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Olazabal-Herrero A, He B, Kwon Y, Gupta AK, Dutta A, Huang Y, Boddu P, Liang Z, Liang F, Teng Y, Lan L, Chen X, Pei H, Pillai MM, Sung P, Kupfer GM. The FANCI/FANCD2 complex links DNA damage response to R-loop regulation through SRSF1-mediated mRNA export. Cell Rep 2024; 43:113610. [PMID: 38165804 PMCID: PMC10865995 DOI: 10.1016/j.celrep.2023.113610] [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: 09/30/2022] [Revised: 11/21/2023] [Accepted: 12/05/2023] [Indexed: 01/04/2024] Open
Abstract
Fanconi anemia (FA) is characterized by congenital abnormalities, bone marrow failure, and cancer susceptibility. The central FA protein complex FANCI/FANCD2 (ID2) is activated by monoubiquitination and recruits DNA repair proteins for interstrand crosslink (ICL) repair and replication fork protection. Defects in the FA pathway lead to R-loop accumulation, which contributes to genomic instability. Here, we report that the splicing factor SRSF1 and FANCD2 interact physically and act together to suppress R-loop formation via mRNA export regulation. We show that SRSF1 stimulates FANCD2 monoubiquitination in an RNA-dependent fashion. In turn, FANCD2 monoubiquitination proves crucial for the assembly of the SRSF1-NXF1 nuclear export complex and mRNA export. Importantly, several SRSF1 cancer-associated mutants fail to interact with FANCD2, leading to inefficient FANCD2 monoubiquitination, decreased mRNA export, and R-loop accumulation. We propose a model wherein SRSF1 and FANCD2 interaction links DNA damage response to the avoidance of pathogenic R-loops via regulation of mRNA export.
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Affiliation(s)
- Anne Olazabal-Herrero
- Department of Oncology and Pediatrics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA; Section of Hematology, Department of Internal Medicine, Yale School of Medicine and Yale Cancer Center, New Haven, CT 06511, USA
| | - Boxue He
- Department of Biochemistry and Structural Biology, Greehey Children's Cancer Research Institute, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; Department of Thoracic Surgery, Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Youngho Kwon
- Department of Biochemistry and Structural Biology, Greehey Children's Cancer Research Institute, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Abhishek K Gupta
- Section of Hematology, Department of Internal Medicine, Yale School of Medicine and Yale Cancer Center, New Haven, CT 06511, USA
| | - Arijit Dutta
- Department of Biochemistry and Structural Biology, Greehey Children's Cancer Research Institute, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Yuxin Huang
- Department of Biochemistry and Structural Biology, Greehey Children's Cancer Research Institute, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Prajwal Boddu
- Section of Hematology, Department of Internal Medicine, Yale School of Medicine and Yale Cancer Center, New Haven, CT 06511, USA
| | - Zhuobin Liang
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Fengshan Liang
- Department of Oncology and Pediatrics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA; Section of Hematology, Department of Internal Medicine, Yale School of Medicine and Yale Cancer Center, New Haven, CT 06511, USA
| | - Yaqun Teng
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02129, USA; Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Li Lan
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02129, USA; Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Xiaoyong Chen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Huadong Pei
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA
| | - Manoj M Pillai
- Section of Hematology, Department of Internal Medicine, Yale School of Medicine and Yale Cancer Center, New Haven, CT 06511, USA
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, Greehey Children's Cancer Research Institute, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
| | - Gary M Kupfer
- Department of Oncology and Pediatrics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA.
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2
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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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3
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Shi W, Yang J, Chen D, Yin C, Zhang H, Xu X, Pan X, Wang R, Fei L, Li M, Qi L, Bhadauria V, Liu J, Peng YL. The rice blast fungus SR protein 1 regulates alternative splicing with unique mechanisms. PLoS Pathog 2022; 18:e1011036. [PMID: 36480554 PMCID: PMC9767378 DOI: 10.1371/journal.ppat.1011036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 12/20/2022] [Accepted: 11/30/2022] [Indexed: 12/13/2022] Open
Abstract
Serine/arginine-rich (SR) proteins are well known as splicing factors in humans, model animals and plants. However, they are largely unknown in regulating pre-mRNA splicing of filamentous fungi. Here we report that the SR protein MoSrp1 enhances and suppresses alternative splicing in a model fungal plant pathogen Magnaporthe oryzae. Deletion of MoSRP1 caused multiple defects, including reduced virulence and thousands of aberrant alternative splicing events in mycelia, most of which were suppressed or enhanced intron splicing. A GUAG consensus bound by MoSrp1 was identified in more than 94% of the intron or/and proximate exons having the aberrant splicing. The dual functions of regulating alternative splicing of MoSrp1 were exemplified in enhancing and suppressing the consensus-mediated efficient splicing of the introns in MoATF1 and MoMTP1, respectively, which both were important for mycelial growth, conidiation, and virulence. Interestingly, MoSrp1 had a conserved sumoylation site that was essential to nuclear localization and enhancing GUAG binding. Further, we showed that MoSrp1 interacted with a splicing factor and two components of the exon-joining complex via its N-terminal RNA recognition domain, which was required to regulate mycelial growth, development and virulence. In contrast, the C-terminus was important only for virulence and stress responses but not for mycelial growth and development. In addition, only orthologues from Pezizomycotina species could completely rescue defects of the deletion mutants. This study reveals that the fungal conserved SR protein Srp1 regulates alternative splicing in a unique manner.
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Affiliation(s)
- Wei Shi
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jun Yang
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Department of Plant Biosecurity, College of Plant Protection, China Agricultural University, Beijing, China
| | - Deng Chen
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Changfa Yin
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Huixia Zhang
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Department of Plant Biosecurity, College of Plant Protection, China Agricultural University, Beijing, China
| | - Xiaozhou Xu
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Xiao Pan
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Department of Plant Biosecurity, College of Plant Protection, China Agricultural University, Beijing, China
| | - Ruijin Wang
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Department of Plant Biosecurity, College of Plant Protection, China Agricultural University, Beijing, China
| | - Liwang Fei
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Mengfei Li
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Linlu Qi
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Vijai Bhadauria
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Junfeng Liu
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - You-Liang Peng
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China
- MARA Key Laboratory of Pest Monitoring and Green Management, Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- * E-mail:
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4
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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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5
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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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6
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Kim CH, Park SM, Lee SJ, Kim YD, Jang SH, Woo SM, Kwon TK, Park ZY, Chung IJ, Kim HR, Jun CD. NSrp70 is a lymphocyte-essential splicing factor that controls thymocyte development. Nucleic Acids Res 2021; 49:5760-5778. [PMID: 34037780 PMCID: PMC8191771 DOI: 10.1093/nar/gkab389] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 04/04/2021] [Accepted: 04/30/2021] [Indexed: 11/21/2022] Open
Abstract
Alternative pre-mRNA splicing is a critical step to generate multiple transcripts, thereby dramatically enlarging the proteomic diversity. Thus, a common feature of most alternative splicing factor knockout models is lethality. However, little is known about lineage-specific alternative splicing regulators in a physiological setting. Here, we report that NSrp70 is selectively expressed in developing thymocytes, highest at the double-positive (DP) stage. Global splicing and transcriptional profiling revealed that NSrp70 regulates the cell cycle and survival of thymocytes by controlling the alternative processing of various RNA splicing factors, including the oncogenic splicing factor SRSF1. A conditional-knockout of Nsrp1 (NSrp70-cKO) using CD4Cre developed severe defects in T cell maturation to single-positive thymocytes, due to insufficient T cell receptor (TCR) signaling and uncontrolled cell growth and death. Mice displayed severe peripheral lymphopenia and could not optimally control tumor growth. This study establishes a model to address the function of lymphoid-lineage-specific alternative splicing factor NSrp70 in a thymic T cell developmental pathway.
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Affiliation(s)
- Chang-Hyun Kim
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - Sang-Moo Park
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - Sun-Jae Lee
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - Young-Dae Kim
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - Se-Hwan Jang
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - Seon-Min Woo
- Department of Immunology, School of Medicine, Keimyung University, Daegu 42601, Korea
| | - Taeg-Kyu Kwon
- Department of Immunology, School of Medicine, Keimyung University, Daegu 42601, Korea
| | - Zee-Yong Park
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - Ik-Joo Chung
- Department of Hematology-Oncology, Immunotherapy Innovation Center, Chonnam National University Medical School, Hwasun 58128, Korea
| | - Hye-Ran Kim
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - Chang-Duk Jun
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
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7
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Wagner RE, Frye M. Noncanonical functions of the serine-arginine-rich splicing factor (SR) family of proteins in development and disease. Bioessays 2021; 43:e2000242. [PMID: 33554347 DOI: 10.1002/bies.202000242] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 12/19/2022]
Abstract
Members of the serine/arginine (SR)-rich protein family of splicing factors play versatile roles in RNA processing steps and are often essential for normal development. Dynamic changes in RNA processing and turnover allow fast cellular adaptions to a changing microenvironment and thereby closely cooperate with transcription factor networks that establish cell identity within tissues. SR proteins play fundamental roles in the processing of pre-mRNAs by regulating constitutive and alternative splicing. More recently, SR proteins have also been implicated in other aspects of RNA metabolism such as mRNA stability, transport and translation. The- emerging noncanonical functions highlight the multifaceted functions of these SR proteins and identify them as important coordinators of gene expression programmes. Accordingly, most SR proteins are essential for normal cell function and their misregulation contributes to human diseases such as cancer.
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Affiliation(s)
- Rebecca E Wagner
- German Cancer Research Center - Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Michaela Frye
- German Cancer Research Center - Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
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8
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Singh AK, Tamrakar A, Jaiswal A, Kanayama N, Kodgire P. SRSF1-3, a splicing and somatic hypermutation regulator, controls transcription of IgV genes via chromatin regulators SATB2, UBN1 and histone variant H3.3. Mol Immunol 2020; 119:69-82. [DOI: 10.1016/j.molimm.2020.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/01/2020] [Accepted: 01/11/2020] [Indexed: 12/21/2022]
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9
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Splicing regulator SRSF1-3 that controls somatic hypermutation of IgV genes interacts with topoisomerase 1 and AID. Mol Immunol 2019; 116:63-72. [PMID: 31622795 DOI: 10.1016/j.molimm.2019.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/24/2019] [Accepted: 10/01/2019] [Indexed: 01/27/2023]
Abstract
Somatic hypermutation (SHM) of Ig genes is initiated by activation-induced cytidine deaminase (AID) and requires target gene transcription. A splice isoform of SRSF1, SRSF1-3, is necessary for AID-dependent SHM of IgV genes. Nevertheless, its exact molecular mechanism of action in SHM remains unknown. Our in silico studies show that, unlike SRSF1, SRSF1-3 lacks a strong nuclear localization domain. We show that the absence of RS domain in SRSF1-3 affects its nuclear localization, as compared to SRSF1. Consequently, SRSF1-3 is predominantly present in the cytoplasm. Remarkably, co-immunoprecipitation studies showed that SRSF1-3 interacts with Topoisomerase 1 (TOP1), a crucial regulator of SHM that assists in generating ssDNA for AID activity. Moreover, the immunofluorescence studies confirmed that SRSF1-3 and TOP1 are co-localized in the nucleus. Furthermore, Proximity Ligation Assay corroborated the direct interaction between SRSF1-3 and TOP1. An interaction between SRSF1-3 and TOP1 suggests that SRSF1-3 likely influences the TOP1 activity and consequently can aid in SHM. Accordingly, SRSF1-3 probably acts as a link between TOP1 and SHM, by spatially regulating TOP1 activity at the Ig locus. We also confirmed the interaction between SRSF1-3 and AID in chicken B-cells. Thus, SRSF1-3 shows dual-regulation of SHM, via interacting with AID as well as TOP1.
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10
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Kawaguchi Y, Nariki H, Kawamoto N, Kanehiro Y, Miyazaki S, Suzuki M, Magari M, Tokumitsu H, Kanayama N. SRSF1-3 contributes to diversification of the immunoglobulin variable region gene by promoting accumulation of AID in the nucleus. Biochem Biophys Res Commun 2017; 485:261-266. [DOI: 10.1016/j.bbrc.2017.02.097] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 02/19/2017] [Indexed: 01/06/2023]
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11
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Yan Q, Xia X, Sun Z, Fang Y. Depletion of Arabidopsis SC35 and SC35-like serine/arginine-rich proteins affects the transcription and splicing of a subset of genes. PLoS Genet 2017; 13:e1006663. [PMID: 28273088 PMCID: PMC5362245 DOI: 10.1371/journal.pgen.1006663] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 03/22/2017] [Accepted: 02/28/2017] [Indexed: 12/23/2022] Open
Abstract
Serine/arginine-rich (SR) proteins are important splicing factors which play significant roles in spliceosome assembly and splicing regulation. However, little is known regarding their biological functions in plants. Here, we analyzed the phenotypes of mutants upon depleting different subfamilies of Arabidopsis SR proteins. We found that loss of the functions of SC35 and SC35-like (SCL) proteins cause pleiotropic changes in plant morphology and development, including serrated leaves, late flowering, shorter roots and abnormal silique phyllotaxy. Using RNA-seq, we found that SC35 and SCL proteins play roles in the pre-mRNA splicing. Motif analysis revealed that SC35 and SCL proteins preferentially bind to a specific RNA sequence containing the AGAAGA motif. In addition, the transcriptions of a subset of genes are affected by the deletion of SC35 and SCL proteins which interact with NRPB4, a specific subunit of RNA polymerase II. The splicing of FLOWERING LOCUS C (FLC) intron1 and transcription of FLC were significantly regulated by SC35 and SCL proteins to control Arabidopsis flowering. Therefore, our findings provide mechanistic insight into the functions of plant SC35 and SCL proteins in the regulation of splicing and transcription in a direct or indirect manner to maintain the proper expression of genes and development. SR proteins were identified to be important splicing factors. This work generated mutants of different subfamilies of the classic Arabidopsis SR proteins. Genetic analysis revealed that loss of the function of SC35/SCL proteins influences the plant development. This study revealed SC35/SCL proteins regulate alternative splicing, preferentially bind a specific RNA motif, interact with NRPB4, and affect the transcription of a subset of genes. This study further revealed that SC35/SCL proteins control flowering by regulating the splicing and transcription of FLC. These results shed light on the functions of SR proteins in plants.
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Affiliation(s)
- Qingqing Yan
- National key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Xi Xia
- National key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Zhenfei Sun
- National key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Yuda Fang
- National key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
- * E-mail:
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12
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Krepl M, Cléry A, Blatter M, Allain FHT, Sponer J. Synergy between NMR measurements and MD simulations of protein/RNA complexes: application to the RRMs, the most common RNA recognition motifs. Nucleic Acids Res 2016; 44:6452-70. [PMID: 27193998 PMCID: PMC5291263 DOI: 10.1093/nar/gkw438] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/30/2016] [Accepted: 05/05/2016] [Indexed: 01/28/2023] Open
Abstract
RNA recognition motif (RRM) proteins represent an abundant class of proteins playing key roles in RNA biology. We present a joint atomistic molecular dynamics (MD) and experimental study of two RRM-containing proteins bound with their single-stranded target RNAs, namely the Fox-1 and SRSF1 complexes. The simulations are used in conjunction with NMR spectroscopy to interpret and expand the available structural data. We accumulate more than 50 μs of simulations and show that the MD method is robust enough to reliably describe the structural dynamics of the RRM-RNA complexes. The simulations predict unanticipated specific participation of Arg142 at the protein-RNA interface of the SRFS1 complex, which is subsequently confirmed by NMR and ITC measurements. Several segments of the protein-RNA interface may involve competition between dynamical local substates rather than firmly formed interactions, which is indirectly consistent with the primary NMR data. We demonstrate that the simulations can be used to interpret the NMR atomistic models and can provide qualified predictions. Finally, we propose a protocol for 'MD-adapted structure ensemble' as a way to integrate the simulation predictions and expand upon the deposited NMR structures. Unbiased μs-scale atomistic MD could become a technique routinely complementing the NMR measurements of protein-RNA complexes.
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Affiliation(s)
- Miroslav Krepl
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Antoine Cléry
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Markus Blatter
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland Global Discovery Chemistry, Novartis Institute for BioMedical Research, Basel CH-4002, Switzerland
| | - Frederic H T Allain
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Jiri Sponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65 Brno, Czech Republic CEITEC - Central European Institute of Technology, Masaryk University, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
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13
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Ladd AN. New Insights Into the Role of RNA-Binding Proteins in the Regulation of Heart Development. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 324:125-85. [PMID: 27017008 DOI: 10.1016/bs.ircmb.2015.12.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The regulation of gene expression during development takes place both at the transcriptional and posttranscriptional levels. RNA-binding proteins (RBPs) regulate pre-mRNA processing, mRNA localization, stability, and translation. Many RBPs are expressed in the heart and have been implicated in heart development, function, or disease. This chapter will review the current knowledge about RBPs in the developing heart, focusing on those that regulate posttranscriptional gene expression. The involvement of RBPs at each stage of heart development will be considered in turn, including the establishment of specific cardiac cell types and formation of the primitive heart tube, cardiac morphogenesis, and postnatal maturation and aging. The contributions of RBPs to cardiac birth defects and heart disease will also be considered in these contexts. Finally, the interplay between RBPs and other regulatory factors in the developing heart, such as transcription factors and miRNAs, will be discussed.
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Affiliation(s)
- A N Ladd
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States of America.
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14
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Tethered Function Assays as Tools to Elucidate the Molecular Roles of RNA-Binding Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 907:61-88. [PMID: 27256382 DOI: 10.1007/978-3-319-29073-7_3] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Dynamic regulation of RNA molecules is critical to the survival and development of cells. Messenger RNAs are transcribed in the nucleus as intron-containing pre-mRNAs and bound by RNA-binding proteins, which control their fate by regulating RNA stability, splicing, polyadenylation, translation, and cellular localization. Most RBPs have distinct mRNA-binding and functional domains; thus, the function of an RBP can be studied independently of RNA-binding by artificially recruiting the RBP to a reporter RNA and then measuring the effect of RBP recruitment on reporter splicing, stability, translational efficiency, or intracellular trafficking. These tethered function assays therefore do not require prior knowledge of the RBP's endogenous RNA targets or its binding sites within these RNAs. Here, we provide an overview of the experimental strategy and the strengths and limitations of common tethering systems. We illustrate specific examples of the application of the assay in elucidating the function of various classes of RBPs. We also discuss how classic tethering assay approaches and insights gained from them have been empowered by more recent technological advances, including efficient genome editing and high-throughput RNA-sequencing.
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15
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Pilaz LJ, Silver DL. Post-transcriptional regulation in corticogenesis: how RNA-binding proteins help build the brain. WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 6:501-15. [PMID: 26088328 DOI: 10.1002/wrna.1289] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 05/01/2015] [Accepted: 05/01/2015] [Indexed: 12/17/2022]
Abstract
The cerebral cortex, the brain structure responsible for our higher cognitive functions, is built during embryonic development in a process called corticogenesis. During corticogenesis, neural stem cells generate distinct populations of progenitors and excitatory neurons. These new neurons migrate radially in the cortex, eventually forming neuronal layers and establishing synaptic connections with other neurons both within and outside the cortex. Perturbations to corticogenesis can result in severe neurodevelopmental disorders, thus emphasizing the need to better understand molecular regulation of brain development. Recent studies in both model organisms and humans have collectively highlighted roles for post-transcriptional regulation in virtually all steps of corticogenesis. Genomic approaches have revealed global RNA changes associated with spatial and temporal regulation of cortical development. Additionally, genetic studies have uncovered RNA-binding proteins (RBPs) critical for cell proliferation, differentiation, and migration within the developing neocortex. Many of these same RBPs play causal roles in neurodevelopmental pathologies. In the developing neocortex, RBPs influence diverse steps of mRNA metabolism, including splicing, stability, translation, and localization. With the advent of new technologies, researchers have begun to uncover key transcripts regulated by these RBPs. Given the complexity of the developing mammalian cortex, a major challenge for the future will be to understand how dynamic RNA regulation occurs within heterogeneous cell populations, across space and time. In sum, post-transcriptional regulation has emerged as a critical mechanism for driving corticogenesis and exciting direction of future research.
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Affiliation(s)
- Louis-Jan Pilaz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
| | - Debra L Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA.,Department of Cell Biology, Duke University Medical Center, Durham, NC, USA.,Department of Neurobiology, Duke University Medical Center, Durham, NC, USA.,Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC, USA
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16
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Chan SL, Huppertz I, Yao C, Weng L, Moresco JJ, Yates JR, Ule J, Manley JL, Shi Y. CPSF30 and Wdr33 directly bind to AAUAAA in mammalian mRNA 3' processing. Genes Dev 2014; 28:2370-80. [PMID: 25301780 PMCID: PMC4215182 DOI: 10.1101/gad.250993.114] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
AAUAAA is the most highly conserved motif in eukaryotic mRNA polyadenylation sites and, in mammals, is specifically recognized by the multisubunit CPSF complex. Chan et al. found that CPSF subunits CPSF30 and Wdr33 directly contact AAUAAA. The CPSF30–RNA interaction is essential for mRNA 3′ processing and is primarily mediated by its zinc fingers 2 and 3, which are specifically targeted by the influenza protein NS1A to suppress host mRNA 3′ processing. AAUAAA is the most highly conserved motif in eukaryotic mRNA polyadenylation sites and, in mammals, is specifically recognized by the multisubunit CPSF (cleavage and polyadenylation specificity factor) complex. Despite its critical functions in mRNA 3′ end formation, the molecular basis for CPSF–AAUAAA interaction remains poorly defined. The CPSF subunit CPSF160 has been implicated in AAUAAA recognition, but direct evidence has been lacking. Using in vitro and in vivo assays, we unexpectedly found that CPSF subunits CPSF30 and Wdr33 directly contact AAUAAA. Importantly, the CPSF30–RNA interaction is essential for mRNA 3′ processing and is primarily mediated by its zinc fingers 2 and 3, which are specifically targeted by the influenza protein NS1A to suppress host mRNA 3′ processing. Our data suggest that AAUAAA recognition in mammalian mRNA 3′ processing is more complex than previously thought and involves multiple protein–RNA interactions.
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Affiliation(s)
- Serena L Chan
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California at Irvine, Irvine, California 92697, USA
| | - Ina Huppertz
- Department of Molecular Neuroscience, University College London Institute of Neurology, London WC1N 3BG, United Kingdom; Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Chengguo Yao
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California at Irvine, Irvine, California 92697, USA
| | - Lingjie Weng
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California at Irvine, Irvine, California 92697, USA; Institute for Genomics and Bioinformatics, Department of Computer Science, University of California at Irvine Irvine, California 92697, USA
| | - James J Moresco
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Jernej Ule
- Department of Molecular Neuroscience, University College London Institute of Neurology, London WC1N 3BG, United Kingdom; Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Yongsheng Shi
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California at Irvine, Irvine, California 92697, USA
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17
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Regulation of gene expression programmes by serine–arginine rich splicing factors. Semin Cell Dev Biol 2014; 32:11-21. [DOI: 10.1016/j.semcdb.2014.03.011] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 03/11/2014] [Indexed: 12/21/2022]
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18
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Roberts JM, Ennajdaoui H, Edmondson C, Wirth B, Sanford J, Chen B. Splicing factor TRA2B is required for neural progenitor survival. J Comp Neurol 2014; 522:372-92. [PMID: 23818142 PMCID: PMC3855887 DOI: 10.1002/cne.23405] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/20/2013] [Accepted: 06/21/2013] [Indexed: 01/08/2023]
Abstract
Alternative splicing of pre-mRNAs can rapidly regulate the expression of large groups of proteins. The RNA binding protein TRA2B (SFRS10) plays well-established roles in developmentally regulated alternative splicing during Drosophila sexual differentiation. TRA2B is also essential for mammalian embryogenesis and is implicated in numerous human diseases. Precise regulation of alternative splicing is critical to the development and function of the central nervous system; however, the requirements for specific splicing factors in neurogenesis are poorly understood. This study focuses on the role of TRA2B in mammalian brain development. We show that, during murine cortical neurogenesis, TRA2B is expressed in both neural progenitors and cortical projection neurons. Using cortex-specific Tra2b mutant mice, we show that TRA2B depletion results in apoptosis of the neural progenitor cells as well as disorganization of the cortical plate. Thus, TRA2B is essential for proper development of the cerebral cortex.
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Affiliation(s)
- Jacqueline M Roberts
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Hanane Ennajdaoui
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Carina Edmondson
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Brunhilde Wirth
- Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne 50931, Germany
| | - Jeremy Sanford
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Bin Chen
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
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19
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Xiang S, Gapsys V, Kim HY, Bessonov S, Hsiao HH, Möhlmann S, Klaukien V, Ficner R, Becker S, Urlaub H, Lührmann R, de Groot B, Zweckstetter M. Phosphorylation drives a dynamic switch in serine/arginine-rich proteins. Structure 2013; 21:2162-74. [PMID: 24183573 DOI: 10.1016/j.str.2013.09.014] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/25/2013] [Accepted: 09/27/2013] [Indexed: 11/25/2022]
Abstract
Serine/arginine-rich (SR) proteins are important players in RNA metabolism and are extensively phosphorylated at serine residues in RS repeats. Here, we show that phosphorylation switches the RS domain of the serine/arginine-rich splicing factor 1 from a fully disordered state to a partially rigidified arch-like structure. Nuclear magnetic resonance spectroscopy in combination with molecular dynamics simulations revealed that the conformational switch is restricted to RS repeats, critically depends on the phosphate charge state and strongly decreases the conformational entropy of RS domains. The dynamic switch also occurs in the 100 kDa SR-related protein hPrp28, for which phosphorylation at the RS repeat is required for spliceosome assembly. Thus, a phosphorylation-induced dynamic switch is common to the class of serine/arginine-rich proteins and provides a molecular basis for the functional redundancy of serine/arginine-rich proteins and the profound influence of RS domain phosphorylation on protein-protein and protein-RNA interactions.
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Affiliation(s)
- Shengqi Xiang
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany
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20
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Blech-Hermoni Y, Ladd AN. RNA binding proteins in the regulation of heart development. Int J Biochem Cell Biol 2013; 45:2467-78. [PMID: 23973289 DOI: 10.1016/j.biocel.2013.08.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 08/09/2013] [Accepted: 08/13/2013] [Indexed: 11/28/2022]
Abstract
In vivo, RNA molecules are constantly accompanied by RNA binding proteins (RBPs), which are intimately involved in every step of RNA biology, including transcription, editing, splicing, transport and localization, stability, and translation. RBPs therefore have opportunities to shape gene expression at multiple levels. This capacity is particularly important during development, when dynamic chemical and physical changes give rise to complex organs and tissues. This review discusses RBPs in the context of heart development. Since the targets and functions of most RBPs--in the heart and at large--are not fully understood, this review focuses on the expression and roles of RBPs that have been implicated in specific stages of heart development or developmental pathology. RBPs are involved in nearly every stage of cardiogenesis, including the formation, morphogenesis, and maturation of the heart. A fuller understanding of the roles and substrates of these proteins could ultimately provide attractive targets for the design of therapies for congenital heart defects, cardiovascular disease, or cardiac tissue repair.
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Affiliation(s)
- Yotam Blech-Hermoni
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA; Program in Cell Biology, Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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21
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Cléry A, Sinha R, Anczuków O, Corrionero A, Moursy A, Daubner GM, Valcárcel J, Krainer AR, Allain FHT. Isolated pseudo-RNA-recognition motifs of SR proteins can regulate splicing using a noncanonical mode of RNA recognition. Proc Natl Acad Sci U S A 2013; 110:E2802-11. [PMID: 23836656 PMCID: PMC3725064 DOI: 10.1073/pnas.1303445110] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Serine/arginine (SR) proteins, one of the major families of alternative-splicing regulators in Eukarya, have two types of RNA-recognition motifs (RRMs): a canonical RRM and a pseudo-RRM. Although pseudo-RRMs are crucial for activity of SR proteins, their mode of action was unknown. By solving the structure of the human SRSF1 pseudo-RRM bound to RNA, we discovered a very unusual and sequence-specific RNA-binding mode that is centered on one α-helix and does not involve the β-sheet surface, which typically mediates RNA binding by RRMs. Remarkably, this mode of binding is conserved in all pseudo-RRMs tested. Furthermore, the isolated pseudo-RRM is sufficient to regulate splicing of about half of the SRSF1 target genes tested, and the bound α-helix is a pivotal element for this function. Our results strongly suggest that SR proteins with a pseudo-RRM frequently regulate splicing by competing with, rather than recruiting, spliceosome components, using solely this unusual RRM.
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Affiliation(s)
- Antoine Cléry
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Rahul Sinha
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Olga Anczuków
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Anna Corrionero
- Institució Catalana de Recerca i Estudis Avançats, Universitat Pompeu Fabra 08003 Barcelona, Spain; and
- Centre de Regulació Genòmica, 08003 Barcelona, Spain
| | - Ahmed Moursy
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Gerrit M. Daubner
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Juan Valcárcel
- Institució Catalana de Recerca i Estudis Avançats, Universitat Pompeu Fabra 08003 Barcelona, Spain; and
- Centre de Regulació Genòmica, 08003 Barcelona, Spain
| | | | - Frédéric H.-T. Allain
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
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22
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Thomas J, Palusa SG, Prasad KVSK, Ali GS, Surabhi GK, Ben-Hur A, Abdel-Ghany SE, Reddy ASN. Identification of an intronic splicing regulatory element involved in auto-regulation of alternative splicing of SCL33 pre-mRNA. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 72:935-46. [PMID: 22913769 DOI: 10.1111/tpj.12004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In Arabidopsis, pre-mRNAs of serine/arginine-rich (SR) proteins undergo extensive alternative splicing (AS). However, little is known about the cis-elements and trans-acting proteins involved in regulating AS. Using a splicing reporter (GFP-intron-GFP), consisting of the GFP coding sequence interrupted by an alternatively spliced intron of SCL33, we investigated whether cis-elements within this intron are sufficient for AS, and which SR proteins are necessary for regulated AS. Expression of the splicing reporter in protoplasts faithfully produced all splice variants from the intron, suggesting that cis-elements required for AS reside within the intron. To determine which SR proteins are responsible for AS, the splicing pattern of the GFP-intron-GFP reporter was investigated in protoplasts of three single and three double mutants of SR genes. These analyses revealed that SCL33 and a closely related paralog, SCL30a, are functionally redundant in generating specific splice variants from this intron. Furthermore, SCL33 protein bound to a conserved sequence in this intron, indicating auto-regulation of AS. Mutations in four GAAG repeats within the conserved region impaired generation of the same splice variants that are affected in the scl33 scl30a double mutant. In conclusion, we have identified the first intronic cis-element involved in AS of a plant SR gene, and elucidated a mechanism for auto-regulation of AS of this intron.
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Affiliation(s)
- Julie Thomas
- Department of Biology, Program in Molecular Plant Biology, Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USADepartment of Computer Science and Program in Molecular Plant Biology, Colorado State University, Fort Collins, CO 80523, USA
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23
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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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24
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Hsin JP, Sheth A, Manley JL. RNAP II CTD phosphorylated on threonine-4 is required for histone mRNA 3' end processing. Science 2012; 334:683-6. [PMID: 22053051 DOI: 10.1126/science.1206034] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The RNA polymerase II (RNAP II) largest subunit contains a C-terminal domain (CTD) with up to 52 Tyr(1)-Ser(2)-Pro(3)-Thr(4)-Ser(5)-Pro(6)-Ser(7) consensus repeats. Serines 2, 5, and 7 are known to be phosphorylated, and these modifications help to orchestrate the interplay between transcription and processing of messenger RNA (mRNA) precursors. Here, we provide evidence that phosphorylation of CTD Thr(4) residues is required specifically for histone mRNA 3' end processing, functioning to facilitate recruitment of 3' processing factors to histone genes. Like Ser(2), Thr(4) phosphorylation requires the CTD kinase CDK9 and is evolutionarily conserved from yeast to human. Our data thus illustrate how a CTD modification can play a highly specific role in facilitating efficient gene expression.
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Affiliation(s)
- Jing-Ping Hsin
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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25
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Activation-induced cytidine deaminase (AID)-dependent somatic hypermutation requires a splice isoform of the serine/arginine-rich (SR) protein SRSF1. Proc Natl Acad Sci U S A 2012; 109:1216-21. [PMID: 22232677 DOI: 10.1073/pnas.1120368109] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Somatic hypermutation (SHM) of Ig variable region (IgV) genes requires both IgV transcription and the enzyme activation-induced cytidine deaminase (AID). Identification of a cofactor responsible for the fact that IgV genes are much more sensitive to AID-induced mutagenesis than other genes is a key question in immunology. Here, we describe an essential role for a splice isoform of the prototypical serine/arginine-rich (SR) protein SRSF1, termed SRSF1-3, in AID-induced SHM in a DT40 chicken B-cell line. Unexpectedly, we found that SHM does not occur in a DT40 line lacking SRSF1-3 (DT40-ASF), although it is readily detectable in parental DT40 cells. Strikingly, overexpression of AID in DT40-ASF cells led to a large increase in nonspecific (off-target) mutations. In contrast, introduction of SRSF1-3, but not SRSF1, into these cells specifically restored SHM without increasing off-target mutations. Furthermore, we found that SRSF1-3 binds preferentially to the IgV gene and inhibits processing of the Ig transcript, providing a mechanism by which SRSF1-3 makes the IgV gene available for AID-dependent SHM. SRSF1 not only acts as an essential splicing factor but also regulates diverse aspects of mRNA metabolism and maintains genome stability. Our findings, thus, define an unexpected and important role for SRSF1, particularly for its splice variant, in enabling AID to function specifically on its natural substrate during SHM.
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26
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Gan W, Guan Z, Liu J, Gui T, Shen K, Manley JL, Li X. R-loop-mediated genomic instability is caused by impairment of replication fork progression. Genes Dev 2011; 25:2041-56. [PMID: 21979917 DOI: 10.1101/gad.17010011] [Citation(s) in RCA: 324] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Transcriptional R loops are anomalous RNA:DNA hybrids that have been detected in organisms from bacteria to humans. These structures have been shown in eukaryotes to result in DNA damage and rearrangements; however, the mechanisms underlying these effects have remained largely unknown. To investigate this, we first show that R-loop formation induces chromosomal DNA rearrangements and recombination in Escherichia coli, just as it does in eukaryotes. More importantly, we then show that R-loop formation causes DNA replication fork stalling, and that this in fact underlies the effects of R loops on genomic stability. Strikingly, we found that attenuation of replication strongly suppresses R-loop-mediated DNA rearrangements in both E. coli and HeLa cells. Our findings thus provide a direct demonstration that R-loop formation impairs DNA replication and that this is responsible for the deleterious effects of R loops on genome stability from bacteria to humans.
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Affiliation(s)
- Wenjian Gan
- College of Life Sciences, Peking University, Beijing 100871, China
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27
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Abstract
Genome-wide analyses of metazoan transcriptomes have revealed an unexpected level of mRNA diversity that is generated by alternative splicing. Recently, regulatory networks have been identified through which splicing promotes dynamic remodelling of the transcriptome to promote physiological changes, which involve robust and coordinated alternative splicing transitions. The regulation of splicing in yeast, worms, flies and vertebrates affects a variety of biological processes. The functional classes of genes that are regulated by alternative splicing include both those with widespread homeostatic activities and those with cell-type-specific functions. Alternative splicing can drive determinative physiological change or can have a permissive role by providing mRNA variability that is used by other regulatory mechanisms.
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28
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Verduci L, Simili M, Rizzo M, Mercatanti A, Evangelista M, Mariani L, Rainaldi G, Pitto L. MicroRNA (miRNA)-mediated interaction between leukemia/lymphoma-related factor (LRF) and alternative splicing factor/splicing factor 2 (ASF/SF2) affects mouse embryonic fibroblast senescence and apoptosis. J Biol Chem 2010; 285:39551-63. [PMID: 20923760 DOI: 10.1074/jbc.m110.114736] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Leukemia/lymphoma-related factor (LRF) is a transcriptional repressor, which by recruiting histone deacetylases specifically represses p19/ARF expression, thus behaving as an oncogene. Conversely, in mouse embryonic fibroblasts (MEF), LRF inhibition causes aberrant p19ARF up-regulation resulting in proliferative defects and premature senescence. We have recently shown that LRF is controlled by microRNAs. Here we show that LRF acts on MEF proliferation and senescence/apoptosis by repressing miR-28 and miR-505, revealing a regulatory circuit where microRNAs (miRNAs) work both upstream and downstream of LRF. By analyzing miRNA expression profiles of MEF transfected with LRF-specific short interfering RNAs, we found that miR-28 and miR-505 are modulated by LRF. Both miRNAs are predicted to target alternative splicing factor/splicing factor 2 (ASF/SF2), a serine/arginine protein essential for cell viability. In vertebrates, loss or inactivation of ASF/SF2 may result in genomic instability and induce G(2) cell cycle arrest and apoptosis. We showed that miR-28 and miR-505 modulate ASF/SF2 by directly binding ASF/SF2 3'-UTR. Decrease in LRF causes a decrease in ASF/SF2, which depends on up-regulation of miR-28 and miR-505. Alteration of each of the members of the LRF/miR-28/miR-505/ASF/SF2 axis affects MEF proliferation and the number of senescent and apoptotic cells. Consistently, the axis is coordinately modulated as cell senescence increases with passages in MEF culture. In conclusion, we show that LRF-dependent miRNAs miR-28 and miR-505 control MEF proliferation and survival by targeting ASF/SF2 and suggest a central role of LRF-related miRNAs, in addition to the role of LRF-dependent p53 control, in cellular homeostasis.
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Affiliation(s)
- Lorena Verduci
- Laboratory of Gene and Molecular Therapy, Institute of Clinical Physiology, Consiglio Nazionale delle Ricerche, 56124 Pisa, Italy
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29
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Li D, Morales A, Gonzalez-Quintana J, Norton N, Siegfried JD, Hofmeyer M, Hershberger RE. Identification of novel mutations in RBM20 in patients with dilated cardiomyopathy. Clin Transl Sci 2010; 3:90-7. [PMID: 20590677 DOI: 10.1111/j.1752-8062.2010.00198.x] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The genetic basis of most of dilated cardiomyopathy (DCM) cases remains unknown. A recent study indicated that mutations in a highly localized five amino acid hotspot in exon 9 of RBM20, a gene encoding a ribonucleic acid-binding protein, caused aggressive DCM. We undertook this study to confi rm and extend the nature of RBM20 mutations in another DCM cohort. Clinical cardiovascular data, family histories, and blood samples were collected from patients with idiopathic DCM. DNA from 312 DCM probands was sequenced for nucleotide alterations in exons 6 through 9 of RBM20, and additional family members as possible. We found six unique RBM20 rare variants in six unrelated probands (1.9%). Four mutations, two of which were novel (R634W and R636C) and two previously identified (R634Q and R636H), were identified in a five amino acid hotspot in exon 6. Two other novel variants (V535I in exon 6 and R716Q in exon 9) were outside of this hotspot. Age of onset and severity of heart failure were variable, as were arrhythmias and conduction system defects, but many subjects suffered severe heart failure resulting in early death or cardiac transplantation. This article concludes that DCM in patients with RBM20 mutations is associated with advanced disease.
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Affiliation(s)
- Duanxiang Li
- Cardiovascular Division, University of Miami Miller School of Medicine, Miami, Florida, USA
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30
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Abstract
Although members of the serine (S)- and arginine (R)-rich splicing factor family (SR proteins) were initially purified on the basis of their splicing activity in the nucleus, there is recent documentation that they exhibit carbohydrate-binding activity at the cell surface. In contrast, galectins were isolated on the basis of their saccharide-binding activity and cell surface localization. Surprisingly, however, two members (galectin-1 and galectin-3) can be found in association with nuclear ribonucleoprotein complexes including the spliceosome and, using a cell-free assay, have been shown to be required splicing factors. Thus, despite the difference in terms of their original points of interest, it now appears that members of the two protein families share four key properties: (a) nuclear and cytoplasmic distribution; (b) pre-mRNA splicing activity; (c) carbohydrate-binding activity; and (d) cell surface localization in specific cells. These findings provoke stimulating questions regarding the relationship between splicing factors in the nucleus and carbohydrate-binding proteins at the cell surface.
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Affiliation(s)
- Kevin C Haudek
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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31
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Olshavsky NA, Comstock CES, Schiewer MJ, Augello MA, Hyslop T, Sette C, Zhang J, Parysek LM, Knudsen KE. Identification of ASF/SF2 as a critical, allele-specific effector of the cyclin D1b oncogene. Cancer Res 2010; 70:3975-84. [PMID: 20460515 DOI: 10.1158/0008-5472.can-09-3468] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The cyclin D1b oncogene arises from alternative splicing of the CCND1 transcript, and harbors markedly enhanced oncogenic functions not shared by full-length cyclin D1 (cyclin D1a). Recent studies showed that cyclin D1b is selectively induced in a subset of tissues as a function of tumorigenesis; however, the underlying mechanism(s) that control tumor-specific cyclin D1b induction remain unsolved. Here, we identify the RNA-binding protein ASF/SF2 as a critical, allele-specific, disease-relevant effector of cyclin D1b production. Initially, it was observed that SF2 associates with cyclin D1b mRNA (transcript-b) in minigene analyses and with endogenous transcript in prostate cancer (PCa) cells. SF2 association was altered by the CCND1 G/A870 polymorphism, which resides in the splice donor site controlling transcript-b production. This finding was significant, as the A870 allele promotes cyclin D1b in benign prostate tissue, but in primary PCa, cyclin D1b production is independent of A870 status. Data herein provide a basis for this disparity, as tumor-associated induction of SF2 predominantly results in binding to and accumulation of G870-derived transcript-b. Finally, the relevance of SF2 function was established, as SF2 strongly correlated with cyclin D1b (but not cyclin D1a) in human PCa. Together, these studies identify a novel mechanism by which cyclin D1b is induced in cancer, and reveal significant evidence of a factor that cooperates with a risk-associated polymorphism to alter cyclin D1 isoform production. Identification of SF2 as a disease-relevant effector of cyclin D1b provides a basis for future studies designed to suppress the oncogenic alternative splicing event.
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Affiliation(s)
- Nicholas A Olshavsky
- Department of Cancer and Cell Biology, University of Cincinnati, Cincinnati, Ohio, USA
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32
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O'Leary DA, Sharif O, Anderson P, Tu B, Welch G, Zhou Y, Caldwell JS, Engels IH, Brinker A. Identification of small molecule and genetic modulators of AON-induced dystrophin exon skipping by high-throughput screening. PLoS One 2009; 4:e8348. [PMID: 20020055 PMCID: PMC2791862 DOI: 10.1371/journal.pone.0008348] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 11/23/2009] [Indexed: 11/28/2022] Open
Abstract
One therapeutic approach to Duchenne Muscular Dystrophy (DMD) recently entering clinical trials aims to convert DMD phenotypes to that of a milder disease variant, Becker Muscular Dystrophy (BMD), by employing antisense oligonucleotides (AONs) targeting splice sites, to induce exon skipping and restore partial dystrophin function. In order to search for small molecule and genetic modulators of AON-dependent and independent exon skipping, we screened ∼10,000 known small molecule drugs, >17,000 cDNA clones, and >2,000 kinase- targeted siRNAs against a 5.6 kb luciferase minigene construct, encompassing exon 71 to exon 73 of human dystrophin. As a result, we identified several enhancers of exon skipping, acting on both the reporter construct as well as endogenous dystrophin in mdx cells. Multiple mechanisms of action were identified, including histone deacetylase inhibition, tubulin modulation and pre-mRNA processing. Among others, the nucleolar protein NOL8 and staufen RNA binding protein homolog 2 (Stau2) were found to induce endogenous exon skipping in mdx cells in an AON-dependent fashion. An unexpected but recurrent theme observed in our screening efforts was the apparent link between the inhibition of cell cycle progression and the induction of exon skipping.
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Affiliation(s)
- Debra A. O'Leary
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
- * E-mail: (DAO); (IHE)
| | - Orzala Sharif
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Paul Anderson
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Buu Tu
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Genevieve Welch
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Yingyao Zhou
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Jeremy S. Caldwell
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Ingo H. Engels
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
- * E-mail: (DAO); (IHE)
| | - Achim Brinker
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
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33
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Conditional transformation of immunoglobulin mutation pattern from gene conversion into point mutation by controlling XRCC3 expression in the DT40 B cell line. J Biosci Bioeng 2009; 109:407-10. [PMID: 20226386 DOI: 10.1016/j.jbiosc.2009.09.050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Accepted: 09/29/2009] [Indexed: 12/12/2022]
Abstract
A hypermutating B cell line DT40 is useful for screening antibodies and improving affinity of the selected antibodies in vitro. To perform affinity maturation efficiently, we generated an engineered DT40 line whose immunoglobulin mutation pattern can be transformed from gene conversion into point mutation by conditional suppression of XRCC3 expression.
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34
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Feng Y, Valley MT, Lazar J, Yang AL, Bronson RT, Firestein S, Coetzee WA, Manley JL. SRp38 regulates alternative splicing and is required for Ca(2+) handling in the embryonic heart. Dev Cell 2009; 16:528-38. [PMID: 19386262 DOI: 10.1016/j.devcel.2009.02.009] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Revised: 01/09/2009] [Accepted: 02/12/2009] [Indexed: 11/18/2022]
Abstract
SRp38 is an atypical SR protein splicing regulator. To define the functions of SRp38 in vivo, we generated SRp38 null mice. The majority of homozygous mutants survived only until E15.5 and displayed multiple cardiac defects. Evaluation of gene expression profiles in the SRp38(-/-) embryonic heart revealed a defect in processing of the pre-mRNA encoding cardiac triadin, a protein that functions in regulation of Ca(2+) release from the sarcoplasmic reticulum during excitation-contraction coupling. This defect resulted in significantly reduced levels of triadin, as well as those of the interacting protein calsequestrin 2. Purified SRp38 was shown to bind specifically to the regulated exon and to modulate triadin splicing in vitro. Extending these results, isolated SRp38(-/-) embryonic cardiomyocytes displayed defects in Ca(2+) handling compared with wild-type controls. Taken together, our results demonstrate that SRp38 regulates cardiac-specific alternative splicing of triadin pre-mRNA and, reflecting this, is essential for proper Ca(2+) handling during embryonic heart development.
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Affiliation(s)
- Ying Feng
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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35
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Loomis RJ, Naoe Y, Parker JB, Savic V, Bozovsky MR, Macfarlan T, Manley JL, Chakravarti D. Chromatin binding of SRp20 and ASF/SF2 and dissociation from mitotic chromosomes is modulated by histone H3 serine 10 phosphorylation. Mol Cell 2009; 33:450-61. [PMID: 19250906 DOI: 10.1016/j.molcel.2009.02.003] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 06/03/2008] [Accepted: 02/04/2009] [Indexed: 11/16/2022]
Abstract
Histone H3 serine 10 phosphorylation is a hallmark of mitotic chromosomes, but its full function remains to be elucidated. We report here that two SR protein splicing factors, SRp20 and ASF/SF2, associate with interphase chromatin, are released from hyperphosphorylated mitotic chromosomes, but reassociate with chromatin late in M-phase. Inhibition of Aurora B kinase diminished histone H3 serine 10 phosphorylation and increased SRp20 and ASF/SF2 retention on mitotic chromosomes. Unexpectedly, we also found that HP1 proteins interact with ASF/SF2 in mitotic cells. Strikingly, siRNA-mediated knockdown of ASF/SF2 caused retention of HP1 proteins on mitotic chromatin. Finally, ASF/SF2-depleted cells released from a mitotic block displayed delayed G0/G1 entry, suggesting a functional consequence of these interactions. These findings underscore the evolving role of histone H3 phosphorylation and demonstrate a direct, functional, and histone-modification-regulated association of SRp20 and ASF/SF2 with chromatin.
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Affiliation(s)
- Rebecca J Loomis
- Division of Reproductive Biology Research, Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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36
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Zhong XY, Ding JH, Adams JA, Ghosh G, Fu XD. Regulation of SR protein phosphorylation and alternative splicing by modulating kinetic interactions of SRPK1 with molecular chaperones. Genes Dev 2009; 23:482-95. [PMID: 19240134 DOI: 10.1101/gad.1752109] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Phosphorylation is essential for the SR family of splicing factors/regulators to function in constitutive and regulated pre-mRNA splicing; yet both hypo- and hyperphosphorylation of SR proteins are known to inhibit splicing, indicating that SR protein phosphorylation must be tightly regulated in the cell. However, little is known how SR protein phosphorylation might be regulated during development or in response to specific signaling events. Here, we report that SRPK1, a ubiquitously expressed SR protein-specific kinase, directly binds to the cochaperones Hsp40/DNAjc8 and Aha1, which mediate dynamic interactions of the kinase with the major molecular chaperones Hsp70 and Hsp90 in mammalian cells. Inhibition of the Hsp90 ATPase activity induces dissociation of SRPK1 from the chaperone complexes, which can also be triggered by a stress signal (osmotic shock), resulting in translocation of the kinase from the cytoplasm to the nucleus, differential phosphorylation of SR proteins, and alteration of splice site selection. These findings connect the SRPK to the molecular chaperone system that has been implicated in numerous signal transduction pathways and provide mechanistic insights into complex regulation of SR protein phosphorylation and alternative splicing in response to developmental cues and cellular signaling.
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Affiliation(s)
- Xiang-Yang Zhong
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093, USA
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37
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Björk P, Jin S, Zhao J, Singh OP, Persson JO, Hellman U, Wieslander L. Specific combinations of SR proteins associate with single pre-messenger RNAs in vivo and contribute different functions. J Cell Biol 2009; 184:555-68. [PMID: 19221196 PMCID: PMC2654125 DOI: 10.1083/jcb.200806156] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Accepted: 01/14/2009] [Indexed: 02/03/2023] Open
Abstract
Serine/arginine-rich (SR) proteins are required for messenger RNA (mRNA) processing, export, surveillance, and translation. We show that in Chironomus tentans, nascent transcripts associate with multiple types of SR proteins in specific combinations. Alternative splicing factor (ASF)/SF2, SC35, 9G8, and hrp45/SRp55 are all present in Balbiani ring (BR) pre-messenger ribonucleoproteins (mRNPs) preferentially when introns appear in the pre-mRNA and when cotranscriptional splicing takes place. However, hrp45/SRp55 is distributed differently in the pre-mRNPs along the gene compared with ASF/SF2, SC35, and 9G8, suggesting functional differences. All four SR proteins are associated with the BR mRNPs during export to the cytoplasm. Interference with SC35 indicates that SC35 is important for the coordination of splicing, transcription, and 3' end processing and also for nucleocytoplasmic export. ASF/SF2 is associated with polyribosomes, whereas SC35, 9G8, and hrp45/SRp55 cosediment with monoribosomes. Thus, individual endogenous pre-mRNPs/mRNPs bind multiple types of SR proteins during transcription, and these SR proteins accompany the mRNA and play different roles during the gene expression pathway in vivo.
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Affiliation(s)
- Petra Björk
- Department of Molecular Biology and Functional Genomics and Department of Mathematics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - ShaoBo Jin
- Department of Molecular Biology and Functional Genomics and Department of Mathematics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Jian Zhao
- Department of Molecular Biology and Functional Genomics and Department of Mathematics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Om Prakash Singh
- Department of Molecular Biology and Functional Genomics and Department of Mathematics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Jan-Olov Persson
- Department of Molecular Biology and Functional Genomics and Department of Mathematics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ulf Hellman
- Ludwig Institute for Cancer Research, SE-751 24 Uppsala, Sweden
| | - Lars Wieslander
- Department of Molecular Biology and Functional Genomics and Department of Mathematics, Stockholm University, SE-106 91 Stockholm, Sweden
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38
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Identification of B52-dependent Gene Expression Signature and Alternative Splicing Using a D. melanogaster B52-null Mutant. B KOREAN CHEM SOC 2009. [DOI: 10.5012/bkcs.2009.30.2.323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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39
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Abstract
The SR protein family comprises a number of phylogenetically conserved and structurally related proteins with a characteristic domain rich in arginine and serine residues, known as the RS domain. They play significant roles in constitutive pre-mRNA splicing and are also important regulators of alternative splicing. In addition they participate in post-splicing activities, such as mRNA nuclear export, nonsense-mediated mRNA decay and mRNA translation. These wide-ranging roles of SR proteins highlight their importance as pivotal regulators of mRNA metabolism, and if these functions are disrupted, developmental defects or disease may result. Furthermore, animal models have shown a highly specific, non-redundant role for individual SR proteins in the regulation of developmental processes. Here, we will review the current literature to demonstrate how SR proteins are emerging as one of the master regulators of gene expression.
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40
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Barr AR, Zyss D, Gergely F. Knock-in and knock-out: the use of reverse genetics in somatic cells to dissect mitotic pathways. Methods Mol Biol 2009; 545:1-19. [PMID: 19475379 DOI: 10.1007/978-1-60327-993-2_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Reverse genetic methods, such as homologous gene targeting, have greatly contributed to our understanding of molecular pathways in mitosis, especially in yeast. The chicken B-lymphocyte line, DT40, represents a unique example among vertebrate somatic cells where homologous gene targeting occurs at very high frequency. DT40 cells therefore provide a useful and accessible somatic genetic system for wide-ranging biochemical and cell biological assays. In this chapter, we describe the main principles of homologous gene targeting, the concept of targeting construct design and the detailed experimental protocol of how to achieve successful knockouts. We also mention methods for conditional disruption of essential genes and conclude with specific procedures for the study of mitosis in DT40 cells.
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Affiliation(s)
- Alexis R Barr
- Department of Oncology, Cancer Research UK Cambridge Research Institute, University of Cambridge, Cambridge, UK
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41
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Sanford JR, Wang X, Mort M, Vanduyn N, Cooper DN, Mooney SD, Edenberg HJ, Liu Y. Splicing factor SFRS1 recognizes a functionally diverse landscape of RNA transcripts. Genome Res 2008; 19:381-94. [PMID: 19116412 DOI: 10.1101/gr.082503.108] [Citation(s) in RCA: 240] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Metazoan genes are encrypted with at least two superimposed codes: the genetic code to specify the primary structure of proteins and the splicing code to expand their proteomic output via alternative splicing. Here, we define the specificity of a central regulator of pre-mRNA splicing, the conserved, essential splicing factor SFRS1. Cross-linking immunoprecipitation and high-throughput sequencing (CLIP-seq) identified 23,632 binding sites for SFRS1 in the transcriptome of cultured human embryonic kidney cells. SFRS1 was found to engage many different classes of functionally distinct transcripts including mRNA, miRNA, snoRNAs, ncRNAs, and conserved intergenic transcripts of unknown function. The majority of these diverse transcripts share a purine-rich consensus motif corresponding to the canonical SFRS1 binding site. The consensus site was not only enriched in exons cross-linked to SFRS1 in vivo, but was also enriched in close proximity to splice sites. mRNAs encoding RNA processing factors were significantly overrepresented, suggesting that SFRS1 may broadly influence the post-transcriptional control of gene expression in vivo. Finally, a search for the SFRS1 consensus motif within the Human Gene Mutation Database identified 181 mutations in 82 different genes that disrupt predicted SFRS1 binding sites. This comprehensive analysis substantially expands the known roles of human SR proteins in the regulation of a diverse array of RNA transcripts.
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Affiliation(s)
- Jeremy R Sanford
- Department of Molecular, Cellular, and Developmental Biology, University of California Santa Cruz, Santa Cruz, California 95064, USA.
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42
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Merdzhanova G, Edmond V, De Seranno S, Van den Broeck A, Corcos L, Brambilla C, Brambilla E, Gazzeri S, Eymin B. E2F1 controls alternative splicing pattern of genes involved in apoptosis through upregulation of the splicing factor SC35. Cell Death Differ 2008; 15:1815-23. [DOI: 10.1038/cdd.2008.135] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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43
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Lin S, Coutinho-Mansfield G, Wang D, Pandit S, Fu XD. The splicing factor SC35 has an active role in transcriptional elongation. Nat Struct Mol Biol 2008; 15:819-26. [PMID: 18641664 PMCID: PMC2574591 DOI: 10.1038/nsmb.1461] [Citation(s) in RCA: 287] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Accepted: 06/13/2008] [Indexed: 12/24/2022]
Abstract
Mounting evidence suggests that transcription and RNA processing are intimately coupled in vivo, although each process can occur independently in vitro. It is generally thought that polymerase II (Pol II) C-terminal domain (CTD) kinases are recruited near the transcription start site to overcome initial Pol II pausing events, and that stably bound kinases facilitate productive elongation and co-transcriptional RNA processing. Whereas most studies have focused on how RNA processing machineries take advantage of the transcriptional apparatus to efficiently modify nascent RNA, here we report that a well-studied splicing factor, SC35, affects transcriptional elongation in a gene-specific manner. SC35 depletion induces Pol II accumulation within the gene body and attenuated elongation, which are correlated with defective P-TEFb (a complex composed of CycT1-CDK9) recruitment and dramatically reduced CTD Ser2 phosphorylation. Recombinant SC35 is sufficient to rescue this defect in nuclear run-on experiments. These findings suggest a reciprocal functional relationship between the transcription and splicing machineries during gene expression.
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Affiliation(s)
- Shengrong Lin
- Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0651, USA
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44
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Mirkin N, Fonseca D, Mohammed S, Cevher MA, Manley JL, Kleiman FE. The 3' processing factor CstF functions in the DNA repair response. Nucleic Acids Res 2008; 36:1792-804. [PMID: 18252771 PMCID: PMC2330234 DOI: 10.1093/nar/gkn005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Following DNA damage, mRNA levels decrease, reflecting a coordinated interaction of the DNA repair, transcription and RNA processing machineries. In this study, we provide evidence that transcription and polyadenylation of mRNA precursors are both affected in vivo by UV treatment. We next show that the polyadenylation factor CstF, plays a direct role in the DNA damage response. Cells with reduced levels of CstF display decreased viability following UV treatment, reduced ability to ubiquitinate RNA polymerase II (RNAP II), and defects in repair of DNA damage. Furthermore, we show that CstF, RNAP II and BARD1 are all found at sites of repaired DNA. Our results indicate that CstF plays an active role in the response to DNA damage, providing a link between transcription-coupled RNA processing and DNA repair.
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Affiliation(s)
- Nurit Mirkin
- Chemistry Department, Hunter College, City University of New York, New York, NY 10027, USA
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45
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Inaki M, Utsugi T, Onoda F, Hanaoka F, Murakami Y. A novel class of temperature-sensitive mutants generated by RNAi-mediated knockdown. Biochem Biophys Res Commun 2008; 365:472-7. [PMID: 17991422 DOI: 10.1016/j.bbrc.2007.10.185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Accepted: 10/30/2007] [Indexed: 12/01/2022]
Abstract
Temperature-sensitive (ts) mutants are powerful tools with which to investigate gene function, but it has been difficult to generate ts mutants in mammalian cells. Recently, RNA interference (RNAi) has been widely used for loss of function analyses. In addition, in various organisms, hypothermic-temperature-sensitive RNAi has been reported. By using this characteristic of RNAi, we attempted to generate ts mutants in mammalian cells and were able to successfully generate ts mutants of cell cycle regulator cdc2 and ubiquitin-activating enzyme E1. We compared ts mutants previously isolated by mutagenesis with those generated by RNAi knockdown, and observed similar phenotypes. This method enabled us to generate ts mutants (KDts, knockdown temperature-sensitive mutants) of the genes of interest and will be utilized to facilitate understanding of the biological processes regulated by an essential gene in mammalian cells.
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Affiliation(s)
- Makoto Inaki
- Genome and Drug Research Center, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
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46
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Li X, Niu T, Manley JL. The RNA binding protein RNPS1 alleviates ASF/SF2 depletion-induced genomic instability. RNA (NEW YORK, N.Y.) 2007; 13:2108-2115. [PMID: 17959926 PMCID: PMC2080599 DOI: 10.1261/rna.734407] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 09/11/2007] [Indexed: 05/25/2023]
Abstract
Formation of transcription-induced R-loops poses a critical threat to genomic integrity throughout evolution. We have recently shown that the SR protein ASF/SF2 prevents R-loop formation in vertebrates by cotranscriptionally binding to nascent mRNA precursors to prevent their reassociation with template DNA. Here, we identify another RNA binding protein, RNPS1, that when overexpressed strongly suppresses the high molecular weight (HMW) DNA fragmentation, hypermutation, and G2 cell cycle arrest phenotypes of ASF/SF2-depleted cells. Furthermore, ablation of RNPS1 by RNA interference in HeLa cells leads to accumulation of HMW DNA fragments. As ASF/SF2 depletion does not influence RNPS1 expression, and RNPS1 cannot compensate for ASF/SF2 function in splicing, our data suggest that RNPS1 is able to function together with ASF/SF2 to form RNP complexes on nascent transcripts, and thereby prevent formation of transcriptional R-loops.
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Affiliation(s)
- Xialu Li
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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47
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Variations in intracellular levels of TATA binding protein can affect specific genes by different mechanisms. Mol Cell Biol 2007; 28:83-92. [PMID: 17954564 DOI: 10.1128/mcb.00809-07] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously showed that reduced intracellular levels of the TATA binding protein (TBP), brought about by tbp heterozygosity in DT40 cells, resulted in a mitotic delay reflecting reduced expression of the mitotic regulator cdc25B but did not significantly affect overall transcription. Here we extend these findings in several ways. We first provide evidence that the decrease in cdc25B expression reflects reduced activity of the cdc25B core promoter in the heterozygous (TBP-het) cells. Strikingly, mutations in a previously described repressor element that overlaps the TATA box restored promoter activity in TBP-het cells, supporting the idea that the sensitivity of this promoter to TBP levels reflects a competition between TBP and the repressor for DNA binding. To determine whether cells might have mechanisms to compensate for fluctuations in TBP levels, we next examined expression of the two known vertebrate TBP homologues, TLP and TBP2. Significantly, mRNAs encoding both were significantly overexpressed relative to levels observed in wild-type cells. In the case of TLP, this was shown to reflect regulation of the core promoter by both TBP and TLP. Together, our results indicate that variations in TBP levels can affect the transcription of specific promoters in distinct ways, but overall transcription may be buffered by corresponding alterations in the expression of TBP homologues.
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48
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Möröy T, Heyd F. The impact of alternative splicing in vivo: mouse models show the way. RNA (NEW YORK, N.Y.) 2007; 13:1155-71. [PMID: 17563071 PMCID: PMC1924907 DOI: 10.1261/rna.554607] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Alternative splicing is widely believed to have a major impact on almost all biological processes since it increases proteome complexity and thereby controls protein function. Recently, gene targeting in mice has been used to create in vivo models to study the regulation and consequences of alternative splicing. The evidence accumulated so far argues for a nonredundant, highly specific role of individual splicing factors in mammalian development, and furthermore, demonstrates the importance of distinct protein isoforms in vivo. In this review, we will compare phenotypes of mouse models for alternative splicing to crystallize common themes and to put them into perspective with the available in vitro data.
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Affiliation(s)
- Tarik Möröy
- Institut de Recherches Cliniques de Montréal, IRCM, Montréal, QC, Canada.
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49
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Xiao R, Sun Y, Ding JH, Lin S, Rose DW, Rosenfeld MG, Fu XD, Li X. Splicing regulator SC35 is essential for genomic stability and cell proliferation during mammalian organogenesis. Mol Cell Biol 2007; 27:5393-402. [PMID: 17526736 PMCID: PMC1952092 DOI: 10.1128/mcb.00288-07] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 03/30/2007] [Accepted: 05/15/2007] [Indexed: 11/20/2022] Open
Abstract
The members of the SR family of splicing regulators were initially characterized for their critical roles in constitutive and regulated splicing. They are implicated in different aspects of gene expression processes, including transcription, RNA stability, mRNA transport, and translational control. While knockout studies have demonstrated their essential functions during animal development, the pathway(s) leading to a specific cellular phenotype remains poorly understood. We report here that the SR protein SC35 controls cell proliferation during pituitary gland development but is completely dispensable in terminal differentiated mature cardiomyocytes in mice. We show that loss of SC35 in mouse embryonic fibroblasts induces G2/M cell cycle arrest and genomic instability, resulting at least in part from p53 hyperphosphorylation and hyperacetylation. While p53 hyperphosphorylation appears related to ATM activation, its hyperacetylation has been attributed to the increased expression of the acetyltransferase gene p300 and the aberrant splicing of the deacetylase gene SirT1. These findings reveal the involvement of SC35 in specific pathways in regulating cell proliferation and genomic stability during mammalian organogenesis and suggest its potential function in tumorigenesis.
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Affiliation(s)
- Ran Xiao
- Department of Surgery/Urology, Children's Hospital of Boston, Harvard Medical School, 300 Longwood Ave., Boston, MA 02115, USA
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50
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Patwardhan P, Miller WT. Processive phosphorylation: mechanism and biological importance. Cell Signal 2007; 19:2218-26. [PMID: 17644338 PMCID: PMC2034209 DOI: 10.1016/j.cellsig.2007.06.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Revised: 05/31/2007] [Accepted: 06/12/2007] [Indexed: 01/13/2023]
Abstract
Recent proteomic data indicate that a majority of the phosphorylated proteins in a eucaryotic cell contain multiple sites of phosphorylation. In many signaling events, a single kinase phosphorylates multiple sites on a target protein. Processive phosphorylation occurs when a protein kinase binds once to a substrate and phosphorylates all of the available sites before dissociating. In this review, we discuss examples of processive phosphorylation by serine/threonine kinases and tyrosine kinases. We describe current experimental approaches for distinguishing processive from non-processive phosphorylation. Finally, we contrast the biological situations that are suited to regulation by processive and non-processive phosphorylation.
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Affiliation(s)
- Parag Patwardhan
- Department of Physiology and Biophysics, School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
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