replication. By targeting SR kinases, we identified harmine as a potent inhibitor of HIV-1 as well as coronavirus (HCoV-229E and multiple SARS-CoV-2 variants) replication. Harmine inhibits HIV-1 protein expression and reduces accumulation of HIV-1 RNAs in both cell lines and primary CD4+ T cells. Harmine also suppresses coronavirus replication post-viral entry by preferentially reducing coronavirus sub-genomic RNA accumulation. By focusing on host factors rather than viral targets, our study offers a novel approach to combating viral infections that is effective against a range of unrelated viruses. Moreover, at doses required to inhibit virus replication, harmine had limited toxicity and minimal effect on the host transcriptome. These findings support the viability of targeting host cellular processes as a means of developing broad-spectrum anti-virals.
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Affiliation(s)
- Subha Dahal
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Kiera Clayton
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Tyler Cabral
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Ran Cheng
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Shahrzad Jahanshahi
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Choudhary Ahmed
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Amrit Koirala
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
- Dan L. Duncan Cancer Comprehensive Center, Baylor College of Medicine, Houston, Texas, USA
| | | | - Ramy Malty
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Research and Innovation Centre, Department of Biochemistry, University of Regina, Regina, Saskatchewan, Canada
| | - Terek Been
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Javier Hernandez
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Maria Mangos
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - David Shen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Mohan Babu
- Research and Innovation Centre, Department of Biochemistry, University of Regina, Regina, Saskatchewan, Canada
| | - John Calarco
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Benoit Chabot
- Department of Microbiology and Infectious Diseases, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Liliana Attisano
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Walid A. Houry
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Alan Cochrane
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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2
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Sun P, Zhang G, Xian M, Zhang G, Wen F, Hu Z, Hu J. Proteomic Analysis of Frozen-Thawed Spermatozoa with Different Levels of Freezability in Dairy Goats. Int J Mol Sci 2023; 24:15550. [PMID: 37958534 PMCID: PMC10648040 DOI: 10.3390/ijms242115550] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 11/15/2023] Open
Abstract
The results of artificial insemination (AI) are adversely affected by changes in sperm motility and function throughout the cryopreservation procedure. The proteome alterations of frozen-thawed spermatozoa with various levels of freezability in dairy goats, however, remain largely unknown. To discover differentially expressed proteins (DEPs) and their roles in dairy goat sperm with high or low freezability (HF or LF), we conducted 4D-DIA quantitative proteomics analysis, the results of which are presented in this work. Additionally, we explored the underlying processes that may lead to the variations in sperm freezing resistance. A total of 263 DEPs (Fold Change > 2.0, p-value < 0.05) were identified between the HF group and LF group in frozen-thawed dairy goat spermatozoa. In our Gene Ontology (GO) enrichment analysis, the DEPs were mostly associated with the regulation of biological processes, metabolic processes, and responses to stress and cellular component biogenesis. Our Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis also revealed that the DEPs were predominantly engaged in oxidative phosphorylation, N-Glycan biosythesis, and cysteine and methionien metabolism. A protein-protein interaction (PPI) network analysis revealed 14 potential proteins (NUDFB8, SDHC, PDIA4, HSPB1, etc.) that might influence the freezability of dairy goat sperm. These findings shed light on the processes underlying alterations in the proteome and sperm freezability, aiding further research on sperm cryopreservation.
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Affiliation(s)
| | | | | | | | | | | | - Jianhong Hu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China; (P.S.); (G.Z.); (M.X.); (G.Z.); (F.W.); (Z.H.)
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3
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Bogaert E, Garde A, Gautier T, Rooney K, Duffourd Y, LeBlanc P, van Reempts E, Tran Mau-Them F, Wentzensen IM, Au KS, Richardson K, Northrup H, Gatinois V, Geneviève D, Louie RJ, Lyons MJ, Laulund LW, Brasch-Andersen C, Maxel Juul T, El It F, Marle N, Callier P, Relator R, Haghshenas S, McConkey H, Kerkhof J, Cesario C, Novelli A, Brunetti-Pierri N, Pinelli M, Pennamen P, Naudion S, Legendre M, Courdier C, Trimouille A, Fenzy MD, Pais L, Yeung A, Nugent K, Roeder ER, Mitani T, Posey JE, Calame D, Yonath H, Rosenfeld JA, Musante L, Faletra F, Montanari F, Sartor G, Vancini A, Seri M, Besmond C, Poirier K, Hubert L, Hemelsoet D, Munnich A, Lupski JR, Philippe C, Thauvin-Robinet C, Faivre L, Sadikovic B, Govin J, Dermaut B, Vitobello A. SRSF1 haploinsufficiency is responsible for a syndromic developmental disorder associated with intellectual disability. Am J Hum Genet 2023; 110:790-808. [PMID: 37071997 PMCID: PMC10183470 DOI: 10.1016/j.ajhg.2023.03.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/23/2023] [Indexed: 04/20/2023] Open
Abstract
SRSF1 (also known as ASF/SF2) is a non-small nuclear ribonucleoprotein (non-snRNP) that belongs to the arginine/serine (R/S) domain family. It recognizes and binds to mRNA, regulating both constitutive and alternative splicing. The complete loss of this proto-oncogene in mice is embryonically lethal. Through international data sharing, we identified 17 individuals (10 females and 7 males) with a neurodevelopmental disorder (NDD) with heterozygous germline SRSF1 variants, mostly de novo, including three frameshift variants, three nonsense variants, seven missense variants, and two microdeletions within region 17q22 encompassing SRSF1. Only in one family, the de novo origin could not be established. All individuals featured a recurrent phenotype including developmental delay and intellectual disability (DD/ID), hypotonia, neurobehavioral problems, with variable skeletal (66.7%) and cardiac (46%) anomalies. To investigate the functional consequences of SRSF1 variants, we performed in silico structural modeling, developed an in vivo splicing assay in Drosophila, and carried out episignature analysis in blood-derived DNA from affected individuals. We found that all loss-of-function and 5 out of 7 missense variants were pathogenic, leading to a loss of SRSF1 splicing activity in Drosophila, correlating with a detectable and specific DNA methylation episignature. In addition, our orthogonal in silico, in vivo, and epigenetics analyses enabled the separation of clearly pathogenic missense variants from those with uncertain significance. Overall, these results indicated that haploinsufficiency of SRSF1 is responsible for a syndromic NDD with ID due to a partial loss of SRSF1-mediated splicing activity.
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Affiliation(s)
- Elke Bogaert
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium; Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, 9000 Ghent, Belgium
| | - Aurore Garde
- UMR1231 GAD, Inserm - Université de Bourgogne, Dijon, France; Centre de Référence Maladies Rares "Anomalies du Développement et Syndromes Malformatifs", Centre de Génétique, FHU-TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
| | - Thierry Gautier
- University Grenoble Alpes, Inserm U1209, CNRS UMR 5309, Institute for Advanced Biosciences (IAB), 38000 Grenoble, France
| | - Kathleen Rooney
- Department of Pathology and Laboratory Medicine, Western University, London, ON N5A 3K7, Canada; Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON N6A 5W9, Canada
| | - Yannis Duffourd
- UMR1231 GAD, Inserm - Université de Bourgogne, Dijon, France; Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
| | - Pontus LeBlanc
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium; Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, 9000 Ghent, Belgium
| | - Emma van Reempts
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium; Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, 9000 Ghent, Belgium
| | - Frederic Tran Mau-Them
- UMR1231 GAD, Inserm - Université de Bourgogne, Dijon, France; Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
| | | | - Kit Sing Au
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX, USA; Children's Memorial Hermann Hospital, Houston, TX, USA
| | - Kate Richardson
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX, USA; Children's Memorial Hermann Hospital, Houston, TX, USA
| | - Hope Northrup
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX, USA; Children's Memorial Hermann Hospital, Houston, TX, USA
| | - Vincent Gatinois
- Unité de Génétique Chromosomique, CHU Montpellier, Montpellier, France
| | - David Geneviève
- Montpellier University, Inserm U1183, Montpellier, France; Reference center for rare disease developmental anomaly malformative syndrome, Department of Medical Genetics, Montpellier Hospital, Montpellier, France
| | | | | | | | - Charlotte Brasch-Andersen
- Department of Clinical Genetics, Odense University Hospital, 5000 Odense, Denmark; Human Genetics, Department of Clinical Research, Health Faculty, University of Southern Denmark, 5000 Odense, Denmark
| | - Trine Maxel Juul
- Department of Clinical Genetics, Odense University Hospital, 5000 Odense, Denmark
| | - Fatima El It
- UMR1231 GAD, Inserm - Université de Bourgogne, Dijon, France
| | - Nathalie Marle
- Laboratoire de Génétique Chromosomique et Moléculaire, Pôle de Biologie, CHU de Dijon, Dijon, France
| | - Patrick Callier
- UMR1231 GAD, Inserm - Université de Bourgogne, Dijon, France; Laboratoire de Génétique Chromosomique et Moléculaire, Pôle de Biologie, CHU de Dijon, Dijon, France
| | - Raissa Relator
- Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON N6A 5W9, Canada
| | - Sadegheh Haghshenas
- Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON N6A 5W9, Canada
| | - Haley McConkey
- Department of Pathology and Laboratory Medicine, Western University, London, ON N5A 3K7, Canada; Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON N6A 5W9, Canada
| | - Jennifer Kerkhof
- Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON N6A 5W9, Canada
| | - Claudia Cesario
- Translational Cytogenomics Research Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Antonio Novelli
- Translational Cytogenomics Research Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Nicola Brunetti-Pierri
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy; Department of Translational Medicine, University of Naples Federico II, Naples, Italy
| | - Michele Pinelli
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy; Department of Translational Medicine, University of Naples Federico II, Naples, Italy
| | | | - Sophie Naudion
- Medical Genetics Department, CHU Bordeaux, Bordeaux, France
| | | | | | - Aurelien Trimouille
- INSERM U1211, Laboratoire MRGM, Bordeaux University, Bordeaux, France; Pathology Department, CHU Bordeaux, Bordeaux, France
| | - Martine Doco Fenzy
- Service de génétique, CHU de Reims, Reims, France; Service de génétique médicale, CHU de Nantes, Nantes, France; L'institut du thorax, INSERM, CNRS, UNIV Nantes, CHU de Nantes, Nantes, France
| | - Lynn Pais
- Broad Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Alison Yeung
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Parkville, VIC, Australia
| | - Kimberly Nugent
- Department of Pediatrics, Baylor College of Medicine, San Antonio, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Elizabeth R Roeder
- Department of Pediatrics, Baylor College of Medicine, San Antonio, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Tadahiro Mitani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Daniel Calame
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Hagith Yonath
- Internal Medicine A, Danek Gertner Institute of Human Genetics, Sheba Medical Center, Ramat Gan, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Baylor Genetics Laboratories, Houston, TX, USA
| | - Luciana Musante
- Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Trieste, Italy
| | - Flavio Faletra
- Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Trieste, Italy
| | - Francesca Montanari
- UO Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Giovanna Sartor
- UO Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | | | - Marco Seri
- UO Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy; Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Claude Besmond
- Université Paris Cité, Imagine Institute, INSERM UMR1163, Paris 75015, France
| | - Karine Poirier
- Université Paris Cité, Imagine Institute, INSERM UMR1163, Paris 75015, France
| | - Laurence Hubert
- Université Paris Cité, Imagine Institute, INSERM UMR1163, Paris 75015, France
| | - Dimitri Hemelsoet
- Department of Neurology, Ghent University Hospital, 9000 Ghent, Belgium
| | - Arnold Munnich
- Université Paris Cité, Imagine Institute, INSERM UMR1163, Paris 75015, France
| | - James R Lupski
- Department of Pediatrics, Baylor College of Medicine, San Antonio, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Christophe Philippe
- UMR1231 GAD, Inserm - Université de Bourgogne, Dijon, France; Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
| | - Christel Thauvin-Robinet
- UMR1231 GAD, Inserm - Université de Bourgogne, Dijon, France; Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France; Centre de Référence Maladies Rares « Déficiences intellectuelles de causes rares », Centre de Génétique, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Laurence Faivre
- UMR1231 GAD, Inserm - Université de Bourgogne, Dijon, France; Centre de Référence Maladies Rares "Anomalies du Développement et Syndromes Malformatifs", Centre de Génétique, FHU-TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
| | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, London, ON N5A 3K7, Canada; Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON N6A 5W9, Canada
| | - Jérôme Govin
- University Grenoble Alpes, Inserm U1209, CNRS UMR 5309, Institute for Advanced Biosciences (IAB), 38000 Grenoble, France
| | - Bart Dermaut
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium; Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, 9000 Ghent, Belgium.
| | - Antonio Vitobello
- UMR1231 GAD, Inserm - Université de Bourgogne, Dijon, France; Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France.
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4
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Castelli LM, Lin YH, Sanchez-Martinez A, Gül A, Mohd Imran K, Higginbottom A, Upadhyay SK, Márkus NM, Rua Martins R, Cooper-Knock J, Montmasson C, Cohen R, Walton A, Bauer CS, De Vos KJ, Mead RJ, Azzouz M, Dominguez C, Ferraiuolo L, Shaw PJ, Whitworth AJ, Hautbergue GM. A cell-penetrant peptide blocking C9ORF72-repeat RNA nuclear export reduces the neurotoxic effects of dipeptide repeat proteins. Sci Transl Med 2023; 15:eabo3823. [PMID: 36857431 DOI: 10.1126/scitranslmed.abo3823] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Hexanucleotide repeat expansions in C9ORF72 are the most common genetic cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Studies have shown that the hexanucleotide expansions cause the noncanonical translation of C9ORF72 transcripts into neurotoxic dipeptide repeat proteins (DPRs) that contribute to neurodegeneration. We show that a cell-penetrant peptide blocked the nuclear export of C9ORF72-repeat transcripts in HEK293T cells by competing with the interaction between SR-rich splicing factor 1 (SRSF1) and nuclear export factor 1 (NXF1). The cell-penetrant peptide also blocked the translation of toxic DPRs in neurons differentiated from induced neural progenitor cells (iNPCs), which were derived from individuals carrying C9ORF72-linked ALS mutations. This peptide also increased survival of iNPC-differentiated C9ORF72-ALS motor neurons cocultured with astrocytes. Oral administration of the cell-penetrant peptide reduced DPR translation and rescued locomotor deficits in a Drosophila model of mutant C9ORF72-mediated ALS/FTD. Intrathecal injection of this peptide into the brains of ALS/FTD mice carrying a C9ORF72 mutation resulted in reduced expression of DPRs in mouse brains. These findings demonstrate that disrupting the production of DPRs in cellular and animal models of ALS/FTD might be a strategy to ameliorate neurodegeneration in these diseases.
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Affiliation(s)
- Lydia M Castelli
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Ya-Hui Lin
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Alvaro Sanchez-Martinez
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Aytaç Gül
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Kamallia Mohd Imran
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Adrian Higginbottom
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Santosh Kumar Upadhyay
- Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Nóra M Márkus
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Raquel Rua Martins
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Johnathan Cooper-Knock
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Claire Montmasson
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Rebecca Cohen
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Amy Walton
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Claudia S Bauer
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Kurt J De Vos
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Richard J Mead
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Mimoun Azzouz
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Cyril Dominguez
- Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Laura Ferraiuolo
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
| | - Alexander J Whitworth
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Guillaume M Hautbergue
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385 Glossop Road, Sheffield S10 2HQ, UK
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5
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Dahal S, Clayton K, Been T, Fernet-Brochu R, Ocando AV, Balachandran A, Poirier M, Maldonado RK, Shkreta L, Boligan KF, Guvenc F, Rahman F, Branch D, Bell B, Chabot B, Gray-Owen SD, Parent LJ, Cochrane A. Opposing roles of CLK SR kinases in controlling HIV-1 gene expression and latency. Retrovirology 2022; 19:18. [PMID: 35986377 PMCID: PMC9389714 DOI: 10.1186/s12977-022-00605-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 07/29/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The generation of over 69 spliced HIV-1 mRNAs from one primary transcript by alternative RNA splicing emphasizes the central role that RNA processing plays in HIV-1 replication. Control is mediated in part through the action of host SR proteins whose activity is regulated by multiple SR kinases (CLK1-4, SRPKs). METHODS Both shRNA depletion and small molecule inhibitors of host SR kinases were used in T cell lines and primary cells to evaluate the role of these factors in the regulation of HIV-1 gene expression. Effects on virus expression were assessed using western blotting, RT-qPCR, and immunofluorescence. RESULTS The studies demonstrate that SR kinases play distinct roles; depletion of CLK1 enhanced HIV-1 gene expression, reduction of CLK2 or SRPK1 suppressed it, whereas CLK3 depletion had a modest impact. The opposing effects of CLK1 vs. CLK2 depletion were due to action at distinct steps; reduction of CLK1 increased HIV-1 promoter activity while depletion of CLK2 affected steps after transcript initiation. Reduced CLK1 expression also enhanced the response to several latency reversing agents, in part, by increasing the frequency of responding cells, consistent with a role in regulating provirus latency. To determine whether small molecule modulation of SR kinase function could be used to control HIV-1 replication, we screened a GSK library of protein kinase inhibitors (PKIS) and identified several pyrazolo[1,5-b] pyridazine derivatives that suppress HIV-1 gene expression/replication with an EC50 ~ 50 nM. The compounds suppressed HIV-1 protein and viral RNA accumulation with minimal impact on cell viability, inhibiting CLK1 and CLK2 but not CLK3 function, thereby selectively altering the abundance of individual CLK and SR proteins in cells. CONCLUSIONS These findings demonstrate the unique roles played by individual SR kinases in regulating HIV-1 gene expression, validating the targeting of these functions to either enhance latency reversal, essential for "Kick-and-Kill" strategies, or to silence HIV protein expression for "Block-and-Lock" strategies.
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Affiliation(s)
- Subha Dahal
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Kiera Clayton
- grid.168645.80000 0001 0742 0364Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Terek Been
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Raphaële Fernet-Brochu
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Alonso Villasmil Ocando
- grid.461656.60000 0004 0489 3491Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139 USA
| | - Ahalya Balachandran
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Mikaël Poirier
- grid.86715.3d0000 0000 9064 6198Dept. of Microbiology & Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC Canada
| | - Rebecca Kaddis Maldonado
- grid.240473.60000 0004 0543 9901Department of Medicine, Penn State College of Medicine, Hershey, PA 17033 USA ,grid.240473.60000 0004 0543 9901Microbiology & Immunology, Penn State College of Medicine, Hershey, PA 17033 USA
| | - Lulzim Shkreta
- grid.86715.3d0000 0000 9064 6198Dept. of Microbiology & Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC Canada
| | - Kayluz Frias Boligan
- grid.423370.10000 0001 0285 1288Center for Innovation, Canadian Blood Services, Toronto, ON Canada
| | - Furkan Guvenc
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Fariha Rahman
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Donald Branch
- grid.423370.10000 0001 0285 1288Center for Innovation, Canadian Blood Services, Toronto, ON Canada
| | - Brendan Bell
- grid.86715.3d0000 0000 9064 6198Dept. of Microbiology & Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC Canada
| | - Benoit Chabot
- grid.86715.3d0000 0000 9064 6198Dept. of Microbiology & Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC Canada
| | - Scott D. Gray-Owen
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
| | - Leslie J. Parent
- grid.240473.60000 0004 0543 9901Department of Medicine, Penn State College of Medicine, Hershey, PA 17033 USA ,grid.240473.60000 0004 0543 9901Microbiology & Immunology, Penn State College of Medicine, Hershey, PA 17033 USA
| | - Alan Cochrane
- grid.17063.330000 0001 2157 2938Dept. of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S1A8 Canada
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6
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Zhang X, Zhu YN, Chen B, Kang L. A Gypsy element contributes to the nuclear retention and transcriptional regulation of the resident lncRNA in locusts. RNA Biol 2022; 19:206-220. [PMID: 35067197 PMCID: PMC8786324 DOI: 10.1080/15476286.2021.2024032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The majority of long noncoding RNAs (lncRNAs) contain transposable elements (TEs). PAHAL, a nuclear-retained lncRNA that is inserted by a Gypsy retrotransposon, has been shown to be a vital regulator of phenylalanine hydroxylase (PAH) gene expression that controls dopamine biosynthesis and behavioural aggregation in the migratory locust. However, the role of the Gypsy retrotransposon in the transcriptional regulation of PAHAL remains unknown. Here, we identified a Gypsy retrotransposon (named Gypsy element) as an inverted long terminal repeat located in the 3′ end of PAHAL, representing a feature shared by many other lncRNAs in the locust genome. The embedded Gypsy element contains a RNA nuclear localization signal motif, which promotes the stable accumulation of PAHAL in the nucleus. The Gypsy element also provides high-affinity SRSF2 binding sites for PAHAL that induce the recruitment of SRSF2, resulting in the PAHAL-mediated transcriptional activation of PAH. Thus, our data demonstrate that TEs provide discrete functional domains for lncRNA organization and highlight the contribution of TEs to the regulatory significance of lncRNAs.
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Affiliation(s)
- Xia Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Ya Nan Zhu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Bing Chen
- School of Life Sciences, Hebei University, Baoding, China
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China.,School of Life Sciences, Hebei University, Baoding, China.,Beijing Institute of Life Sciences, Chinese Academy of Sciences, Beijing, China
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7
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Jobbins AM, Campagne S, Weinmeister R, Lucas CM, Gosliga AR, Clery A, Chen L, Eperon LP, Hodson MJ, Hudson AJ, Allain FHT, Eperon IC. Exon-independent recruitment of SRSF1 is mediated by U1 snRNP stem-loop 3. EMBO J 2022; 41:e107640. [PMID: 34779515 PMCID: PMC8724738 DOI: 10.15252/embj.2021107640] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 10/04/2021] [Accepted: 10/07/2021] [Indexed: 12/11/2022] Open
Abstract
SRSF1 protein and U1 snRNPs are closely connected splicing factors. They both stimulate exon inclusion, SRSF1 by binding to exonic splicing enhancer sequences (ESEs) and U1 snRNPs by binding to the downstream 5' splice site (SS), and both factors affect 5' SS selection. The binding of U1 snRNPs initiates spliceosome assembly, but SR proteins such as SRSF1 can in some cases substitute for it. The mechanistic basis of this relationship is poorly understood. We show here by single-molecule methods that a single molecule of SRSF1 can be recruited by a U1 snRNP. This reaction is independent of exon sequences and separate from the U1-independent process of binding to an ESE. Structural analysis and cross-linking data show that SRSF1 contacts U1 snRNA stem-loop 3, which is required for splicing. We suggest that the recruitment of SRSF1 to a U1 snRNP at a 5'SS is the basis for exon definition by U1 snRNP and might be one of the principal functions of U1 snRNPs in the core reactions of splicing in mammals.
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Affiliation(s)
- Andrew M Jobbins
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Present address:
MRC London Institute of Medical SciencesLondonUK
- Present address:
Institute of Clinical SciencesImperial College LondonLondonUK
| | - Sébastien Campagne
- Institute of BiochemistryETH ZürichSwitzerland
- Present address:
Inserm U1212CNRS UMR5320ARNA LaboratoryBordeaux CedexFrance
| | - Robert Weinmeister
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Leicester Institute of Structural & Chemical Biology and Department of ChemistryUniversity of LeicesterLeicesterUK
| | - Christian M Lucas
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Alison R Gosliga
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Present address:
Institut für Industrielle GenetikAbt.(eilung) SystembiologieUniversität StuttgartStuttgartGermany
| | | | - Li Chen
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Lucy P Eperon
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Mark J Hodson
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Andrew J Hudson
- Leicester Institute of Structural & Chemical Biology and Department of ChemistryUniversity of LeicesterLeicesterUK
| | | | - Ian C Eperon
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
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8
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Exploring the multifunctionality of SR proteins. Biochem Soc Trans 2021; 50:187-198. [PMID: 34940860 PMCID: PMC9022966 DOI: 10.1042/bst20210325] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 12/31/2022]
Abstract
Members of the arginine–serine-rich protein family (SR proteins) are multifunctional RNA-binding proteins that have emerged as key determinants for mRNP formation, identity and fate. They bind to pre-mRNAs early during transcription in the nucleus and accompany bound transcripts until they are translated or degraded in the cytoplasm. SR proteins are mostly known for their essential roles in constitutive splicing and as regulators of alternative splicing. However, many additional activities of individual SR proteins, beyond splicing, have been reported in recent years. We will summarize the different functions of SR proteins and discuss how multifunctionality can be achieved. We will also highlight the difficulties of studying highly versatile SR proteins and propose approaches to disentangle their activities, which is transferrable to other multifunctional RBPs.
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9
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Haward F, Maslon MM, Yeyati PL, Bellora N, Hansen JN, Aitken S, Lawson J, von Kriegsheim A, Wachten D, Mill P, Adams IR, Caceres JF. Nucleo-cytoplasmic shuttling of splicing factor SRSF1 is required for development and cilia function. eLife 2021; 10:e65104. [PMID: 34338635 PMCID: PMC8352595 DOI: 10.7554/elife.65104] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 07/30/2021] [Indexed: 12/02/2022] Open
Abstract
Shuttling RNA-binding proteins coordinate nuclear and cytoplasmic steps of gene expression. The SR family proteins regulate RNA splicing in the nucleus and a subset of them, including SRSF1, shuttles between the nucleus and cytoplasm affecting post-splicing processes. However, the physiological significance of this remains unclear. Here, we used genome editing to knock-in a nuclear retention signal (NRS) in Srsf1 to create a mouse model harboring an SRSF1 protein that is retained exclusively in the nucleus. Srsf1NRS/NRS mutants displayed small body size, hydrocephalus, and immotile sperm, all traits associated with ciliary defects. We observed reduced translation of a subset of mRNAs and decreased abundance of proteins involved in multiciliogenesis, with disruption of ciliary ultrastructure and motility in cells and tissues derived from this mouse model. These results demonstrate that SRSF1 shuttling is used to reprogram gene expression networks in the context of high cellular demands, as observed here, during motile ciliogenesis.
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Affiliation(s)
- Fiona Haward
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Magdalena M Maslon
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Patricia L Yeyati
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Nicolas Bellora
- Institute of Nuclear Technologies for Health (Intecnus), National Scientific and Technical Research Council (CONICET)BarilocheArgentina
| | - Jan N Hansen
- Institute of Innate Immunity, Biophysical Imaging, Medical Faculty, University of BonnBonnGermany
| | - Stuart Aitken
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Jennifer Lawson
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Alex von Kriegsheim
- Edinburgh Cancer Research United Kingdom Centre, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Dagmar Wachten
- Institute of Innate Immunity, Biophysical Imaging, Medical Faculty, University of BonnBonnGermany
| | - Pleasantine Mill
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Ian R Adams
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Javier F Caceres
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
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10
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Pastor F, Shkreta L, Chabot B, Durantel D, Salvetti A. Interplay Between CMGC Kinases Targeting SR Proteins and Viral Replication: Splicing and Beyond. Front Microbiol 2021; 12:658721. [PMID: 33854493 PMCID: PMC8040976 DOI: 10.3389/fmicb.2021.658721] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/04/2021] [Indexed: 12/27/2022] Open
Abstract
Protein phosphorylation constitutes a major post-translational modification that critically regulates the half-life, intra-cellular distribution, and activity of proteins. Among the large number of kinases that compose the human kinome tree, those targeting RNA-binding proteins, in particular serine/arginine-rich (SR) proteins, play a major role in the regulation of gene expression by controlling constitutive and alternative splicing. In humans, these kinases belong to the CMGC [Cyclin-dependent kinases (CDKs), Mitogen-activated protein kinases (MAPKs), Glycogen synthase kinases (GSKs), and Cdc2-like kinases (CLKs)] group and several studies indicate that they also control viral replication via direct or indirect mechanisms. The aim of this review is to describe known and emerging activities of CMGC kinases that share the common property to phosphorylate SR proteins, as well as their interplay with different families of viruses, in order to advance toward a comprehensive knowledge of their pro- or anti-viral phenotype and better assess possible translational opportunities.
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Affiliation(s)
- Florentin Pastor
- International Center for Infectiology Research (CIRI), INSERM U1111, CNRS UMR5308, Université de Lyon (UCBL1), Lyon, France
| | - Lulzim Shkreta
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Benoit Chabot
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - David Durantel
- International Center for Infectiology Research (CIRI), INSERM U1111, CNRS UMR5308, Université de Lyon (UCBL1), Lyon, France
| | - Anna Salvetti
- International Center for Infectiology Research (CIRI), INSERM U1111, CNRS UMR5308, Université de Lyon (UCBL1), Lyon, France
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11
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Chen X, Huang S, Jiang M, Chen Y, XuHan X, Zhang Z, Lin Y, Lai Z. Genome-wide identification and expression analysis of the SR gene family in longan (Dimocarpus longan Lour.). PLoS One 2020; 15:e0238032. [PMID: 32841304 PMCID: PMC7447046 DOI: 10.1371/journal.pone.0238032] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 08/07/2020] [Indexed: 12/05/2022] Open
Abstract
Longan (Dimocarpus longan Lour.) is an important commercial fruit tree in southern China. The embryogenesis of longan affects the quality and yield of fruit. A large number of alternative splicing events occurs during somatic embryogenesis (SE), which is regulated by serine/arginine-rich (SR) proteins. However, the functions of SR proteins in longan are poorly understood. In this study, 21 Dlo-SR gene family members belonging to six subfamilies were identified, among which Dlo-RSZ20a, Dlo-SR30, Dlo-SR17, Dlo-SR53 and Dlo-SR32 were localized in the nucleus, Dlo-RSZ20b, Dlo-RSZ20c, Dlo-RSZ20d, Dlo-SC18, Dlo-RS2Z29, Dlo-SCL41, and Dlo-SR33 were localized in chloroplasts, and Dlo-RS43, Dlo-SC33, Dlo-SC37, Dlo-RS2Z33, Dlo-RS2Z16, Dlo-RS2Z24, Dlo-SCL43, Dlo-SR112, and Dlo-SR59 were localized in the nucleus and chloroplasts. The Dlo-SR genes exhibited differential expression patterns in different tissues of longan. The transcript levels of Dlo-RSZ20a, Dlo-SC18, Dlo-RS2Z29, DLo-SR59, Dlo-SR53, and Dlo-SR17 were low in all analyzed tissues, whereas Dlo-RS43, Dlo-RS2Z16, Dlo-RS2Z24, and Dlo-SR30 were highly expressed in all tissues. To clarify their function during SE, the transcript levels of Dlo-SR genes were analyzed at different four stages of SE, comprising non-embryonic callus (NEC), friable-embryogenic callus (EC), incomplete compact pro-embryogenic culture (ICpEC) and globular embryo (GE). Interestingly, the transcript levels of Dlo-RS2Z29 and Dlo-SR112 were increased in embryogenic cells compared with the NEC stage, whereas transcript levels of Dlo-RSZ20a, Dlo-RS43, Dlo-SC37, and Dlo-RS2Z16 were especially increased at the GE stage compared with the other stages. Alternative splicing events of Dlo-SR mRNA precursors (pre-mRNAs) was detected during SE, with totals of 41, 29, 35, and 44 events detected during NEC, EC, ICpEC, and GE respectively. Protein–protein interaction analysis showed that SR proteins were capable of interaction with each other. The results indicate that the alternative splicing of Dlo-SR pre-mRNAs occurs during SE and that Dlo-SR proteins may interact to regulate embryogenesis of longan.
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Affiliation(s)
- Xiaodong Chen
- Institute of horticultural biotechnology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shuqi Huang
- Institute of horticultural biotechnology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Mengqi Jiang
- Institute of horticultural biotechnology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yukun Chen
- Institute of horticultural biotechnology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xu XuHan
- Institute of horticultural biotechnology, Fujian Agriculture and Forestry University, Fuzhou, China
- Institute de la Recherche Interdisciplinaire de Toulouse, Toulouse, France
| | - Zihao Zhang
- Institute of horticultural biotechnology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yuling Lin
- Institute of horticultural biotechnology, Fujian Agriculture and Forestry University, Fuzhou, China
- * E-mail: (YL); (ZL)
| | - Zhongxiong Lai
- Institute of horticultural biotechnology, Fujian Agriculture and Forestry University, Fuzhou, China
- * E-mail: (YL); (ZL)
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12
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Zhang X, Xu Y, Chen B, Kang L. Long noncoding RNA PAHAL modulates locust behavioural plasticity through the feedback regulation of dopamine biosynthesis. PLoS Genet 2020; 16:e1008771. [PMID: 32348314 PMCID: PMC7241820 DOI: 10.1371/journal.pgen.1008771] [Citation(s) in RCA: 16] [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: 01/15/2020] [Revised: 05/21/2020] [Accepted: 04/09/2020] [Indexed: 11/24/2022] Open
Abstract
Some long noncoding RNAs (lncRNAs) are specifically expressed in brain cells, implying their neural and behavioural functions. However, how lncRNAs contribute to neural regulatory networks governing the precise behaviour of animals is less explored. Here, we report the regulatory mechanism of the nuclear-enriched lncRNA PAHAL for dopamine biosynthesis and behavioural adjustment in migratory locusts (Locusta migratoria), a species with extreme behavioral plasticity. PAHAL is transcribed from the sense (coding) strand of the gene encoding phenylalanine hydroxylase (PAH), which is responsible for the synthesis of dopamine from phenylalanine. PAHAL positively regulates PAH expression resulting in dopamine production in the brain. In addition, PAHAL modulates locust behavioral aggregation in a population density-dependent manner. Mechanistically, PAHAL mediates PAH transcriptional activation by recruiting serine/arginine-rich splicing factor 2 (SRSF2), a transcription/splicing factor, to the PAH proximal promoter. The co-activation effect of PAHAL requires the interaction of the PAHAL/SRSF2 complex with the promoter-associated nascent RNA of PAH. Thus, the data support a model of feedback modulation of animal behavioural plasticity by an lncRNA. In this model, the lncRNA mediates neurotransmitter metabolism through orchestrating a local transcriptional loop. The neurotransmitter dopamine is crucial for the neuronal and behavioral response in animals. Phenylalanine hydroxylase (PAH) is involved in dopamine biosynthesis and behavioral regulation in the migratory locust. However, the molecular mechanism for the fine tuning of PAH expression in behavioral response remains ambiguous. Here we discovered a nuclear-enriched lncRNA PAHAL that is transcribed from the coding strand of the PAH gene in the locust (i.e., sense lncRNA). PAHAL positively regulated PAH expression and dopamine production in the brain. In addition, PAHAL modulated behavioral aggregation of the locust. Mechanistically, PAHAL mediated the transcriptional activation of PAH by recruiting SRSF2, a transcription/splicing factor, to the promoter-associated nascent RNA of PAH. These data support a model of feedback modulation of dopamine biosynthesis and behavioral plasticity via a sense lncRNA in the catecholamine metabolic pathway.
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Affiliation(s)
- Xia Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Beijing Institute of Life Sciences, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Ya'nan Xu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Bing Chen
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, Hebei University, Baoding, China
- * E-mail: (BC); (KL)
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Beijing Institute of Life Sciences, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, Hebei University, Baoding, China
- * E-mail: (BC); (KL)
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13
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The X-linked trichothiodystrophy-causing gene RNF113A links the spliceosome to cell survival upon DNA damage. Nat Commun 2020; 11:1270. [PMID: 32152280 PMCID: PMC7062854 DOI: 10.1038/s41467-020-15003-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 02/17/2020] [Indexed: 12/30/2022] Open
Abstract
Prolonged cell survival occurs through the expression of specific protein isoforms generated by alternate splicing of mRNA precursors in cancer cells. How alternate splicing regulates tumor development and resistance to targeted therapies in cancer remain poorly understood. Here we show that RNF113A, whose loss-of-function causes the X-linked trichothiodystrophy, is overexpressed in lung cancer and protects from Cisplatin-dependent cell death. RNF113A is a RNA-binding protein which regulates the splicing of multiple candidates involved in cell survival. RNF113A deficiency triggers cell death upon DNA damage through multiple mechanisms, including apoptosis via the destabilization of the prosurvival protein MCL-1, ferroptosis due to enhanced SAT1 expression, and increased production of ROS due to altered Noxa1 expression. RNF113A deficiency circumvents the resistance to Cisplatin and to BCL-2 inhibitors through the destabilization of MCL-1, which thus defines spliceosome inhibitors as a therapeutic approach to treat tumors showing acquired resistance to specific drugs due to MCL-1 stabilization. Alternate splicing of mRNA precursors has been linked to tumor development. Here the authors reveal a role of the E3 ligase RNF113A in spliceosome regulation affecting cell survival upon DNA damage.
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14
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Masaki S, Kabuto T, Suzuki K, Kataoka N. Multiple nuclear localization sequences in SRSF4 protein. Genes Cells 2020; 25:327-333. [PMID: 32050040 DOI: 10.1111/gtc.12756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/07/2020] [Accepted: 02/10/2020] [Indexed: 11/29/2022]
Abstract
SRSF4 is one of the members of serine-/arginine (SR)-rich protein family involved in both constitutive and alternative splicing. SRSF4 is localized in the nucleus with speckled pattern, but its nuclear localization signal was not determined. Here, we have identified nuclear localization signals (NLSs) of SRSF4 by using a pyruvate kinase fusion system. As expected, arginine-/serine (RS)-rich domain of SRSF4 confers nuclear localization activity when it is fused to PK protein. We then further delineated the minimum sequences for nuclear localization in RS domain of SRSF4. Surprisingly, RS-rich region does not always have a nuclear localization activity. In addition, basic amino acid stretches that resemble to classical-type NLSs were identified. These results strongly suggest that SRSF4 protein uses two different nuclear import pathways with multiple NLSs in RS domain.
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Affiliation(s)
- So Masaki
- Laboratory for Malignancy Control Research, Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Laboratory of Molecular Medicinal Science, Department of Pharmaceutical Sciences, Ritsumeikan University, Shiga, Japan
| | - Takafumi Kabuto
- Laboratory of Anatomy and Developmental Biology, Kyoto University School of Medicine, Kyoto, Japan
| | - Kenji Suzuki
- Laboratory of Molecular Medicinal Science, Department of Pharmaceutical Sciences, Ritsumeikan University, Shiga, Japan
| | - Naoyuki Kataoka
- Laboratory for Malignancy Control Research, Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Laboratory of Anatomy and Developmental Biology, Kyoto University School of Medicine, Kyoto, Japan.,Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
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15
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View from an mRNP: The Roles of SR Proteins in Assembly, Maturation and Turnover. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1203:83-112. [PMID: 31811631 DOI: 10.1007/978-3-030-31434-7_3] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Serine- and arginine-rich proteins (SR proteins) are a family of multitasking RNA-binding proteins (RBPs) that are key determinants of messenger ribonucleoprotein (mRNP) formation, identity and fate. Apart from their essential functions in pre-mRNA splicing, SR proteins display additional pre- and post-splicing activities and connect nuclear and cytoplasmic gene expression machineries. Through changes in their post-translational modifications (PTMs) and their subcellular localization, they provide functional specificity and adjustability to mRNPs. Transcriptome-wide UV crosslinking and immunoprecipitation (CLIP-Seq) studies revealed that individual SR proteins are present in distinct mRNPs and act in specific pairs to regulate different gene expression programmes. Adopting an mRNP-centric viewpoint, we discuss the roles of SR proteins in the assembly, maturation, quality control and turnover of mRNPs and describe the mechanisms by which they integrate external signals, coordinate their multiple tasks and couple subsequent mRNA processing steps.
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16
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McNicoll F, Müller-McNicoll M. A Quantitative Heterokaryon Assay to Measure the Nucleocytoplasmic Shuttling of Proteins. Bio Protoc 2018; 8:e2472. [PMID: 34395784 DOI: 10.21769/bioprotoc.2472] [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: 09/04/2017] [Revised: 12/03/2017] [Accepted: 01/03/2018] [Indexed: 11/02/2022] Open
Abstract
Many proteins appear exclusively nuclear at steady-state but in fact shuttle continuously back and forth between the nucleus and the cytoplasm. For example, nuclear RNA-binding proteins (RBPs) often accompany mRNAs to the cytoplasm, where they can regulate subcellular localization, translation and/or decay of their cargos before shuttling back to the nucleus. Nucleocytoplasmic shuttling must be tightly regulated, as mislocalization of several RBPs with prion-like domains such as FUS and TDP-43 causes the cytoplasmic accumulation of solid pathological aggregates that have been implicated in neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Traditionally, interspecies heterokaryon assays have been used to determine whether a nuclear protein of interest shuttles; those assays are based on the fusion between donor and recipient cells from two different species (e.g., mouse and human), which can be distinguished based on different chromatin staining patterns, and detecting the appearance of the protein in the recipient nucleus. However, identification of heterokaryons requires experience and is prone to error, which makes it difficult to obtain high-quality data for quantitative studies. Moreover, transient overexpression of fluorescently tagged RBPs in donor cells often leads to their aberrant subcellular localization. Here, we present a quantitative assay where stable donor cell lines expressing near-physiological levels of eGFP-tagged RBPs are fused to recipient cells expressing the membrane marker CAAX-mCherry, allowing to readily identify and image a large number of high-confidence heterokaryons. Our assay can be used to measure the shuttling activity of any nuclear protein of interest in different cell types, under different cellular conditions or between mutant proteins.
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Affiliation(s)
- François McNicoll
- RNA Regulation Group, Goethe University Frankfurt, Institute of Cell Biology and Neuroscience, Frankfurt/Main, Germany
| | - Michaela Müller-McNicoll
- RNA Regulation Group, Goethe University Frankfurt, Institute of Cell Biology and Neuroscience, Frankfurt/Main, Germany
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17
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Wegener M, Müller-McNicoll M. Nuclear retention of mRNAs - quality control, gene regulation and human disease. Semin Cell Dev Biol 2017; 79:131-142. [PMID: 29102717 DOI: 10.1016/j.semcdb.2017.11.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/30/2017] [Accepted: 11/01/2017] [Indexed: 12/21/2022]
Abstract
Nuclear retention of incompletely spliced or mature mRNAs emerges as a novel, previously underappreciated layer of gene regulation, which enables the cell to rapidly respond to stress, viral infection, differentiation cues or changing environmental conditions. Focusing on mammalian cells, we discuss recent insights into the mechanisms and functions of nuclear retention, describe retention-promoting features in protein-coding transcripts and propose mechanisms for their regulated release into the cytoplasm. Moreover, we discuss examples of how aberrant nuclear retention of mRNAs may lead to human diseases.
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Affiliation(s)
- Marius Wegener
- RNA Regulation Group, Cluster of Excellence 'Macromolecular Complexes', Goethe University Frankfurt, Institute of Cell Biology and Neuroscience, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany
| | - Michaela Müller-McNicoll
- RNA Regulation Group, Cluster of Excellence 'Macromolecular Complexes', Goethe University Frankfurt, Institute of Cell Biology and Neuroscience, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany.
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18
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Fei J, Jadaliha M, Harmon TS, Li ITS, Hua B, Hao Q, Holehouse AS, Reyer M, Sun Q, Freier SM, Pappu RV, Prasanth KV, Ha T. Quantitative analysis of multilayer organization of proteins and RNA in nuclear speckles at super resolution. J Cell Sci 2017; 130:4180-4192. [PMID: 29133588 DOI: 10.1242/jcs.206854] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 11/01/2017] [Indexed: 12/30/2022] Open
Abstract
Nuclear speckles are self-assembled organelles composed of RNAs and proteins. They are proposed to act as structural domains that control distinct steps in gene expression, including transcription, splicing and mRNA export. Earlier studies identified differential localization of a few components within the speckles. It was speculated that the spatial organization of speckle components might contribute directly to the order of operations that coordinate distinct processes. Here, by performing multi-color structured illumination microscopy, we characterized the multilayer organization of speckles at a higher resolution. We found that SON and SC35 (also known as SRSF2) localize to the central region of the speckle, whereas MALAT1 and small nuclear (sn)RNAs are enriched at the speckle periphery. Coarse-grained simulations indicate that the non-random organization arises due to the interplay between favorable sequence-encoded intermolecular interactions of speckle-resident proteins and RNAs. Finally, we observe positive correlation between the total amount of RNA present within a speckle and the speckle size. These results imply that speckle size may be regulated to accommodate RNA accumulation and processing. Accumulation of RNA from various actively transcribed speckle-associated genes could contribute to the observed speckle size variations within a single cell.
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Affiliation(s)
- Jingyi Fei
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA .,Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
| | - Mahdieh Jadaliha
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Tyler S Harmon
- Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Isaac T S Li
- Department of Chemistry, University of British Columbia Okanagan, Kelowna, British Columbia, Canada, V1V 1V7
| | - Boyang Hua
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Qinyu Hao
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Alex S Holehouse
- Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Matthew Reyer
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
| | - Qinyu Sun
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | | | - Rohit V Pappu
- Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Kannanganattu V Prasanth
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Taekjip Ha
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Department of Physics, Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Howard Hughes Medical Institute, Johns Hopkins University, Baltimore, MD 21205, USA
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19
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Botti V, McNicoll F, Steiner MC, Richter FM, Solovyeva A, Wegener M, Schwich OD, Poser I, Zarnack K, Wittig I, Neugebauer KM, Müller-McNicoll M. Cellular differentiation state modulates the mRNA export activity of SR proteins. J Cell Biol 2017; 216:1993-2009. [PMID: 28592444 PMCID: PMC5496613 DOI: 10.1083/jcb.201610051] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 03/22/2017] [Accepted: 04/24/2017] [Indexed: 01/22/2023] Open
Abstract
SR proteins connect nuclear pre-mRNA processing to mRNA export and translation. Botti et al. develop a quantitative nucleocytoplasmic shuttling assay and show that SR proteins are differentially modified and active in differentiated and pluripotent cells. SR proteins function in nuclear pre-mRNA processing, mRNA export, and translation. To investigate their cellular dynamics, we developed a quantitative assay, which detects differences in nucleocytoplasmic shuttling among seven canonical SR protein family members. As expected, SRSF2 and SRSF5 shuttle poorly in HeLa cells but surprisingly display considerable shuttling in pluripotent murine P19 cells. Combining individual-resolution cross-linking and immunoprecipitation (iCLIP) and mass spectrometry, we show that elevated arginine methylation of SRSF5 and lower phosphorylation levels of cobound SRSF2 enhance shuttling of SRSF5 in P19 cells by modulating protein–protein and protein–RNA interactions. Moreover, SRSF5 is bound to pluripotency-specific transcripts such as Lin28a and Pou5f1/Oct4 in the cytoplasm. SRSF5 depletion reduces and overexpression increases their cytoplasmic mRNA levels, suggesting that enhanced mRNA export by SRSF5 is required for the expression of pluripotency factors. Remarkably, neural differentiation of P19 cells leads to dramatically reduced SRSF5 shuttling. Our findings indicate that posttranslational modification of SR proteins underlies the regulation of their mRNA export activities and distinguishes pluripotent from differentiated cells.
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Affiliation(s)
- Valentina Botti
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - François McNicoll
- Cluster of Excellence Macromolecular Complexes, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Michaela C Steiner
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Florian M Richter
- Functional Proteomics Group, Institute for Biochemistry I, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Anfisa Solovyeva
- Cluster of Excellence Macromolecular Complexes, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Marius Wegener
- Cluster of Excellence Macromolecular Complexes, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany.,Buchmann Institute for Molecular Life Sciences, Frankfurt am Main, Germany
| | - Oliver D Schwich
- Cluster of Excellence Macromolecular Complexes, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany.,Buchmann Institute for Molecular Life Sciences, Frankfurt am Main, Germany
| | - Ina Poser
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences, Frankfurt am Main, Germany
| | - Ilka Wittig
- Functional Proteomics Group, Institute for Biochemistry I, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - Michaela Müller-McNicoll
- Cluster of Excellence Macromolecular Complexes, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany
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20
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Zhou J, Gao G, Hou P, Li CM, Guo D. Regulation of the Alternative Splicing and Function of Cyclin T1 by the Serine-Arginine-Rich Protein ASF/SF2. J Cell Biochem 2017; 118:4020-4032. [PMID: 28422315 DOI: 10.1002/jcb.26058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/11/2017] [Indexed: 02/04/2023]
Abstract
Positive transcription elongation factor-b (P-TEFb) is required for the release of RNA polymerase II (RNAPII) from its pause near the gene promoters and thus for efficient proceeding to the transcription elongation. It consists of two core subunits-CDK9 and one of T-typed or K-typed cyclin, of which, cyclin T1/CDK9 is the major and most studied combination. We have previously identified a novel splice variant of cyclin T1, cyclin T1b, which negatively regulates the transcription elongation of HIV-1 genes as well as several host genes. In this study, we revealed the serine-arginine-rich protein, ASF/SF2, as a regulatory factor of the alternative splicing of cyclin T1 gene. ASF/SF2 promotes the production of cyclin T1b versus cyclin T1a and regulates the expression of cyclin T1-depedent genes at the transcription level. We further found that a cis-element on exon 8 is responsible for the skipping of exon 7 mediated by ASF/SF2. Collectively, ASF/SF2 is identified as a splicing regulator of cyclin T1, which contributes to the control of the subsequent transcription events. J. Cell. Biochem. 118: 4020-4032, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Jieqiong Zhou
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Guozhen Gao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Panpan Hou
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Chun-Mei Li
- School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Deyin Guo
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.,School of Basic Medical Sciences, Wuhan University, Wuhan, China
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21
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Abstract
Tumor-associated alterations in RNA splicing result either from mutations in splicing-regulatory elements or changes in components of the splicing machinery. This review summarizes our current understanding of the role of splicing-factor alterations in human cancers. We describe splicing-factor alterations detected in human tumors and the resulting changes in splicing, highlighting cell-type-specific similarities and differences. We review the mechanisms of splicing-factor regulation in normal and cancer cells. Finally, we summarize recent efforts to develop novel cancer therapies, based on targeting either the oncogenic splicing events or their upstream splicing regulators.
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Affiliation(s)
- Olga Anczuków
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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22
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Müller-McNicoll M, Botti V, de Jesus Domingues AM, Brandl H, Schwich OD, Steiner MC, Curk T, Poser I, Zarnack K, Neugebauer KM. SR proteins are NXF1 adaptors that link alternative RNA processing to mRNA export. Genes Dev 2016; 30:553-66. [PMID: 26944680 PMCID: PMC4782049 DOI: 10.1101/gad.276477.115] [Citation(s) in RCA: 215] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this study, Müller-McNicoll et al. investigate how export machinery assembles on mRNA and how it senses mRNA maturity before exporting mRNAs from the nucleus. They show that SR proteins act as NXF1 adaptors by connecting alternative splicing and 3′ end formation to mRNA export in vivo and propose that SR proteins and NXF1 form a ternary complex on mRNAs, particularly in last exons, and shuttle together to the cytoplasm. Nuclear export factor 1 (NXF1) exports mRNA to the cytoplasm after recruitment to mRNA by specific adaptor proteins. How and why cells use numerous different export adaptors is poorly understood. Here we critically evaluate members of the SR protein family (SRSF1–7) for their potential to act as NXF1 adaptors that couple pre-mRNA processing to mRNA export. Consistent with this proposal, >1000 endogenous mRNAs required individual SR proteins for nuclear export in vivo. To address the mechanism, transcriptome-wide RNA-binding profiles of NXF1 and SRSF1–7 were determined in parallel by individual-nucleotide-resolution UV cross-linking and immunoprecipitation (iCLIP). Quantitative comparisons of RNA-binding sites showed that NXF1 and SR proteins bind mRNA targets at adjacent sites, indicative of cobinding. SRSF3 emerged as the most potent NXF1 adaptor, conferring sequence specificity to RNA binding by NXF1 in last exons. Interestingly, SRSF3 and SRSF7 were shown to bind different sites in last exons and regulate 3′ untranslated region length in an opposing manner. Both SRSF3 and SRSF7 promoted NXF1 recruitment to mRNA. Thus, SRSF3 and SRSF7 couple alternative splicing and polyadenylation to NXF1-mediated mRNA export, thereby controlling the cytoplasmic abundance of transcripts with alternative 3′ ends.
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Affiliation(s)
- Michaela Müller-McNicoll
- RNA Regulation Group, Institute of Cell Biology and Neuroscience, Goethe-University Frankfurt, 60438 Frankfurt/Main, Germany
| | - Valentina Botti
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | | | - Holger Brandl
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Oliver D Schwich
- RNA Regulation Group, Institute of Cell Biology and Neuroscience, Goethe-University Frankfurt, 60438 Frankfurt/Main, Germany; Buchmann Institute for Life Sciences (BMLS), 60438 Frankfurt/Main, Germany
| | - Michaela C Steiner
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Tomaz Curk
- Faculty of Computer and Information Science, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Ina Poser
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Kathi Zarnack
- Buchmann Institute for Life Sciences (BMLS), 60438 Frankfurt/Main, Germany
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
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23
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Kadri F, Pacifici M, Wilk A, Parker-Struckhoff A, Del Valle L, Hauser KF, Knapp PE, Parsons C, Jeansonne D, Lassak A, Peruzzi F. HIV-1-Tat Protein Inhibits SC35-mediated Tau Exon 10 Inclusion through Up-regulation of DYRK1A Kinase. J Biol Chem 2015; 290:30931-46. [PMID: 26534959 PMCID: PMC4692221 DOI: 10.1074/jbc.m115.675751] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 11/02/2015] [Indexed: 01/08/2023] Open
Abstract
The HIV-1 transactivator protein Tat is implicated in the neuronal damage that contributes to neurocognitive impairment affecting people living with HIV/AIDS. Aberrant splicing of TAU exon 10 results in tauopathies characterized by alterations in the proportion of TAU isoforms containing three (3R) or four (4R) microtubule-binding repeats. The splicing factor SC35/SRSF2 binds to nuclear RNA and facilitates the incorporation of exon 10 in the TAU molecule. Here, we utilized clinical samples, an animal model, and neuronal cell cultures and found that Tat promotes TAU 3R up-regulation through increased levels of phosphorylated SC35, which is retained in nuclear speckles. This mechanism involved Tat-mediated increased expression of DYRK1A and was prevented by DYRK1A silencing. In addition, we found that Tat associates with TAU RNA, further demonstrating that Tat interferes with host RNA metabolism in the absence of viral infection. Altogether, our data unravel a novel mechanism of Tat-mediated neuronal toxicity through dysregulation of the SC35-dependent alternative splicing of TAU exon 10. Furthermore, the increased immunostaining of DYRK1A in HIV+ brains without pathology points at dysregulation of DYRK1A as an early event in the neuronal complications of HIV infection.
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Affiliation(s)
- Ferdous Kadri
- From the Department of Medicine, Stanley S. Scott Cancer Center, and Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112 and
| | - Marco Pacifici
- From the Department of Medicine, Stanley S. Scott Cancer Center, and
| | - Anna Wilk
- From the Department of Medicine, Stanley S. Scott Cancer Center, and
| | | | - Luis Del Valle
- From the Department of Medicine, Stanley S. Scott Cancer Center, and
| | | | - Pamela E Knapp
- Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia 23284
| | | | - Duane Jeansonne
- From the Department of Medicine, Stanley S. Scott Cancer Center, and
| | - Adam Lassak
- From the Department of Medicine, Stanley S. Scott Cancer Center, and
| | - Francesca Peruzzi
- From the Department of Medicine, Stanley S. Scott Cancer Center, and
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24
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Albert GI, Schell C, Kirschner KM, Schäfer S, Naumann R, Müller A, Kretz O, Kuropka B, Girbig M, Hübner N, Krause E, Scholz H, Huber TB, Knobeloch KP, Freund C. The GYF domain protein CD2BP2 is critical for embryogenesis and podocyte function. J Mol Cell Biol 2015; 7:402-14. [PMID: 26082520 DOI: 10.1093/jmcb/mjv039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 04/15/2015] [Indexed: 01/11/2023] Open
Abstract
Scaffolding proteins play pivotal roles in the assembly of macromolecular machines such as the spliceosome. The adaptor protein CD2BP2, originally identified as a binding partner of the adhesion molecule CD2, is a pre-spliceosomal assembly factor that utilizes its glycine-tyrosine-phenylalanine (GYF) domain to co-localize with spliceosomal proteins. So far, its function in vertebrates is unknown. Using conditional gene targeting in mice, we show that CD2BP2 is crucial for embryogenesis, leading to growth retardation, defects in vascularization, and premature death at embryonic day 10.5 when absent. Ablation of the protein in bone marrow-derived macrophages indicates that CD2BP2 is involved in the alternative splicing of mRNA transcripts from diverse origins. At the molecular level, we identified the phosphatase PP1 to be recruited to the spliceosome via the N-terminus of CD2BP2. Given the strong expression of CD2BP2 in podocytes of the kidney, we use selective depletion of CD2BP2, in combination with next-generation sequencing, to monitor changes in exon usage of genes critical for podocyte functions, including VEGF and actin regulators. CD2BP2-depleted podocytes display foot process effacement, and cause proteinuria and ultimately lethal kidney failure in mice. Collectively, our study defines CD2BP2 as a non-redundant splicing factor essential for embryonic development and podocyte integrity.
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Affiliation(s)
- Gesa I Albert
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany Leibniz-Institut fuer Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Christoph Schell
- Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany Speman Graduate School for Medicine and Biology, University of Freiburg, 79106 Freiburg, Germany Faculty of Biology, University Freiburg, 79106 Freiburg, Germany
| | - Karin M Kirschner
- Institute fuer Vegetative Physiologie, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Sebastian Schäfer
- Experimental Genetics and Cardiovascular Diseases, MDC, 13125 Berlin, Germany
| | - Ronald Naumann
- Transgenic Core Facility, Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Alexandra Müller
- Institute of Neuropathology, University of Freiburg, 79106 Freiburg, Germany
| | - Oliver Kretz
- Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany Institute of Cell Biology & Anatomy, University of Freiburg, 79106 Freiburg, Germany
| | - Benno Kuropka
- Leibniz-Institut fuer Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Mathias Girbig
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Norbert Hübner
- Experimental Genetics and Cardiovascular Diseases, MDC, 13125 Berlin, Germany
| | - Eberhard Krause
- Leibniz-Institut fuer Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Holger Scholz
- Institute fuer Vegetative Physiologie, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Tobias B Huber
- Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany Speman Graduate School for Medicine and Biology, University of Freiburg, 79106 Freiburg, Germany BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University, 79106 Freiburg, Germany
| | | | - Christian Freund
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany Leibniz-Institut fuer Molekulare Pharmakologie, 13125 Berlin, Germany
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25
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Mo S, Ji X, Fu XD. Unique role of SRSF2 in transcription activation and diverse functions of the SR and hnRNP proteins in gene expression regulation. Transcription 2015; 4:251-9. [PMID: 24406341 DOI: 10.4161/trns.26932] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Transcription pause release from gene promoters has been recognized to be a critical point for transcriptional regulation in higher eukaryotes. Recent studies suggest that regulatory RNAs are extensively involved in transcriptional control, which may enlist various RNA binding proteins. We recently showed a key role of SRSF2, a member of the SR family of splicing regulators, in binding to promoter-associated small RNA to mediate transcription pause release, a regulatory strategy akin to the function of the HIV Tat protein via binding to the TAR element in nascent RNA to activate transcription. In this report, we further dissect the structural requirement for SRSF2 to function as a transcription activator and extend the analysis to multiple SR and hnRNP proteins by using the MS2 tethering strategy. Our results reveal that SRSF2 is a unique SR protein that activates transcription in a position-dependent manner while three other SR proteins enhance translation in a position-independent fashion. In contrast, multiple hnRNP proteins appear to negatively influence mRNA levels, especially when tethered in the gene body. These findings suggest broad participation of RNA binding proteins in diverse aspects of regulated gene expression at both the transcriptional and posttranscriptional levels in mammalian cells.
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26
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Ceramide modulates pre-mRNA splicing to restore the expression of wild-type tumor suppressor p53 in deletion-mutant cancer cells. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1571-80. [PMID: 25195822 DOI: 10.1016/j.bbalip.2014.08.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 07/25/2014] [Accepted: 08/27/2014] [Indexed: 11/20/2022]
Abstract
Mutants of tumor suppressor p53 not only lose the activity in genome stabilizing and in tumor suppression, but also exhibit oncogenic function in cancer cells. Most efforts in restoring p53 biological activity focus on either altering mutant-protein conformation or introducing an exogenous p53 gene into cells to eliminate p53-mutant cancer cells. Being different from these, we report that ceramide can restore the expression of wild-type p53 and induce p53-dependent apoptosis in deletion-mutant cancer cells. We show that endogenous long-carbon chain ceramide species (C16- to C24-ceramides) and exogenous C6-ceramide, rather than other sphingolipids, restore wild-type mRNA (intact exon-5), phosphorylated protein (Ser15 in exon-5) of p53, and p53-responsive proteins, including p21 and Bax, in ovarian cancer cells, which predominantly express a deleted exon-5 of p53 mutant before treatments. Consequently, the restored p53 sensitizes these p53-mutant cancer cells to DNA damage-induced growth arrest and apoptosis. Furthermore, we elucidate that ceramide activates protein phosphatase-1, and then the dephosphorylated serine/arginine-rich splicing-factor 1 (SRSF1) is translocated to the nucleus, thus promoting pre-mRNA splicing preferentially to wild-type p53 expression. These findings disclose an unrecognized mechanism that pre-mRNA splicing dysfunction can result in p53 deletion-mutants. Ceramide through SRSF1 restores wild-type p53 expression versus deletion-mutant and leads cancer cells to apoptosis. This suggests that heterozygous deletion-mutants of p53 can be restored in posttranscriptional level by using epigenetic approaches.
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27
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Howard JM, Sanford JR. The RNAissance family: SR proteins as multifaceted regulators of gene expression. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 6:93-110. [PMID: 25155147 DOI: 10.1002/wrna.1260] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/09/2014] [Accepted: 07/14/2014] [Indexed: 12/29/2022]
Abstract
Serine and arginine-rich (SR) proteins play multiple roles in the eukaryotic gene expression pathway. Initially described as constitutive and alternative splicing factors, now it is clear that SR proteins are key determinants of exon identity and function as molecular adaptors, linking the pre-messenger RNA (pre-mRNA) to the splicing machinery. In addition, now SR proteins are implicated in many aspects of mRNA and noncoding RNA (ncRNA) processing well beyond splicing. These unexpected roles, including RNA transcription, export, translation, and decay, may prove to be the rule rather than the exception. To simply define, this family of RNA-binding proteins as splicing factors belies the broader roles of SR proteins in post-transcriptional gene expression.
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Affiliation(s)
- Jonathan M Howard
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, USA
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28
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Strengert M, Jennings R, Davanture S, Hayes P, Gabriel G, Knaus UG. Mucosal reactive oxygen species are required for antiviral response: role of Duox in influenza a virus infection. Antioxid Redox Signal 2014; 20:2695-709. [PMID: 24128054 DOI: 10.1089/ars.2013.5353] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AIMS Influenza A virus (IAV), a major airborne pathogen, is closely associated with significant morbidity and mortality. The primary target for influenza virus replication is the respiratory epithelium, which reacts to infection by mounting a multifaceted antiviral response. A part of this mucosal host defense is the generation of reactive oxygen species (ROS) by NADPH oxidases. Duox1 and Duox2 are the main ROS-producing enzymes in the airway epithelium, but their contribution to mammalian host defense is still ill defined. RESULTS To gain a better understanding of Duox function in respiratory tract infections, human differentiated lung epithelial cells and an animal model were used to monitor the effect of epithelial ROS on IAV propagation. IAV infection led to coordinated up-regulation of Duox2 and Duox-mediated ROS generation. Interference with H2O2 production and ROS signaling by oxidase inhibition or H2O2 decomposition augmented IAV replication. A nuclear pool of Duox enzymes participated in the regulation of the spliceosome, which is critical for alternative splicing of viral transcripts and controls the assembly of viable virions. In vivo silencing of Duox increased the viral load on intranasal infection with 2009 pandemic H1N1 influenza virus. INNOVATION This is the first study conclusively linking Duox NADPH oxidases with the antiviral mammalian immune response. Further, ROS generated by Duox enzymes localized adjacent to nuclear speckles altered the splicing of viral genes. CONCLUSION Duox-derived ROS are host protective and essential for counteracting IAV replication.
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29
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Naro C, Barbagallo F, Chieffi P, Bourgeois CF, Paronetto MP, Sette C. The centrosomal kinase NEK2 is a novel splicing factor kinase involved in cell survival. Nucleic Acids Res 2014; 42:3218-27. [PMID: 24369428 PMCID: PMC3950702 DOI: 10.1093/nar/gkt1307] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 11/14/2013] [Accepted: 11/25/2013] [Indexed: 12/12/2022] Open
Abstract
NEK2 is a serine/threonine kinase that promotes centrosome splitting and ensures correct chromosome segregation during the G2/M phase of the cell cycle, through phosphorylation of specific substrates. Aberrant expression and activity of NEK2 in cancer cells lead to dysregulation of the centrosome cycle and aneuploidy. Thus, a tight regulation of NEK2 function is needed during cell cycle progression. In this study, we found that NEK2 localizes in the nucleus of cancer cells derived from several tissues. In particular, NEK2 co-localizes in splicing speckles with SRSF1 and SRSF2. Moreover, NEK2 interacts with several splicing factors and phosphorylates some of them, including the oncogenic SRSF1 protein. Overexpression of NEK2 induces phosphorylation of endogenous SR proteins and affects the splicing activity of SRSF1 toward reporter minigenes and endogenous targets, independently of SRPK1. Conversely, knockdown of NEK2, like that of SRSF1, induces expression of pro-apoptotic variants from SRSF1-target genes and sensitizes cells to apoptosis. Our results identify NEK2 as a novel splicing factor kinase and suggest that part of its oncogenic activity may be ascribed to its ability to modulate alternative splicing, a key step in gene expression regulation that is frequently altered in cancer cells.
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Affiliation(s)
- Chiara Naro
- Department of Biomedicine and Prevention, University of Rome ‘Tor Vergata’, Rome, Italy, Laboratories of Neuroembryology and of Cellular and Molecular Neurobiology, Fondazione Santa Lucia IRCCS, 00143 Rome, Italy, Department of Psychology, II University of Naples, Caserta, Italy, Department of Functional Genomics and Cancer, Institut de Genetique et de Biologie Moleculaire et Cellulaire, F-67400, INSERM U964, F-67400 Illkirch, France and Department of Health Sciences, University of Rome Foro Italico, Rome, Italy
| | - Federica Barbagallo
- Department of Biomedicine and Prevention, University of Rome ‘Tor Vergata’, Rome, Italy, Laboratories of Neuroembryology and of Cellular and Molecular Neurobiology, Fondazione Santa Lucia IRCCS, 00143 Rome, Italy, Department of Psychology, II University of Naples, Caserta, Italy, Department of Functional Genomics and Cancer, Institut de Genetique et de Biologie Moleculaire et Cellulaire, F-67400, INSERM U964, F-67400 Illkirch, France and Department of Health Sciences, University of Rome Foro Italico, Rome, Italy
| | - Paolo Chieffi
- Department of Biomedicine and Prevention, University of Rome ‘Tor Vergata’, Rome, Italy, Laboratories of Neuroembryology and of Cellular and Molecular Neurobiology, Fondazione Santa Lucia IRCCS, 00143 Rome, Italy, Department of Psychology, II University of Naples, Caserta, Italy, Department of Functional Genomics and Cancer, Institut de Genetique et de Biologie Moleculaire et Cellulaire, F-67400, INSERM U964, F-67400 Illkirch, France and Department of Health Sciences, University of Rome Foro Italico, Rome, Italy
| | - Cyril F. Bourgeois
- Department of Biomedicine and Prevention, University of Rome ‘Tor Vergata’, Rome, Italy, Laboratories of Neuroembryology and of Cellular and Molecular Neurobiology, Fondazione Santa Lucia IRCCS, 00143 Rome, Italy, Department of Psychology, II University of Naples, Caserta, Italy, Department of Functional Genomics and Cancer, Institut de Genetique et de Biologie Moleculaire et Cellulaire, F-67400, INSERM U964, F-67400 Illkirch, France and Department of Health Sciences, University of Rome Foro Italico, Rome, Italy
| | - Maria Paola Paronetto
- Department of Biomedicine and Prevention, University of Rome ‘Tor Vergata’, Rome, Italy, Laboratories of Neuroembryology and of Cellular and Molecular Neurobiology, Fondazione Santa Lucia IRCCS, 00143 Rome, Italy, Department of Psychology, II University of Naples, Caserta, Italy, Department of Functional Genomics and Cancer, Institut de Genetique et de Biologie Moleculaire et Cellulaire, F-67400, INSERM U964, F-67400 Illkirch, France and Department of Health Sciences, University of Rome Foro Italico, Rome, Italy
| | - Claudio Sette
- Department of Biomedicine and Prevention, University of Rome ‘Tor Vergata’, Rome, Italy, Laboratories of Neuroembryology and of Cellular and Molecular Neurobiology, Fondazione Santa Lucia IRCCS, 00143 Rome, Italy, Department of Psychology, II University of Naples, Caserta, Italy, Department of Functional Genomics and Cancer, Institut de Genetique et de Biologie Moleculaire et Cellulaire, F-67400, INSERM U964, F-67400 Illkirch, France and Department of Health Sciences, University of Rome Foro Italico, Rome, Italy
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30
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Wong A, Zhang S, Mordue D, Wu JM, Zhang Z, Darzynkiewicz Z, Lee EYC, Lee MYWT. PDIP38 is translocated to the spliceosomes/nuclear speckles in response to UV-induced DNA damage and is required for UV-induced alternative splicing of MDM2. Cell Cycle 2013; 12:3184-93. [PMID: 23989611 DOI: 10.4161/cc.26221] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
PDIP38 (polymerase delta interacting protein 38) was originally discovered as a protein that interacts with DNA polymerase δ and PCNA. PDIP38 is present in multiple intracellular locations and is a multifunctional protein that has been implicated in several diverse cellular functions. We investigated the nuclear localization of PDIP38 in order to gain insights to its response to UV damage. PDIP38 was found to form distinct nuclear foci in response to UV irradiation in several cell lines, including HeLa S3 and A549 cells. However, these foci were not those associated with UV repair foci. Using various markers for different nuclear subcompartments, the UV-induced PDIP38 foci were identified as spliceosomes/nuclear speckles, the storage and assembly sites for mRNA splicing factors. To assess the role of PDIP38 in the regulation of splicing events, the effects of PDIP38 depletion on the UV-induced alternate splicing of MDM2 transcripts were examined by nested RT-PCR. Alternatively spliced MDM2 products were induced by UV treatment but were greatly reduced in cells expressing shRNA targeting PDIP38. These findings indicate that upon UV-induced DNA damage, PDIP38 is translocated to spliceosomes and contributes to the UV-induced alternative splicing of MDM2 transcripts. Similar results were obtained when cells were subjected to transcriptional stresses with actinomycin D or α-amanitin. Taken together, these studies show that PDIP38 is a protein regulated in a dynamic manner in response to genotoxic stress, as evidenced by its translocation to the spliceosomes. Moreover, PDIP38 is required for the induction of the alternative splicing of MDM2 in response to UV irradiation.
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Affiliation(s)
- Agnes Wong
- Department of Biochemistry and Molecular Biology; New York Medical College; Valhalla, NY USA
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31
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Naro C, Sette C. Phosphorylation-mediated regulation of alternative splicing in cancer. Int J Cell Biol 2013; 2013:151839. [PMID: 24069033 PMCID: PMC3771450 DOI: 10.1155/2013/151839] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 07/26/2013] [Indexed: 12/12/2022] Open
Abstract
Alternative splicing (AS) is one of the key processes involved in the regulation of gene expression in eukaryotic cells. AS catalyzes the removal of intronic sequences and the joining of selected exons, thus ensuring the correct processing of the primary transcript into the mature mRNA. The combinatorial nature of AS allows a great expansion of the genome coding potential, as multiple splice-variants encoding for different proteins may arise from a single gene. Splicing is mediated by a large macromolecular complex, the spliceosome, whose activity needs a fine regulation exerted by cis-acting RNA sequence elements and trans-acting RNA binding proteins (RBP). The activity of both core spliceosomal components and accessory splicing factors is modulated by their reversible phosphorylation. The kinases and phosphatases involved in these posttranslational modifications significantly contribute to AS regulation and to its integration in the complex regulative network that controls gene expression in eukaryotic cells. Herein, we will review the major canonical and noncanonical splicing factor kinases and phosphatases, focusing on those whose activity has been implicated in the aberrant splicing events that characterize neoplastic transformation.
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Affiliation(s)
- Chiara Naro
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy
- Laboratories of Neuroembryology and of Cellular and Molecular Neurobiology, Fondazione Santa Lucia IRCCS, 00143 Rome, Italy
| | - Claudio Sette
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy
- Laboratories of Neuroembryology and of Cellular and Molecular Neurobiology, Fondazione Santa Lucia IRCCS, 00143 Rome, Italy
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32
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Ji X, Zhou Y, Pandit S, Huang J, Li H, Lin CY, Xiao R, Burge CB, Fu XD. SR proteins collaborate with 7SK and promoter-associated nascent RNA to release paused polymerase. Cell 2013; 153:855-68. [PMID: 23663783 DOI: 10.1016/j.cell.2013.04.028] [Citation(s) in RCA: 256] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 03/14/2013] [Accepted: 04/15/2013] [Indexed: 10/26/2022]
Abstract
RNAP II is frequently paused near gene promoters in mammals, and its transition to productive elongation requires active recruitment of P-TEFb, a cyclin-dependent kinase for RNAP II and other key transcription elongation factors. A fraction of P-TEFb is sequestered in an inhibitory complex containing the 7SK noncoding RNA, but it has been unclear how P-TEFb is switched from the 7SK complex to RNAP II during transcription activation. We report that SRSF2 (also known as SC35, an SR-splicing factor) is part of the 7SK complex assembled at gene promoters and plays a direct role in transcription pause release. We demonstrate RNA-dependent, coordinated release of SRSF2 and P-TEFb from the 7SK complex and transcription activation via SRSF2 binding to promoter-associated nascent RNA. These findings reveal an unanticipated SR protein function, a role for promoter-proximal nascent RNA in gene activation, and an analogous mechanism to HIV Tat/TAR for activating cellular genes.
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Affiliation(s)
- Xiong Ji
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
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33
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ZRANB2 localizes to supraspliceosomes and influences the alternative splicing of multiple genes in the transcriptome. Mol Biol Rep 2013; 40:5381-95. [DOI: 10.1007/s11033-013-2637-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 05/01/2013] [Indexed: 11/27/2022]
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34
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Pandit S, Zhou Y, Shiue L, Coutinho-Mansfield G, Li H, Qiu J, Huang J, Yeo GW, Ares M, Fu XD. Genome-wide analysis reveals SR protein cooperation and competition in regulated splicing. Mol Cell 2013; 50:223-35. [PMID: 23562324 DOI: 10.1016/j.molcel.2013.03.001] [Citation(s) in RCA: 234] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 01/02/2013] [Accepted: 02/25/2013] [Indexed: 12/12/2022]
Abstract
SR proteins are well-characterized RNA binding proteins that promote exon inclusion by binding to exonic splicing enhancers (ESEs). However, it has been unclear whether regulatory rules deduced on model genes apply generally to activities of SR proteins in the cell. Here, we report global analyses of two prototypical SR proteins, SRSF1 (SF2/ASF) and SRSF2 (SC35), using splicing-sensitive arrays and CLIP-seq on mouse embryo fibroblasts (MEFs). Unexpectedly, we find that these SR proteins promote both inclusion and skipping of exons in vivo, but their binding patterns do not explain such opposite responses. Further analyses reveal that loss of one SR protein is accompanied by coordinated loss or compensatory gain in the interaction of other SR proteins at the affected exons. Therefore, specific effects on regulated splicing by one SR protein actually depend on a complex set of relationships with multiple other SR proteins in mammalian genomes.
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Affiliation(s)
- Shatakshi Pandit
- Department of Cellular and Molecular Medicine and Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093-0651, USA
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35
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Regulation of splicing by SR proteins and SR protein-specific kinases. Chromosoma 2013; 122:191-207. [PMID: 23525660 DOI: 10.1007/s00412-013-0407-z] [Citation(s) in RCA: 320] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 03/04/2013] [Accepted: 03/06/2013] [Indexed: 12/21/2022]
Abstract
Genomic sequencing reveals similar but limited numbers of protein-coding genes in different genomes, which begs the question of how organismal diversities are generated. Alternative pre-mRNA splicing, a widespread phenomenon in higher eukaryotic genomes, is thought to provide a mechanism to increase the complexity of the proteome and introduce additional layers for regulating gene expression in different cell types and during development. Among a large number of factors implicated in the splicing regulation are the SR protein family of splicing factors and SR protein-specific kinases. Here, we summarize the rules for SR proteins to function as splicing regulators, which depend on where they bind in exons versus intronic regions, on alternative exons versus flanking competing exons, and on cooperative as well as competitive binding between different SR protein family members on many of those locations. We review the importance of cycles of SR protein phosphorylation/dephosphorylation in the splicing reaction with emphasis on the recent molecular insight into the role of SR protein phosphorylation in early steps of spliceosome assembly. Finally, we highlight recent discoveries of SR protein-specific kinases in transducing growth signals to regulate alternative splicing in the nucleus and the connection of both SR proteins and SR protein kinases to human diseases, particularly cancer.
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36
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Edmond V, Merdzhanova G, Gout S, Brambilla E, Gazzeri S, Eymin B. A new function of the splicing factor SRSF2 in the control of E2F1-mediated cell cycle progression in neuroendocrine lung tumors. Cell Cycle 2013; 12:1267-78. [PMID: 23518498 DOI: 10.4161/cc.24363] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The transcription factor E2F1 belongs to the E2F family and plays a crucial role during cell cycle progression and apoptosis. Ser/Arg-Rich (SR) proteins are a family of RNA-binding phosphoproteins that control both constitutive and alternative pre-mRNA splicing events. We previously identified the SR protein SRSF2 as a new transcriptional target of E2F1 and demonstrated that both proteins cooperate to induce apoptosis in non-small cell lung carcinoma. In this study, we postulated that SRSF2 is also involved in the proliferative functions of E2F1. Using IHC, we first demonstrate that SRSF2 and its phosphorylated form (P-SRSF2) are overexpressed in neuroendocrine lung tumors that are highly proliferative tumors expressing high levels of E2F1. Importantly, we show a direct correlation between cyclin E, an E2F1-target gene controlling S phase, and P-SRSF2 proteins levels (p = 0.0083), suggesting a role of SRSF2 in E2F1-mediated cellular proliferation. Accordingly, using neuroendocrine lung carcinoma cell lines, we demonstrate that SRSF2 is a cell cycle-regulated protein involved in entry and progression into S phase. We also provide evidence that SRSF2 interacts with E2F1 and stimulates its transcriptional control of cell cycle target genes such as cyclin E. Finally, we show that inhibition of AKT signaling pathway prevents SRSF2 phosphorylation and activity toward E2F1 transcriptional function. Taken together, these results identify a new role of SRSF2 in the control of cell cycle progression and reinforce the functional link between SRSF2 and E2F1 proteins.
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Affiliation(s)
- Valerie Edmond
- INSERM, U823, Equipe 2 Bases Moléculaires de la Progression des Cancers du Poumon, Grenoble, France
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37
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Müller-McNicoll M, Neugebauer KM. How cells get the message: dynamic assembly and function of mRNA-protein complexes. Nat Rev Genet 2013; 14:275-87. [PMID: 23478349 DOI: 10.1038/nrg3434] [Citation(s) in RCA: 299] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
mRNA is packaged into ribonucleoprotein particles called mRNPs. A multitude of RNA-binding proteins as well as a host of associated proteins participate in the fate of mRNA from transcription and processing in the nucleus to translation and decay in the cytoplasm. Methodological innovations in cell biology and genome-wide high-throughput approaches have revealed an unexpected diversity of mRNA-associated proteins and unforeseen interconnections between mRNA-processing steps. Recent insights into mRNP formation in vivo have also highlighted the importance of mRNP packaging, which can sort RNAs on the basis of their length and determine mRNA fate through alternative mRNP assembly, processing and export pathways.
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Affiliation(s)
- Michaela Müller-McNicoll
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
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38
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Breig O, Baklouti F. Proteasome-mediated proteolysis of SRSF5 splicing factor intriguingly co-occurs with SRSF5 mRNA upregulation during late erythroid differentiation. PLoS One 2013; 8:e59137. [PMID: 23536862 PMCID: PMC3594168 DOI: 10.1371/journal.pone.0059137] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 02/13/2013] [Indexed: 01/08/2023] Open
Abstract
SR proteins exhibit diverse functions ranging from their role in constitutive and alternative splicing, to virtually all aspects of mRNA metabolism. These findings have attracted growing interest in deciphering the regulatory mechanisms that control the tissue-specific expression of these SR proteins. In this study, we show that SRSF5 protein decreases drastically during erythroid cell differentiation, contrasting with a concomitant upregulation of SRSF5 mRNA level. Proteasome chemical inhibition provided strong evidence that endogenous SRSF5 protein, as well as protein deriving from stably transfected SRSF5 cDNA, are both targeted to proteolysis as the cells undergo terminal differentiation. Consistently, functional experiments show that overexpression of SRSF5 enhances a specific endogenous pre-mRNA splicing event in proliferating cells, but not in differentiating cells, due to proteasome-mediated targeting of both endogenous and transfection-derived SRSF5. Further investigation of the relationship between SRSF5 structure and its post-translation regulation and function, suggested that the RNA recognition motifs of SRSF5 are sufficient to activate pre-mRNA splicing, whereas proteasome-mediated proteolysis of SRSF5 requires the presence of the C-terminal RS domain of the protein. Phosphorylation of SR proteins is a key post-translation regulation that promotes their activity and subcellular availability. We here show that inhibition of the CDC2-like kinase (CLK) family and mutation of the AKT phosphorylation site Ser86 on SRSF5, have no effect on SRSF5 stability. We reasoned that at least AKT and CLK signaling pathways are not involved in proteasome-induced turnover of SRSF5 during late erythroid development.
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Affiliation(s)
- Osman Breig
- "mRNA Metabolism in Normal and Pathological Cells"; Centre de Génétique et de Physiologie Moléculaire et Cellulaire, CNRS UMR, Université Lyon 1, Villeurbanne, France
| | - Faouzi Baklouti
- "mRNA Metabolism in Normal and Pathological Cells"; Centre de Génétique et de Physiologie Moléculaire et Cellulaire, CNRS UMR, Université Lyon 1, Villeurbanne, France
- * E-mail:
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39
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Sugaya K, Ishihara Y, Sugaya K, Inoue S. Characterization of the role of Smu1 in nuclear localization of splicing factors in the mammalian temperature-sensitive mutant. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/ajmb.2013.31005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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40
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Odunsi K, Mhawech-Fauceglia P, Andrews C, Beck A, Amuwo O, Lele S, Black JD, Huang RY. Elevated expression of the serine-arginine protein kinase 1 gene in ovarian cancer and its role in Cisplatin cytotoxicity in vitro. PLoS One 2012; 7:e51030. [PMID: 23236423 PMCID: PMC3517604 DOI: 10.1371/journal.pone.0051030] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 10/23/2012] [Indexed: 11/18/2022] Open
Abstract
Alternatively spliced variants of several oncogenes and tumor suppressors have been shown to be important for their tumorigenicity. In the present study we have tested whether serine-arginine protein kinase 1 (SRPK1), a major regulator of splicing factors, is involved in ovarian cancer progression and plays a role in chemo-sensitivity. By Western blot analyses, SRPK1 protein was found to be overexpressed in 4 out of 6 ovarian cancer cell lines as compared with an immortalized ovarian surface epithelial cell line; and in 55% of ovarian tumor samples as compared with non-neoplastic ovarian tissue samples. Reduction of SRPK1 expression using small interfering RNA (siRNA) encoding small hairpin RNA in ovarian cancer cells led to (i) reduced cell proliferation rate, slower cell cycle progression and compromised anchorage-independent growth and migration ability in vitro, (ii) decreased level of phosphorylation of multiple serine-arginine proteins, and P44/42MAPK and AKT proteins, and (iii) enhanced sensitivity to cisplatin. Together, these results suggest that elevated SRPK1 expression may play a role in ovarian tumorigenesis and SRPK1 may be a potential target for ovarian cancer therapy.
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Affiliation(s)
- Kunle Odunsi
- Department of Gynecologic Oncology, Roswell Park Cancer Institute, Buffalo, New York, United States of America
- Department of Immunology, Roswell Park Cancer Institute, Buffalo, New York, United States of America
- Center for Immunotherapy, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Paulette Mhawech-Fauceglia
- Department of Pathology and Laboratory Medicine, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Christopher Andrews
- Department of Biostatistics, State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Amy Beck
- Center for Immunotherapy, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Olajumoke Amuwo
- Department of Gynecologic Oncology, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Shashikant Lele
- Department of Gynecologic Oncology, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Jennifer D. Black
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Ruea-Yea Huang
- Department of Gynecologic Oncology, Roswell Park Cancer Institute, Buffalo, New York, United States of America
- * E-mail:
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41
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Tripathi V, Song DY, Zong X, Shevtsov SP, Hearn S, Fu XD, Dundr M, Prasanth KV. SRSF1 regulates the assembly of pre-mRNA processing factors in nuclear speckles. Mol Biol Cell 2012; 23:3694-706. [PMID: 22855529 PMCID: PMC3442416 DOI: 10.1091/mbc.e12-03-0206] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
SRSF1 splicing factor and nuclear-localized MALAT1 RNA influence the assembly of nuclear speckles. Depletion of SRSF1 compromises the association of splicing factors to nuclear speckles and influences the levels of other SR proteins. SRSF1 regulates RNA polymerase II–mediated transcription. The mammalian cell nucleus is compartmentalized into nonmembranous subnuclear domains that regulate key nuclear functions. Nuclear speckles are subnuclear domains that contain pre-mRNA processing factors and noncoding RNAs. Many of the nuclear speckle constituents work in concert to coordinate multiple steps of gene expression, including transcription, pre-mRNA processing and mRNA transport. The mechanism that regulates the formation and maintenance of nuclear speckles in the interphase nucleus is poorly understood. In the present study, we provide evidence for the involvement of nuclear speckle resident proteins and RNA components in the organization of nuclear speckles. SR-family splicing factors and their binding partner, long noncoding metastasis-associated lung adenocarcinoma transcript 1 RNA, can nucleate the assembly of nuclear speckles in the interphase nucleus. Depletion of SRSF1 in human cells compromises the association of splicing factors to nuclear speckles and influences the levels and activity of other SR proteins. Furthermore, on a stably integrated reporter gene locus, we demonstrate the role of SRSF1 in RNA polymerase II–mediated transcription. Our results suggest that SR proteins mediate the assembly of nuclear speckles and regulate gene expression by influencing both transcriptional and posttranscriptional activities within the cell nucleus.
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Affiliation(s)
- Vidisha Tripathi
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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42
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RBM20, a gene for hereditary cardiomyopathy, regulates titin splicing. Nat Med 2012; 18:766-73. [PMID: 22466703 DOI: 10.1038/nm.2693] [Citation(s) in RCA: 405] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 01/31/2012] [Indexed: 01/15/2023]
Abstract
Alternative splicing has a major role in cardiac adaptive responses, as exemplified by the isoform switch of the sarcomeric protein titin, which adjusts ventricular filling. By positional cloning using a previously characterized rat strain with altered titin mRNA splicing, we identified a loss-of-function mutation in the gene encoding RNA binding motif protein 20 (Rbm20) as the underlying cause of pathological titin isoform expression. The phenotype of Rbm20-deficient rats resembled the pathology seen in individuals with dilated cardiomyopathy caused by RBM20 mutations. Deep sequencing of the human and rat cardiac transcriptome revealed an RBM20-dependent regulation of alternative splicing. In addition to titin (TTN), we identified a set of 30 genes with conserved splicing regulation between humans and rats. This network is enriched for genes that have previously been linked to cardiomyopathy, ion homeostasis and sarcomere biology. Our studies emphasize the key role of post-transcriptional regulation in cardiac function and provide mechanistic insights into the pathogenesis of human heart failure.
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43
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Shikata H, Shibata M, Ushijima T, Nakashima M, Kong SG, Matsuoka K, Lin C, Matsushita T. The RS domain of Arabidopsis splicing factor RRC1 is required for phytochrome B signal transduction. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 70:727-38. [PMID: 22324426 DOI: 10.1111/j.1365-313x.2012.04937.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Plants monitor the light environment through informational photoreceptors that include phytochromes. In seedling de-etiolation, phytochrome B (phyB), which is the most important member of the phytochrome family, interacts with transcription factors to regulate gene expression and transduce light signals. In this study, we identified rrc1 (reduced red-light responses in cry1cry2 background 1), an Arabidopsis mutant that is impaired in phyB-mediated light responses. A genetic analysis demonstrated that RRC1 affected light signaling in a phyB-dependent manner. RRC1 encodes an ortholog of the human potential splicing factor SR140. The RRC1 polypeptide contains a C-terminal arginine/serine-rich (RS) domain that is important for the regulation of alternative splicing. Although the complete loss of RRC1 caused pleiotropic developmental abnormalities, the deletion of the RS domain specifically reduced phyB signaling and caused aberrant alternative splicing of several SR protein genes. Moreover, semi-quantitative RT-PCR analysis revealed that the alternative splicing patterns of some of the SR protein genes were altered in a red-light-dependent manner, and that these responses were reduced in both phyB and rrc1 mutants. These findings suggest that the regulation of alternative splicing by the RS domain of RRC1 plays an important role in phyB signal transduction.
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MESH Headings
- Active Transport, Cell Nucleus
- Alternative Splicing
- Arabidopsis/genetics
- Arabidopsis/metabolism
- Arabidopsis/radiation effects
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- Cloning, Molecular
- Color
- Gene Expression Regulation, Plant
- Genes, Plant
- Genetic Pleiotropy
- Light
- Phytochrome B/genetics
- Phytochrome B/metabolism
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/metabolism
- Plants, Genetically Modified/radiation effects
- Plasmids/genetics
- Plasmids/metabolism
- Protein Structure, Tertiary
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Deletion
- Signal Transduction
- Transformation, Genetic
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Affiliation(s)
- Hiromasa Shikata
- Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan
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Hallgren O, Malmström J, Malmström L, Andersson-Sjöland A, Wildt M, Tufvesson E, Juhasz P, Marko-Varga G, Westergren-Thorsson G. Splicosomal and serine and arginine-rich splicing factors as targets for TGF-β. FIBROGENESIS & TISSUE REPAIR 2012; 5:6. [PMID: 22541002 PMCID: PMC3472233 DOI: 10.1186/1755-1536-5-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 04/28/2012] [Indexed: 11/29/2022]
Abstract
Background Transforming growth factor-β1 (TGF-β1) is a potent regulator of cell growth and differentiation. TGF-β1 has been shown to be a key player in tissue remodeling processes in a number of disease states by inducing expression of extracellular matrix proteins. In this study a quantitative proteomic analysis was undertaken to investigate if TGF-β1 contributes to tissue remodeling by mediating mRNA splicing and production of alternative isoforms of proteins. Methodology/Principal findings The expression of proteins involved in mRNA splicing from TGF-β1-stimulated lung fibroblasts was compared to non-stimulated cells by employing isotope coded affinity tag (ICATTM) reagent labeling and tandem mass spectrometry. A total of 1733 proteins were identified and quantified with a relative standard deviation of 11% +/− 8 from enriched nuclear fractions. Seventy-six of these proteins were associated with mRNA splicing, including 22 proteins involved in splice site selection. In addition, TGF-β1 was observed to alter the relative expression of splicing proteins that may be important for alternative splicing of fibronectin. Specifically, TGF-β1 significantly induced expression of SRp20, and reduced the expression of SRp30C, which has been suggested to be a prerequisite for generation of alternatively spliced fibronectin. The induction of SRp20 was further confirmed by western blot and immunofluorescence. Conclusions The results show that TGF-β1 induces the expression of proteins involved in mRNA splicing and RNA processing in human lung fibroblasts. This may have an impact on the production of alternative isoforms of matrix proteins and can therefore be an important factor in tissue remodeling and disease progression.
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Affiliation(s)
- Oskar Hallgren
- Department of Experimental Medical Science, Lund University, Lund, Sweden.
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Saitoh N, Sakamoto C, Hagiwara M, Agredano-Moreno LT, Jiménez-García LF, Nakao M. The distribution of phosphorylated SR proteins and alternative splicing are regulated by RANBP2. Mol Biol Cell 2012; 23:1115-28. [PMID: 22262462 PMCID: PMC3302738 DOI: 10.1091/mbc.e11-09-0783] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
SR splicing factors are distributed in the speckled pattern in the nucleus. Alternative pre-mRNA splicing is regulated through nuclear distribution of phosphorylated SR splicing factors, which is specifically regulated by the RANBP2 system in mammalian cell lines, as well as in mouse tissues. The mammalian cell nucleus is functionally compartmentalized into various substructures. Nuclear speckles, also known as interchromatin granule clusters, are enriched with SR splicing factors and are implicated in gene expression. Here we report that nuclear speckle formation is developmentally regulated; in certain cases phosphorylated SR proteins are absent from the nucleus and are instead localized at granular structures in the cytoplasm. To investigate how the nuclear architecture is formed, we performed a phenotypic screen of HeLa cells treated with a series of small interfering RNAs. Depletion of Ran-binding protein 2 induced cytoplasmic intermediates of nuclear speckles in G1 phase. Detailed analyses of these structures suggested that a late step in the sequential nuclear entry of mitotic interchromatin granule components was disrupted and that phosphorylated SR proteins were sequestered in an SR protein kinase–dependent manner. As a result, the cells had an imbalanced subcellular distribution of phosphorylated and hypophosphorylated SR proteins, which affected alternative splicing patterns. This study demonstrates that the speckled distribution of phosphorylated pre-mRNA processing factors is regulated by the nucleocytoplasmic transport system in mammalian cells and that it is important for alternative splicing.
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Affiliation(s)
- Noriko Saitoh
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811, Japan.
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Eblen ST. Regulation of chemoresistance via alternative messenger RNA splicing. Biochem Pharmacol 2012; 83:1063-72. [PMID: 22248731 DOI: 10.1016/j.bcp.2011.12.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 12/29/2011] [Accepted: 12/29/2011] [Indexed: 12/17/2022]
Abstract
The acquisition of resistance to chemotherapy is a significant problem in the treatment of cancer, greatly increasing patient morbidity and mortality. Tumors are often sensitive to chemotherapy upon initial treatment, but repeated treatments can select for those cells that were able to survive initial therapy and have acquired cellular mechanisms to enhance their resistance to subsequent chemotherapy treatment. Many cellular mechanisms of drug resistance have been identified, most of which result from changes in gene and protein expression. While changes at the transcriptional level have been duly noted, it is primarily the post-transcriptional processing of pre-mRNA into mature mRNA that regulates the composition of the proteome and it is the proteome that actually regulates the cell's response to chemotherapeutic insult, inducing cell survival or death. During pre-mRNA processing, intronic non-protein-coding sequences are removed and protein-coding exons are spliced to form a continuous template for protein translation. Alternative splicing involves the differential inclusion or exclusion of exonic sequences into the mature transcript, generating different mRNA templates for protein production. This regulatory mechanism enables the potential to produce many different protein isoforms from the same gene. In this review I will explain the mechanism of alternative pre-mRNA splicing and look at some specific examples of how splicing factors, splicing factor kinases and alternative splicing of specific pre-mRNAs from genes have been shown to contribute to acquisition of the drug resistant phenotype.
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Affiliation(s)
- Scott T Eblen
- Department of Cell and Molecular Pharmacology, Medical University of South Carolina, Charleston, 29425, USA.
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Ninomiya K, Kataoka N, Hagiwara M. Stress-responsive maturation of Clk1/4 pre-mRNAs promotes phosphorylation of SR splicing factor. ACTA ACUST UNITED AC 2011; 195:27-40. [PMID: 21949414 PMCID: PMC3187705 DOI: 10.1083/jcb.201107093] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A nuclear pool of partially spliced Clk1/4 pre-mRNAs matures in response to stress and induces SR protein phosphorylation and activation. It has been assumed that premessenger ribonucleic acids (RNAs; pre-mRNAs) are spliced cotranscriptionally in the process of gene expression. However, in this paper, we report that splicing of Clk1/4 mRNAs is suspended in tissues and cultured cells and that intermediate forms retaining specific introns are abundantly pooled in the nucleus. Administration of the Cdc2-like kinase–specific inhibitor TG003 increased the level of Clk1/4 mature mRNAs by promoting splicing of the intron-retaining RNAs. Under stress conditions, splicing of general pre-mRNAs was inhibited by dephosphorylation of SR splicing factors, but exposure to stresses, such as heat shock and osmotic stress, promoted the maturation of Clk1/4 mRNAs. Clk1/4 proteins translated after heat shock catalyzed rephosphorylation of SR proteins, especially SRSF4 and SRSF10. These findings suggest that Clk1/4 expression induced by stress-responsive splicing serves to maintain the phosphorylation state of SR proteins.
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Affiliation(s)
- Kensuke Ninomiya
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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Sun D, Novotny M, Bulek K, Liu C, Li X, Hamilton T. Treatment with IL-17 prolongs the half-life of chemokine CXCL1 mRNA via the adaptor TRAF5 and the splicing-regulatory factor SF2 (ASF). Nat Immunol 2011; 12:853-60. [PMID: 21822258 PMCID: PMC3597344 DOI: 10.1038/ni.2081] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 06/30/2011] [Indexed: 12/21/2022]
Abstract
Interleukin 17 (IL-17) promotes the expression of chemokines and cytokines via the induction of gene transcription and post-transcriptional stabilization of mRNA. We show here that IL-17 enhanced the stability of chemokine CXCL1 mRNA and other mRNAs through a pathway that involved the adaptor Act1, the adaptors TRAF2 or TRAF5 and the splicing factor SF2 (also known as alternative splicing factor (ASF)). TRAF2 and TRAF5 were necessary for IL-17 to signal the stabilization of CXCL1 mRNA. Furthermore, IL-17 promoted the formation of complexes of TRAF5-TRAF2, Act1 and SF2 (ASF). Overexpression of SF2 (ASF) shortened the half-life of CXCL1 mRNA, whereas depletion of SF2 (ASF) prolonged it. SF2 (ASF) bound chemokine mRNA in unstimulated cells, whereas the SF2 (ASF)-mRNA interaction was much lower after stimulation with IL-17. Our findings define an IL-17-induced signaling pathway that links to the stabilization of selected mRNA species through Act1, TRAF2-TRAF5 and the RNA-binding protein SF2 (ASF).
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Affiliation(s)
- Dongxu Sun
- Department of Immunology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA
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Interaction between the RNA binding domains of Ser-Arg splicing factor 1 and U1-70K snRNP protein determines early spliceosome assembly. Proc Natl Acad Sci U S A 2011; 108:8233-8. [PMID: 21536904 DOI: 10.1073/pnas.1017700108] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has been widely accepted that the early spliceosome assembly begins with U1 small nuclear ribonucleoprotein (U1 snRNP) binding to the 5' splice site (5'SS), which is assisted by the Ser/Arg (SR)-rich proteins in mammalian cells. In this process, the RS domain of SR proteins is thought to directly interact with the RS motif of U1-70K, which is subject to regulation by RS domain phosphorylation. Here we report that the early spliceosome assembly event is mediated by the RNA recognition domains (RRM) of serine/arginine-rich splicing factor 1 (SRSF1), which bridges the RRM of U1-70K to pre-mRNA by using the surface opposite to the RNA binding site. Specific mutation in the RRM of SRSF1 that disrupted the RRM-RRM interaction also inhibits the formation of spliceosomal E complex and splicing. We further demonstrate that the hypo-phosphorylated RS domain of SRSF1 interacts with its own RRM, thus competing with U1-70K binding, whereas the hyper-phosphorylated RS domain permits the formation of a ternary complex containing ESE, an SR protein, and U1 snRNP. Therefore, phosphorylation of the RS domain in SRSF1 appears to induce a key molecular switch from intra- to intermolecular interactions, suggesting a plausible mechanism for the documented requirement for the phosphorylation/dephosphorylation cycle during pre-mRNA splicing.
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Paronetto MP, Messina V, Barchi M, Geremia R, Richard S, Sette C. Sam68 marks the transcriptionally active stages of spermatogenesis and modulates alternative splicing in male germ cells. Nucleic Acids Res 2011; 39:4961-74. [PMID: 21355037 PMCID: PMC3130265 DOI: 10.1093/nar/gkr085] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Sam68 plays an essential role in mouse spermatogenesis and male fertility. Herein, we report an interaction between Sam68 and the phosphorylated forms of the RNA polymerase II (RNAPII) in meiotic spermatocytes. RNase treatment decreased but did not abolish the interaction, consistently with in vitro binding of RNAPII to the Sam68 carboxyl-terminal region. Sam68 retention in the spermatocyte nucleus was dependent on the integrity of cellular RNAs, suggesting that the protein is recruited to transcriptionally active chromatin. Mouse knockout models characterized by stage-specific arrest of spermatogenesis and staining with the phosphorylated form of RNAPII documented that Sam68 expression is confined to the transcriptionally active stages of spermatogenesis. Furthermore, Sam68 associates with splicing regulators in germ cells and we report that alternative splicing of Sgce exon 8 is regulated in a Sam68-dependent manner during spermatogenesis. RNA and chromatin crosslink immunoprecipitation experiments showed that Sam68 binds in vivo to sequences surrounding the intron 7/exon 8 boundary, thereby affecting the recruitment of the phosphorylated RNAPII and of the general splicing factor U2AF65. These results suggest that Sam68 regulates alternative splicing at transcriptionally active sites in differentiating germ cells and provide new insights into the regulation of Sam68 expression during spermatogenesis.
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Affiliation(s)
- Maria Paola Paronetto
- Department of Public Health and Cell Biology, Section of Anatomy, University of Rome, 00133 Rome, Italy
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