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Zhan X, Lu Y, Shi Y. Molecular basis for the activation of human spliceosome. Nat Commun 2024; 15:6348. [PMID: 39068178 PMCID: PMC11283556 DOI: 10.1038/s41467-024-50785-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Accepted: 07/20/2024] [Indexed: 07/30/2024] Open
Abstract
The spliceosome executes pre-mRNA splicing through four sequential stages: assembly, activation, catalysis, and disassembly. Activation of the spliceosome, namely remodeling of the pre-catalytic spliceosome (B complex) into the activated spliceosome (Bact complex) and the catalytically activated spliceosome (B* complex), involves major flux of protein components and structural rearrangements. Relying on a splicing inhibitor, we have captured six intermediate states between the B and B* complexes: pre-Bact, Bact-I, Bact-II, Bact-III, Bact-IV, and post-Bact. Their cryo-EM structures, together with an improved structure of the catalytic step I spliceosome (C complex), reveal how the catalytic center matures around the internal stem loop of U6 snRNA, how the branch site approaches 5'-splice site, how the RNA helicase PRP2 rearranges to bind pre-mRNA, and how U2 snRNP undergoes remarkable movement to facilitate activation. We identify a previously unrecognized key role of PRP2 in spliceosome activation. Our study recapitulates a molecular choreography of the human spliceosome during its catalytic activation.
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Affiliation(s)
- Xiechao Zhan
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China.
- Research Center for Industries of the Future, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China.
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China.
| | - Yichen Lu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- Research Center for Industries of the Future, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
- College of Life Sciences, Fudan University, Shanghai, China
| | - Yigong Shi
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China.
- Research Center for Industries of the Future, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China.
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China.
- Beijing Frontier Research Center for Biological Structure, Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China.
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2
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Ciampi L, Serrano L, Irimia M. Unique transcriptomes of sensory and non-sensory neurons: insights from Splicing Regulatory States. Mol Syst Biol 2024; 20:296-310. [PMID: 38438733 PMCID: PMC10987577 DOI: 10.1038/s44320-024-00020-1] [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: 10/31/2023] [Revised: 01/04/2024] [Accepted: 01/12/2024] [Indexed: 03/06/2024] Open
Abstract
Alternative Splicing (AS) programs serve as instructive signals of cell type specificity, particularly within the brain, which comprises dozens of molecularly and functionally distinct cell types. Among them, retinal photoreceptors stand out due to their unique transcriptome, making them a particularly well-suited system for studying how AS shapes cell type-specific molecular functions. Here, we use the Splicing Regulatory State (SRS) as a novel framework to discuss the splicing factors governing the unique AS pattern of photoreceptors, and how this pattern may aid in the specification of their highly specialized sensory cilia. In addition, we discuss how other sensory cells with ciliated structures, for which data is much scarcer, also rely on specific SRSs to implement a proteome specialized in the detection of sensory stimuli. By reviewing the general rules of cell type- and tissue-specific AS programs, firstly in the brain and subsequently in specialized sensory neurons, we propose a novel paradigm on how SRSs are established and how they can diversify. Finally, we illustrate how SRSs shape the outcome of mutations in splicing factors to produce cell type-specific phenotypes that can lead to various human diseases.
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Affiliation(s)
- Ludovica Ciampi
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.
| | - Luis Serrano
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.
- Universitat Pompeu Fabra, Barcelona, Spain.
- ICREA, Barcelona, Spain.
| | - Manuel Irimia
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.
- Universitat Pompeu Fabra, Barcelona, Spain.
- ICREA, Barcelona, Spain.
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3
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Zhang T, Xu L, Zhu H, Ying Y, Ding J, Ding H, Shi X, He Y, Jin X, Xia G. Familial and genetic association with neurodevelopmental disorders caused by a heterozygous variant in the SRRM2 gene. Front Endocrinol (Lausanne) 2023; 14:1240168. [PMID: 37621647 PMCID: PMC10445754 DOI: 10.3389/fendo.2023.1240168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 07/13/2023] [Indexed: 08/26/2023] Open
Abstract
Background Neurodevelopmental disorders (NDDs) are a class of disorders affecting brain development and function, characterized by an inability to reach cognitive, emotional, and motor developmental milestones. The pathology of NDDs is complex. A recent study found that variants in the SRRM2 gene cause NDDs. However, genetic conditions play the most important role in the etiology of NDD. The genetic causes of NDD are extremely heterogeneous, leading to certain challenges in clinical diagnosis. Methods A pregnant woman with congenital intelligence disorder came to our hospital for genetic diagnosis to predict the status of her fetus. Her mother and a brother also suffer from congenital intelligence disorder. She has a daughter with speech delay. Whole exome sequencing was used to identify a mutation (c.1415C>G) in the SRRM2 gene of this family that resulted in a change in the 472nd amino acid residue of the SRRM2 protein from serine to terminated. Conclusion We report a family with an autosomal dominant genetic disorder caused by variants in the SRRM2 gene causing NDDs. Prenatal diagnosis can help patients with this genetic disorder to have healthy offspring.
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Affiliation(s)
- Tao Zhang
- Shaoxing Maternity and Child Health Care Hospital, Shaoxing, Zhejiang, China
- Obstetrics and Gynecology Hospital of Shaoxing University, Shaoxing, Zhejiang, China
| | - Lei Xu
- Obstetrics and Gynecology Hospital of Shaoxing University, Shaoxing, Zhejiang, China
- Shaoxing University, Shaoxing, Zhejiang, China
| | - Hongdan Zhu
- Shaoxing Maternity and Child Health Care Hospital, Shaoxing, Zhejiang, China
- Obstetrics and Gynecology Hospital of Shaoxing University, Shaoxing, Zhejiang, China
| | - Yuyi Ying
- Shaoxing Maternity and Child Health Care Hospital, Shaoxing, Zhejiang, China
- Obstetrics and Gynecology Hospital of Shaoxing University, Shaoxing, Zhejiang, China
| | - Jinlong Ding
- Shaoxing Maternity and Child Health Care Hospital, Shaoxing, Zhejiang, China
- Obstetrics and Gynecology Hospital of Shaoxing University, Shaoxing, Zhejiang, China
| | - Haigang Ding
- Shaoxing Maternity and Child Health Care Hospital, Shaoxing, Zhejiang, China
- Obstetrics and Gynecology Hospital of Shaoxing University, Shaoxing, Zhejiang, China
| | - Xiaoliang Shi
- Shaoxing Maternity and Child Health Care Hospital, Shaoxing, Zhejiang, China
- Obstetrics and Gynecology Hospital of Shaoxing University, Shaoxing, Zhejiang, China
| | - Yao He
- Shaoxing Maternity and Child Health Care Hospital, Shaoxing, Zhejiang, China
- Obstetrics and Gynecology Hospital of Shaoxing University, Shaoxing, Zhejiang, China
| | - Xin Jin
- Obstetrics and Gynecology Hospital of Shaoxing University, Shaoxing, Zhejiang, China
- Shaoxing University, Shaoxing, Zhejiang, China
| | - Guiyu Xia
- Shaoxing Maternity and Child Health Care Hospital, Shaoxing, Zhejiang, China
- Obstetrics and Gynecology Hospital of Shaoxing University, Shaoxing, Zhejiang, China
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4
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Liu Z, Sun J, Quan J, Li L, Zhao G, Lu J. Effect of selenium nanoparticles on alternative splicing in heat-stressed rainbow trout primary hepatocytes. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2023; 45:101042. [PMID: 36455514 DOI: 10.1016/j.cbd.2022.101042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 11/04/2022] [Accepted: 11/19/2022] [Indexed: 11/25/2022]
Abstract
Alternative splicing (AS) is a ubiquitous post-transcriptional regulatory mechanism in eukaryotes that generates multiple mRNA isoforms from a single gene, increasing diversity of mRNAs and proteins that are essential for eukaryotic developmental processes and responses to environmental stress. Results showed that a total of 37,463 AS events were identified in rainbow trout hepatocytes. In addition, a total of 364 differential alternative splicing (DAS) events were identified in hepatocytes under selenium nanoparticles (SeNPs) and 3632 DAS events were identified under a combination of SeNPs and heat stress (24 °C). Gene Ontology (GO) enrichment showed that some subcategories "immune effector processes", "response to stimuli" and "antioxidant activity" were associated with immunity, abiotic stimuli and antioxidants. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment showed that differentially expressed genes (DEGs) were significantly enriched in spliceosomes by adding SeNPs in heat-stressed hepatocytes. Splicing factor family (SRSF3, SRSF7, SRSF9, U2AF1 and U2AF2) and pre-RNA splicing factors (ACIN1 and PPRF18) were significantly upregulated and promoted AS. Furthermore, addition of SeNPs activated the phosphatidylinositol signaling system and upregulated the related genes PI4KA, DGKH, ITPK1 and Ocrl, and thus attenuated the inflammatory response to heat stress and enhanced resistance to heat stress by activating the adherent plaque kinase-PI3K-Akt signaling pathway and calcium channels. Those findings suggested that AS could be an essential regulatory mechanism in adaptation of rainbow trout to heat-stressed environments.
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Affiliation(s)
- Zhe Liu
- College of Animal Science and Technology, Gansu Agricultural University, No. 1, Yingmen Village, Anning District, Lanzhou City, Gansu Province 730070, PR China.
| | - Jun Sun
- College of Animal Science and Technology, Gansu Agricultural University, No. 1, Yingmen Village, Anning District, Lanzhou City, Gansu Province 730070, PR China
| | - Jinqiang Quan
- College of Animal Science and Technology, Gansu Agricultural University, No. 1, Yingmen Village, Anning District, Lanzhou City, Gansu Province 730070, PR China
| | - Lanlan Li
- College of Animal Science and Technology, Gansu Agricultural University, No. 1, Yingmen Village, Anning District, Lanzhou City, Gansu Province 730070, PR China
| | - Guiyan Zhao
- College of Animal Science and Technology, Gansu Agricultural University, No. 1, Yingmen Village, Anning District, Lanzhou City, Gansu Province 730070, PR China
| | - Junhao Lu
- College of Animal Science and Technology, Gansu Agricultural University, No. 1, Yingmen Village, Anning District, Lanzhou City, Gansu Province 730070, PR China
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5
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Ilık İA, Aktaş T. Nuclear speckles: dynamic hubs of gene expression regulation. FEBS J 2022; 289:7234-7245. [PMID: 34245118 DOI: 10.1111/febs.16117] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/13/2021] [Accepted: 07/08/2021] [Indexed: 01/13/2023]
Abstract
Complex, multistep biochemical reactions that routinely take place in our cells require high concentrations of enzymes, substrates, and other structural components to proceed efficiently and typically require chemical environments that can inhibit other reactions in their immediate vicinity. Eukaryotic cells solve these problems by restricting such reactions into diffusion-restricted compartments within the cell called organelles that can be separated from their environment by a lipid membrane, or into membrane-less compartments that form through liquid-liquid phase separation (LLPS). One of the most easily noticeable and the earliest discovered organelle is the nucleus, which harbors the genetic material in cells where transcription by RNA polymerases produces most of the messenger RNAs and a plethora of noncoding RNAs, which in turn are required for translation of mRNAs in the cytoplasm. The interior of the nucleus is not a uniform soup of biomolecules and rather consists of a variety of membrane-less bodies, such as the nucleolus, nuclear speckles (NS), paraspeckles, Cajal bodies, histone locus bodies, and more. In this review, we will focus on NS with an emphasis on recent developments including our own findings about the formation of NS by two large IDR-rich proteins SON and SRRM2.
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Affiliation(s)
| | - Tuğçe Aktaş
- Max Planck Institute for Molecular Genetics, Berlin, Germany
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6
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Xu S, Lai SK, Sim DY, Ang W, Li HY, Roca X. SRRM2 organizes splicing condensates to regulate alternative splicing. Nucleic Acids Res 2022; 50:8599-8614. [PMID: 35929045 PMCID: PMC9410892 DOI: 10.1093/nar/gkac669] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/29/2022] [Accepted: 08/04/2022] [Indexed: 12/27/2022] Open
Abstract
SRRM2 is a nuclear-speckle marker containing multiple disordered domains, whose dysfunction is associated with several human diseases. Using mainly EGFP-SRRM2 knock-in HEK293T cells, we show that SRRM2 forms biomolecular condensates satisfying most hallmarks of liquid-liquid phase separation, including spherical shape, dynamic rearrangement, coalescence and concentration dependence supported by in vitro experiments. Live-cell imaging shows that SRRM2 organizes nuclear speckles along the cell cycle. As bona-fide splicing factor present in spliceosome structures, SRRM2 deficiency induces skipping of cassette exons with short introns and weak splice sites, tending to change large protein domains. In THP-1 myeloid-like cells, SRRM2 depletion compromises cell viability, upregulates differentiation markers, and sensitizes cells to anti-leukemia drugs. SRRM2 induces a FES splice isoform that attenuates innate inflammatory responses, and MUC1 isoforms that undergo shedding with oncogenic properties. We conclude that SRRM2 acts as a scaffold to organize nuclear speckles, regulating alternative splicing in innate immunity and cell homeostasis.
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Affiliation(s)
- Shaohai Xu
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - Soak-Kuan Lai
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - Donald Yuhui Sim
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | | | - Hoi Yeung Li
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - Xavier Roca
- To whom correspondence should be addressed. Tel: +65 65927561;
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7
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Cuinat S, Nizon M, Isidor B, Stegmann A, van Jaarsveld RH, van Gassen KL, van der Smagt JJ, Volker-Touw CML, Holwerda SJB, Terhal PA, Schuhmann S, Vasileiou G, Khalifa M, Nugud AA, Yasaei H, Ousager LB, Brasch-Andersen C, Deb W, Besnard T, Simon MEH, Amsterdam KHV, Verbeek NE, Matalon D, Dykzeul N, White S, Spiteri E, Devriendt K, Boogaerts A, Willemsen M, Brunner HG, Sinnema M, De Vries BBA, Gerkes EH, Pfundt R, Izumi K, Krantz ID, Xu ZL, Murrell JR, Valenzuela I, Cusco I, Rovira-Moreno E, Yang Y, Bizaoui V, Patat O, Faivre L, Tran-Mau-Them F, Vitobello A, Denommé-Pichon AS, Philippe C, Bezieau S, Cogné B. Loss-of-function variants in SRRM2 cause a neurodevelopmental disorder. Genet Med 2022; 24:1774-1780. [PMID: 35567594 DOI: 10.1016/j.gim.2022.04.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 04/06/2022] [Accepted: 04/06/2022] [Indexed: 10/18/2022] Open
Abstract
PURPOSE SRRM2 encodes the SRm300 protein, a splicing factor of the SR-related protein family characterized by its serine- and arginine-enriched domains. It promotes interactions between messenger RNA and the spliceosome catalytic machinery. This gene, predicted to be highly intolerant to loss of function (LoF) and very conserved through evolution, has not been previously reported in constitutive human disease. METHODS Among the 1000 probands studied with developmental delay and intellectual disability in our database, we found 2 patients with de novo LoF variants in SRRM2. Additional families were identified through GeneMatcher. RESULTS Here, we report on 22 patients with LoF variants in SRRM2 and provide a description of the phenotype. Molecular analysis identified 12 frameshift variants, 8 nonsense variants, and 2 microdeletions of 66 kb and 270 kb. The patients presented with a mild developmental delay, predominant speech delay, autistic or attention-deficit/hyperactivity disorder features, overfriendliness, generalized hypotonia, overweight, and dysmorphic facial features. Intellectual disability was variable and mild when present. CONCLUSION We established SRRM2 as a gene responsible for a rare neurodevelopmental disease.
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Affiliation(s)
- Silvestre Cuinat
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, France.
| | - Mathilde Nizon
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, France; Université de Nantes, Inserm UMR 1087 / CNRS UMR 6291, Institut du thorax, Nantes, France
| | - Bertrand Isidor
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, France; Université de Nantes, Inserm UMR 1087 / CNRS UMR 6291, Institut du thorax, Nantes, France
| | - Alexander Stegmann
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | | | - Koen L van Gassen
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | | | - Sjoerd J B Holwerda
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Paulien A Terhal
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Sarah Schuhmann
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Georgia Vasileiou
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Mohamed Khalifa
- Genetic Department, Dubai Health Authority, Latifa Women and Children Hospital, Dubai, United Arab Emirates
| | - Alaa A Nugud
- Genetic Department, Dubai Health Authority, Latifa Women and Children Hospital, Dubai, United Arab Emirates
| | - Hemad Yasaei
- Dubai Genetics Center, Pathology and Genetics Department, Dubai Health Authority, Dubai, United Arab Emirates
| | - Lilian Bomme Ousager
- Department of Clinical Genetics & Human Genetics, Odense University Hospital, University of Southern Denmark, Odense, Denmark; Department of Clinical Research, Odense University Hospital, University of Southern Denmark, Odense, Denmark
| | - Charlotte Brasch-Andersen
- Department of Clinical Genetics & Human Genetics, Odense University Hospital, University of Southern Denmark, Odense, Denmark; Department of Clinical Research, Odense University Hospital, University of Southern Denmark, Odense, Denmark
| | - Wallid Deb
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, France; Université de Nantes, Inserm UMR 1087 / CNRS UMR 6291, Institut du thorax, Nantes, France
| | - Thomas Besnard
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, France; Université de Nantes, Inserm UMR 1087 / CNRS UMR 6291, Institut du thorax, Nantes, France
| | - Marleen E H Simon
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Nienke E Verbeek
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dena Matalon
- Department of Pediatric, Division of Medical Genetics, Stanford University and Health Care, Palo Alto, CA
| | - Natalie Dykzeul
- Department of Pediatric, Division of Medical Genetics, Stanford University and Health Care, Palo Alto, CA
| | - Shana White
- Department of Pediatric, Division of Medical Genetics, Stanford University and Health Care, Palo Alto, CA
| | - Elizabeth Spiteri
- Department of Pediatric, Division of Medical Genetics, Stanford University and Health Care, Palo Alto, CA
| | - Koen Devriendt
- Center for Human Genetics, University Hospital Leuven, KU Leuven, O&N I Herestraat 49, Leuven, Belgium
| | - Anneleen Boogaerts
- Center for Human Genetics, University Hospital Leuven, KU Leuven, O&N I Herestraat 49, Leuven, Belgium
| | - Marjolein Willemsen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Han G Brunner
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Margje Sinnema
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Bert B A De Vries
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Erica H Gerkes
- University Medical Center Groningen, Department of Genetics, University of Groningen, Groningen, The Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kosuke Izumi
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Ian D Krantz
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Zhou L Xu
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Jill R Murrell
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Irene Valenzuela
- Department of Clinical and Molecular Genetics, Hospital Vall d'Hebron, Barcelona, Spain
| | - Ivon Cusco
- Department of Clinical and Molecular Genetics, Hospital Vall d'Hebron, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Spain
| | - Eulàlia Rovira-Moreno
- Department of Clinical and Molecular Genetics, Hospital Vall d'Hebron, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Spain
| | | | - Varoona Bizaoui
- Clinical Genetics and Neurodevelopmental Disorders, Centre Hospitalier de l'Estran, Pontorson, France
| | - Olivier Patat
- Department of Medical Genetics, Toulouse University Hospital, Toulouse, France
| | - Laurence Faivre
- Centre de référence Anomalies du Développement et Syndromes malformatifs, FHU-TRANSLAD, GAD, CHU Dijon et Université de Bourgogne, Dijon, France; Inserm UMR1231, GAD, Université de Bourgogne, Dijon, France
| | - Frederic Tran-Mau-Them
- Unité Fonctionnelle Innovation en Diagnostic Génomique des Maladies Rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France; Inserm UMR1231, GAD, Université de Bourgogne, Dijon, France
| | - Antonio Vitobello
- Unité Fonctionnelle Innovation en Diagnostic Génomique des Maladies Rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France; Inserm UMR1231, GAD, Université de Bourgogne, Dijon, France
| | - Anne-Sophie Denommé-Pichon
- Unité Fonctionnelle Innovation en Diagnostic Génomique des Maladies Rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France; Inserm UMR1231, GAD, Université de Bourgogne, Dijon, France
| | - Christophe Philippe
- Unité Fonctionnelle Innovation en Diagnostic Génomique des Maladies Rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France; Inserm UMR1231, GAD, Université de Bourgogne, Dijon, France
| | - Stéphane Bezieau
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, France; Université de Nantes, Inserm UMR 1087 / CNRS UMR 6291, Institut du thorax, Nantes, France
| | - Benjamin Cogné
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, France; Université de Nantes, Inserm UMR 1087 / CNRS UMR 6291, Institut du thorax, Nantes, France.
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8
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Chatenoud L, Marquet C, Valette F, Scott L, Quan J, Bu CH, Hildebrand S, Moresco EMY, Bach JF, Beutler B. Modulation of autoimmune diabetes by N-ethyl-N-nitrosourea- induced mutations in non-obese diabetic mice. Dis Model Mech 2022; 15:275575. [PMID: 35502705 PMCID: PMC9178510 DOI: 10.1242/dmm.049484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/21/2022] [Indexed: 11/20/2022] Open
Abstract
Genetic association studies of type 1 diabetes (T1D) in humans, and in congenic non-obese diabetic (NOD) mice harboring DNA segments from T1D-resistant mice, face the challenge of assigning causation to specific gene variants among many within loci that affect disease risk. Here, we created random germline mutations in NOD/NckH mice and used automated meiotic mapping to identify mutations modifying T1D incidence and age of onset. In contrast with association studies in humans or congenic NOD mice, we analyzed a relatively small number of genetic changes in each pedigree, permitting implication of specific mutations as causative. Among 844 mice from 14 pedigrees bearing 594 coding/splicing changes, we identified seven mutations that accelerated T1D development, and five that delayed or suppressed T1D. Eleven mutations affected genes not previously known to influence T1D (Xpnpep1, Herc1, Srrm2, Rapgef1, Ppl, Zfp583, Aldh1l1, Col6a1, Ccdc13, Cd200r1, Atrnl1). A suppressor mutation in Coro1a validated the screen. Mutagenesis coupled with automated meiotic mapping can detect genes in which allelic variation influences T1D susceptibility in NOD mice. Variation of some of the orthologous/paralogous genes may influence T1D susceptibility in humans.
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Affiliation(s)
- Lucienne Chatenoud
- Université Paris Cité, Institut Necker Enfants Malades, F-75015 Paris, France.,INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, F-75015 Paris, France
| | - Cindy Marquet
- Université Paris Cité, Institut Necker Enfants Malades, F-75015 Paris, France.,INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, F-75015 Paris, France
| | - Fabrice Valette
- Université Paris Cité, Institut Necker Enfants Malades, F-75015 Paris, France.,INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, F-75015 Paris, France
| | - Lindsay Scott
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jiexia Quan
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Chun Hui Bu
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sara Hildebrand
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Eva Marie Y Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jean-François Bach
- Université Paris Cité, Institut Necker Enfants Malades, F-75015 Paris, France.,INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, F-75015 Paris, France
| | - Bruce Beutler
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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9
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Near Chromosome-Level Genome Assembly and Annotation of Rhodotorula babjevae Strains Reveals High Intraspecific Divergence. J Fungi (Basel) 2022; 8:jof8040323. [PMID: 35448555 PMCID: PMC9027234 DOI: 10.3390/jof8040323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 03/16/2022] [Accepted: 03/19/2022] [Indexed: 02/04/2023] Open
Abstract
The genus Rhodotorula includes basidiomycetous oleaginous yeast species. Rhodotorula babjevae can produce compounds of biotechnological interest such as lipids, carotenoids, and biosurfactants from low value substrates such as lignocellulose hydrolysate. High-quality genome assemblies are needed to develop genetic tools and to understand fungal evolution and genetics. Here, we combined short- and long-read sequencing to resolve the genomes of two R. babjevae strains, CBS 7808 (type strain) and DBVPG 8058, at chromosomal level. Both genomes are 21 Mbp in size and have a GC content of 68.2%. Allele frequency analysis indicates that both strains are tetraploid. The genomes consist of a maximum of 21 chromosomes with a size of 0.4 to 2.4 Mbp. In both assemblies, the mitochondrial genome was recovered in a single contig, that shared 97% pairwise identity. Pairwise identity between most chromosomes ranges from 82 to 87%. We also found indications for strain-specific extrachromosomal endogenous DNA. A total of 7591 and 7481 protein-coding genes were annotated in CBS 7808 and DBVPG 8058, respectively. CBS 7808 accumulated a higher number of tandem duplications than DBVPG 8058. We identified large translocation events between putative chromosomes. Genome divergence values between the two strains indicate that they may belong to different species.
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10
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Lester E, Ooi FK, Bakkar N, Ayers J, Woerman AL, Wheeler J, Bowser R, Carlson GA, Prusiner SB, Parker R. Tau aggregates are RNA-protein assemblies that mislocalize multiple nuclear speckle components. Neuron 2021; 109:1675-1691.e9. [PMID: 33848474 PMCID: PMC8141031 DOI: 10.1016/j.neuron.2021.03.026] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 02/05/2021] [Accepted: 03/18/2021] [Indexed: 12/13/2022]
Abstract
Tau aggregates contribute to neurodegenerative diseases, including frontotemporal dementia and Alzheimer's disease (AD). Although RNA promotes tau aggregation in vitro, whether tau aggregates in cells contain RNA is unknown. We demonstrate, in cell culture and mouse brains, that cytosolic and nuclear tau aggregates contain RNA with enrichment for small nuclear RNAs (snRNAs) and small nucleolar RNAs (snoRNAs). Nuclear tau aggregates colocalize with and alter the composition, dynamics, and organization of nuclear speckles, membraneless organelles involved in pre-mRNA splicing. Moreover, several nuclear speckle components, including SRRM2, mislocalize to cytosolic tau aggregates in cells, mouse brains, and brains of individuals with AD, frontotemporal dementia (FTD), and corticobasal degeneration (CBD). Consistent with these alterations, we observe that the presence of tau aggregates is sufficient to alter pre-mRNA splicing. This work identifies tau alteration of nuclear speckles as a feature of tau aggregation that may contribute to the pathology of tau aggregates.
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Affiliation(s)
- Evan Lester
- Department of Biochemistry, University of Colorado, Boulder, CO, USA; Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Felicia K Ooi
- Institute for Neurodegenerative Diseases, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Nadine Bakkar
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, AZ, USA
| | - Jacob Ayers
- Institute for Neurodegenerative Diseases, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA; Department of Neurology, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Amanda L Woerman
- Department of Biology and Institute for Applied Life Sciences, University of Massachusetts Amherst, Amherst, MA, USA
| | - Joshua Wheeler
- Department of Biochemistry, University of Colorado, Boulder, CO, USA; Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Department of Pathology, Stanford University, Stanford, CA, USA
| | - Robert Bowser
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, AZ, USA
| | - George A Carlson
- Institute for Neurodegenerative Diseases, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA; Department of Neurology, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Stanley B Prusiner
- Institute for Neurodegenerative Diseases, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA; Department of Neurology, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA; Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Roy Parker
- Department of Biochemistry, University of Colorado, Boulder, CO, USA; Howard Hughes Medical Institute, University of Colorado, Boulder, CO, USA.
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11
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Ilik İA, Malszycki M, Lübke AK, Schade C, Meierhofer D, Aktaş T. SON and SRRM2 are essential for nuclear speckle formation. eLife 2020; 9:60579. [PMID: 33095160 PMCID: PMC7671692 DOI: 10.7554/elife.60579] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/20/2020] [Indexed: 12/17/2022] Open
Abstract
Nuclear speckles (NS) are among the most prominent biomolecular condensates. Despite their prevalence, research on the function of NS is virtually restricted to colocalization analyses, since an organizing core, without which NS cannot form, remains unidentified. The monoclonal antibody SC35, raised against a spliceosomal extract, is frequently used to mark NS. Unexpectedly, we found that this antibody was mischaracterized and the main target of SC35 mAb is SRRM2, a spliceosome-associated protein that sharply localizes to NS. Here we show that, the core of NS is likely formed by SON and SRRM2, since depletion of SON leads only to a partial disassembly of NS, while co-depletion of SON and SRRM2 or depletion of SON in a cell-line where intrinsically disordered regions (IDRs) of SRRM2 are genetically deleted, leads to a near-complete dissolution of NS. This work, therefore, paves the way to study the role of NS under diverse physiological and stress conditions. Most cells store their genetic material inside a compartment called the nucleus, which helps to separate DNA from other molecules in the cell. Inside the nucleus, DNA is tightly packed together with proteins that can read the cell’s genetic code and convert into the RNA molecules needed to build proteins. However, the contents of the nucleus are not randomly arranged, and these proteins are often clustered into specialized areas where they perform their designated roles. One of the first nuclear territories to be identified were granular looking structures named Nuclear Speckles (or NS for short), which are thought to help process RNA before it leaves the nucleus. Structures like NS often contain a number of different factors held together by a core group of proteins known as a scaffold. Although NS were discovered over a century ago, little is known about their scaffold proteins, making it difficult to understand the precise role of these speckles. Typically, researchers visualize NS using a substance called SC35 which targets specific sites in these structures. However, it was unclear which parts of the NS this marker binds to. To answer this question, Ilik et al. studied NS in human cells grown in the lab. The analysis revealed that SC35 attaches to certain parts of a large, flexible protein called SRRM2. Ilik et al. discovered that although the structure and sequence of SRMM2 varies between different animal species, a small region of this protein remained unchanged throughout evolution. Studying the evolutionary history of SRRM2 led to the identification of another protein with similar properties called SON. Ilik et al. found that depleting SON and SRRM2 from human cells caused other proteins associated with the NS to diffuse away from their territories and become dispersed within the nucleus. This suggests that SRMM2 and SON make up the scaffold that holds the proteins in NS together. Nuclear speckles have been associated with certain viral infections, and seem to help prevent the onset of diseases such as Huntington’s and spinocerebellar ataxia. These newly discovered core proteins could therefore further our understanding of the role NS play in disease.
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Affiliation(s)
| | - Michal Malszycki
- Max Planck Institute for Molecular Genetics, Berlin, Germany.,Freie Universität Berlin, Berlin, Germany
| | - Anna Katharina Lübke
- Max Planck Institute for Molecular Genetics, Berlin, Germany.,Freie Universität Berlin, Berlin, Germany
| | - Claudia Schade
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | | | - Tuğçe Aktaş
- Max Planck Institute for Molecular Genetics, Berlin, Germany
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12
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Jia J, Ganichkin OM, Preußner M, Absmeier E, Alings C, Loll B, Heyd F, Wahl MC. A Snu114-GTP-Prp8 module forms a relay station for efficient splicing in yeast. Nucleic Acids Res 2020; 48:4572-4584. [PMID: 32196113 PMCID: PMC7192624 DOI: 10.1093/nar/gkaa182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/26/2020] [Accepted: 03/10/2020] [Indexed: 01/24/2023] Open
Abstract
The single G protein of the spliceosome, Snu114, has been proposed to facilitate splicing as a molecular motor or as a regulatory G protein. However, available structures of spliceosomal complexes show Snu114 in the same GTP-bound state, and presently no Snu114 GTPase-regulatory protein is known. We determined a crystal structure of Snu114 with a Snu114-binding region of the Prp8 protein, in which Snu114 again adopts the same GTP-bound conformation seen in spliceosomes. Snu114 and the Snu114–Prp8 complex co-purified with endogenous GTP. Snu114 exhibited weak, intrinsic GTPase activity that was abolished by the Prp8 Snu114-binding region. Exchange of GTP-contacting residues in Snu114, or of Prp8 residues lining the Snu114 GTP-binding pocket, led to temperature-sensitive yeast growth and affected the same set of splicing events in vivo. Consistent with dynamic Snu114-mediated protein interactions during splicing, our results suggest that the Snu114–GTP–Prp8 module serves as a relay station during spliceosome activation and disassembly, but that GTPase activity may be dispensable for splicing.
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Affiliation(s)
- Junqiao Jia
- Freie Universität Berlin, Laboratory of Structural Biochemistry, Takustraβe 6, D-14195 Berlin, Germany
| | - Oleg M Ganichkin
- Freie Universität Berlin, Laboratory of Structural Biochemistry, Takustraβe 6, D-14195 Berlin, Germany
| | - Marco Preußner
- Freie Universität Berlin, Laboratory of RNA Biochemistry, Takustraβe 6, D-14195 Berlin, Germany
| | - Eva Absmeier
- Freie Universität Berlin, Laboratory of Structural Biochemistry, Takustraβe 6, D-14195 Berlin, Germany
| | - Claudia Alings
- Freie Universität Berlin, Laboratory of Structural Biochemistry, Takustraβe 6, D-14195 Berlin, Germany
| | - Bernhard Loll
- Freie Universität Berlin, Laboratory of Structural Biochemistry, Takustraβe 6, D-14195 Berlin, Germany
| | - Florian Heyd
- Freie Universität Berlin, Laboratory of RNA Biochemistry, Takustraβe 6, D-14195 Berlin, Germany
| | - Markus C Wahl
- Freie Universität Berlin, Laboratory of Structural Biochemistry, Takustraβe 6, D-14195 Berlin, Germany.,Helmholtz-Zentrum Berlin für Materialien und Energie, Macromolecular Crystallography, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
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13
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Barbosa RL, da Cunha JPC, Menezes AT, Melo RDFP, Elias MC, Silber AM, Coltri PP. Proteomic analysis of Trypanosoma cruzi spliceosome complex. J Proteomics 2020; 223:103822. [PMID: 32422275 DOI: 10.1016/j.jprot.2020.103822] [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: 11/29/2019] [Revised: 05/01/2020] [Accepted: 05/11/2020] [Indexed: 11/17/2022]
Abstract
The unicellular protists of the group Kinetoplastida include the genera Leishmania and Trypanosoma, which are pathogens of invertebrate and vertebrate animals. Despite their medical and economical importance, critical aspects of their biology such as specific molecular characteristics of gene expression regulation are just beginning to be deciphered. Gene expression regulation also depends on post-transcriptional processing steps, such as the trans-splicing process. Despite being widely used in trypanosomes, trans-splicing is a rare event in other eukaryotes. We sought to describe the protein composition of spliceosomes in epimastigotes of T. cruzi, the etiological agent of Chagas disease. We used two TAP-tagged proteins to affinity purify spliceosomes and analyzed their composition by mass spectrometry. Among the 115 identified proteins we detected conserved spliceosome components, as Sm and LSm proteins, RNA helicases, U2- and U5-snRNP specific proteins. Importantly, by comparing our data with proteomic data of human and T. brucei spliceosome complexes, we observed a core group of proteins common to all spliceosomes. By using amino acid sequence comparisons, we identified RNA-associated proteins that might be involved with splicing regulation in T. cruzi, namely the orthologous of WDR33, PABPCL1 and three different HNRNPs. Data are available via ProteomeXchange with identifier PXD018776.
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Affiliation(s)
- Rosicler L Barbosa
- Department of Cell and Developmental Biology, Institute for Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - Julia Pinheiro Chagas da Cunha
- Special Laboratory of Cell Cycle, Center of Toxins, Immune Response and Cell Signalling (CeTICS), Butantan Institute, São Paulo 05503-900, Brazil
| | - Arthur T Menezes
- Department of Cell and Developmental Biology, Institute for Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - Raíssa de F P Melo
- Laboratory of Biochemistry of Tryps - LaBTryps. Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - Maria Carolina Elias
- Special Laboratory of Cell Cycle, Center of Toxins, Immune Response and Cell Signalling (CeTICS), Butantan Institute, São Paulo 05503-900, Brazil
| | - Ariel M Silber
- Laboratory of Biochemistry of Tryps - LaBTryps. Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - Patricia P Coltri
- Department of Cell and Developmental Biology, Institute for Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil.
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14
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Tian Y, Wen H, Qi X, Zhang X, Sun Y, Li J, He F, Zhang M, Zhang K, Yang W, Huang Z, Ren Y, Li Y. Alternative splicing (AS) mechanism plays important roles in response to different salinity environments in spotted sea bass. Int J Biol Macromol 2020; 155:50-60. [DOI: 10.1016/j.ijbiomac.2020.03.178] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 01/12/2023]
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15
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Abstract
Splicing of the precursor messenger RNA, involving intron removal and exon ligation, is mediated by the spliceosome. Together with biochemical and genetic investigations of the past four decades, structural studies of the intact spliceosome at atomic resolution since 2015 have led to mechanistic delineation of RNA splicing with remarkable insights. The spliceosome is proven to be a protein-orchestrated metalloribozyme. Conserved elements of small nuclear RNA (snRNA) constitute the splicing active site with two catalytic metal ions and recognize three conserved intron elements through duplex formation, which are delivered into the splicing active site for branching and exon ligation. The protein components of the spliceosome stabilize the conformation of the snRNA, drive spliceosome remodeling, orchestrate the movement of the RNA elements, and facilitate the splicing reaction. The overall organization of the spliceosome and the configuration of the splicing active site are strictly conserved between human and yeast.
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Affiliation(s)
- Ruixue Wan
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China;,
| | - Rui Bai
- Institute of Biology, Westlake Institute for Advanced Study, Westlake University, Hangzhou 310024, China
| | - Xiechao Zhan
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China;,
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China;,
- Institute of Biology, Westlake Institute for Advanced Study, Westlake University, Hangzhou 310024, China
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16
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Zhao X, Xiao T, Jin S, Wang J, Wang J, Luo H, Li R, Sun T, Zou J, Li Y. Characterization and immune function of the interferon-β promoter stimulator-1 in the barbel chub, Squaliobarbus curriculus. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 104:103571. [PMID: 31837379 DOI: 10.1016/j.dci.2019.103571] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/29/2019] [Accepted: 12/10/2019] [Indexed: 06/10/2023]
Abstract
To elucidate the immunity-protecting role of the interferon-β promoter stimulator-1 (ScIPS-1) in barbel chub Squaliobarbus curriculus, the full-length cDNA of ScIPS-1 was cloned and expression levels in response to stimulation were investigated. In addition, the function of ScIPS-1 and its domains were analyzed. The full-length cDNA of ScIPS-1 is 2524 bp and encodes 601 aa. The N-terminal caspase activation and recruitment domain, central proline-rich domain, C-terminal transmembrane domain, C2HC-zinc finger, and Cwf21 domains were identified. The mRNA level of ScIPS-1 was the highest in the kidney, whereas the highest protein level was observed in the liver. The ScIPS-1 expressions were significantly up-regulated after lipopolysaccharide and poly I:C treatment. The ScIPS-1 protein level was up-regulated at 12 h in the head kidney and was up-regulated at 12 h and then down-regulated from 12 to 48 h in the liver after grass carp reovirus (GCRV) infection. The CiIFN and CiMx transcription levels were significantly enhanced in pEGFP-C1-IPS-1 and pcDNA3.1-ΔCwf21 overexpressing cells after GCRV infection. The results indicate that ScIPS-1 may function in the immune response against pathogens and provide a basis for achieving resistance to diseases in fish breeding.
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Affiliation(s)
- Xin Zhao
- Hunan Engineering Technology Research Center of Featured Aquatic Resources Utilization, Hunan Agricultural University, Changsha, 410128, China
| | - Tiaoyi Xiao
- Hunan Engineering Technology Research Center of Featured Aquatic Resources Utilization, Hunan Agricultural University, Changsha, 410128, China
| | - Shengzhen Jin
- Hunan Engineering Technology Research Center of Featured Aquatic Resources Utilization, Hunan Agricultural University, Changsha, 410128, China
| | - Jing'an Wang
- Hunan Engineering Technology Research Center of Featured Aquatic Resources Utilization, Hunan Agricultural University, Changsha, 410128, China
| | - Junya Wang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Hong Luo
- Hunan Engineering Technology Research Center of Featured Aquatic Resources Utilization, Hunan Agricultural University, Changsha, 410128, China
| | - Rui Li
- Hunan Engineering Technology Research Center of Featured Aquatic Resources Utilization, Hunan Agricultural University, Changsha, 410128, China
| | - Tong Sun
- Hunan Engineering Technology Research Center of Featured Aquatic Resources Utilization, Hunan Agricultural University, Changsha, 410128, China
| | - Jun Zou
- Hunan Engineering Technology Research Center of Featured Aquatic Resources Utilization, Hunan Agricultural University, Changsha, 410128, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Yaoguo Li
- Hunan Engineering Technology Research Center of Featured Aquatic Resources Utilization, Hunan Agricultural University, Changsha, 410128, China.
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17
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Ustaoglu P, Haussmann IU, Liao H, Torres-Mendez A, Arnold R, Irimia M, Soller M. Srrm234, but not canonical SR and hnRNP proteins, drive inclusion of Dscam exon 9 variable exons. RNA (NEW YORK, N.Y.) 2019; 25:1353-1365. [PMID: 31292260 PMCID: PMC6800468 DOI: 10.1261/rna.071316.119] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/04/2019] [Indexed: 05/24/2023]
Abstract
Alternative splicing of pre-mRNA is a major mechanism to diversify protein functionality in metazoans from a limited number of genes. The Drosophila melanogaster Down syndrome cell adhesion molecule (Dscam) gene, which is important for neuronal wiring and phagocytosis of bacteria, can generate up to 38,016 isoforms by mutually exclusive alternative splicing in four clusters of variable exons. However, it is not understood how a specific exon is chosen from the many variables and how variable exons are prevented from being spliced together. A main role in the regulation of Dscam alternative splicing has been attributed to RNA binding proteins (RBPs), but how they impact on exon selection is not well understood. Serine-arginine rich (SR) proteins and hnRNP proteins are the two main types of RBPs with major roles in exon definition and splice site selection. Here, we analyzed the role of SR and hnRNP proteins in Dscam exon 9 alternative splicing in mutant Drosophila melanogaster embryos because of their essential function for development. Strikingly, loss or overexpression of canonical SR and hnRNP proteins even when multiple proteins are depleted together, does not affect Dscam alternative exon selection very dramatically. Conversely, noncanonical SR protein Serine-arginine repetitive matrix 2/3/4 (Srrm234) is a main determinant of exon inclusion in the Dscam exon 9 cluster. Since long-range base-pairings are absent in the exon 9 cluster, our data argue for a small complement of regulatory factors as main determinants of exon inclusion in the Dscam exon 9 cluster.
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Affiliation(s)
- Pinar Ustaoglu
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Irmgard U Haussmann
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
- Department of Life Science, School of Health Sciences, Birmingham City University, Birmingham B5 3TN, United Kingdom
| | - Hongzhi Liao
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Antonio Torres-Mendez
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
| | - Roland Arnold
- Institute of Cancer and Genomics Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Manuel Irimia
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain
- ICREA, Barcelona 08010, Spain
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
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18
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A novel protein domain in an ancestral splicing factor drove the evolution of neural microexons. Nat Ecol Evol 2019; 3:691-701. [DOI: 10.1038/s41559-019-0813-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 01/16/2019] [Indexed: 02/02/2023]
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19
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Gautam A, Beggs JD. Mutagenesis of Snu114 domain IV identifies a developmental role in meiotic splicing. RNA Biol 2019; 16:185-195. [PMID: 30672374 PMCID: PMC6380292 DOI: 10.1080/15476286.2018.1561145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 12/03/2018] [Accepted: 12/16/2018] [Indexed: 11/23/2022] Open
Abstract
Snu114, a component of the U5 snRNP, plays a key role in activation of the spliceosome. It controls the action of Brr2, an RNA-stimulated ATPase/RNA helicase that disrupts U4/U6 snRNA base-pairing prior to formation of the spliceosome's catalytic centre. Snu114 has a highly conserved domain structure that resembles that of the GTPase EF-2/EF-G in the ribosome. It has been suggested that the regulatory function of Snu114 in activation of the spliceosome is mediated by its C-terminal region, however, there has been only limited characterisation of the interactions of the C-terminal domains. We show a direct interaction between protein phosphatase PP1 and Snu114 domain 'IVa' and identify sequence 'YGVQYK' as a PP1 binding motif. Interestingly, this motif is also required for Cwc21 binding. We provide evidence for mutually exclusive interaction of Cwc21 and PP1 with Snu114 and show that the affinity of Cwc21 and PP1 for Snu114 is influenced by the different nucleotide-bound states of Snu114. Moreover, we identify a novel mutation in domain IVa that, while not affecting vegetative growth of yeast cells, causes a defect in splicing transcripts of the meiotic genes, SPO22, AMA1 and MER2, thereby inhibiting an early stage of meiosis.
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Affiliation(s)
- Amit Gautam
- a Wellcome Centre for Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Jean D Beggs
- a Wellcome Centre for Cell Biology , University of Edinburgh , Edinburgh , UK
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20
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Mechanistic insights into precursor messenger RNA splicing by the spliceosome. Nat Rev Mol Cell Biol 2017; 18:655-670. [DOI: 10.1038/nrm.2017.86] [Citation(s) in RCA: 234] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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21
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Shi Y. The Spliceosome: A Protein-Directed Metalloribozyme. J Mol Biol 2017; 429:2640-2653. [PMID: 28733144 DOI: 10.1016/j.jmb.2017.07.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 11/15/2022]
Abstract
Pre-mRNA splicing is executed by the ribonucleoprotein machinery spliceosome. Nearly 40 years after the discovery of pre-mRNA splicing, the atomic structure of the spliceosome has finally come to light. Four distinct conformational states of the yeast spliceosome have been captured at atomic or near-atomic resolutions. Two catalytic metal ions at the active site are specifically coordinated by the U6 small nuclear RNA (snRNA) and catalyze both the branching reaction and the exon ligation. Of the three snRNAs in the fully assembled spliceosome, U5 and U6, along with 30 contiguous nucleotides of U2 at its 5'-end, remain structurally rigid throughout the splicing reaction. The rigidity of these RNA elements is safeguarded by Prp8 and 16 core protein components, which maintain the same overall conformation in all structurally characterized spliceosomes during the splicing reaction. Only the sequences downstream of nucleotide 30 of U2 snRNA are mobile; their movement, directed by the protein components, delivers the intron branch site into the close proximity of the 5'-splice site for the branching reaction. A set of additional structural rearrangement is required for exon ligation, and the lariat junction is moved out of the active site for recruitment of the 3'-splice site and 3'-exon. The spliceosome is proven to be a protein-directed metalloribozyme.
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Affiliation(s)
- Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Xihu District, Hangzhou 310064, Zhejiang Province, Province, China.
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22
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Yu Q, Shi X, Feng Y, Kent KC, Li L. Improving data quality and preserving HCD-generated reporter ions with EThcD for isobaric tag-based quantitative proteomics and proteome-wide PTM studies. Anal Chim Acta 2017; 968:40-49. [PMID: 28395773 PMCID: PMC5509462 DOI: 10.1016/j.aca.2017.03.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 02/03/2017] [Accepted: 03/02/2017] [Indexed: 11/22/2022]
Abstract
Mass spectrometry (MS)-based isobaric labeling has undergone rapid development in recent years due to its capability for high throughput quantitation. Apart from its originally designed use with collision-induced dissociation (CID) and higher-energy collisional dissociation (HCD), isobaric tagging technique could also work with electron-transfer dissociation (ETD), which provides complementarity to CID and is preferred in sequencing peptides with post-translational modifications (PTMs). However, ETD suffers from long reaction time, reduced duty cycle and bias against peptides with lower charge states. In addition, common fragmentation mechanism in ETD results in altered reporter ion production, decreased multiplexing capability, and even loss of quantitation capability for some of the isobaric tags, including custom-designed dimethyl leucine (DiLeu) tags. Here, we demonstrate a novel electron-transfer/higher-energy collision dissociation (EThcD) approach that preserves original reporter ion channels, mitigates bias against lower charge states, improves sensitivity, and significantly improves data quality for quantitative proteomics and proteome-wide PTM studies. Systematic optimization was performed to achieve a balance between data quality and sensitivity. We provide direct comparison of EThcD with ETD and HCD for DiLeu- and TMT-labeled HEK cell lysate and IMAC enriched phosphopeptides. Results demonstrate improved data quality and phosphorylation localization accuracy while preserving sufficient reporter ion production. Biological studies were performed to investigate phosphorylation changes in a mouse vascular smooth muscle cell line treated with four different conditions. Overall, EThcD exhibits superior performance compared to conventional ETD and offers distinct advantages compared to HCD in isobaric labeling based quantitative proteomics and quantitative PTM studies.
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Affiliation(s)
- Qing Yu
- School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
| | - Xudong Shi
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705, USA
| | - Yu Feng
- School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
| | - K Craig Kent
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705, USA
| | - Lingjun Li
- School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA; Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA.
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23
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Mayerle M, Guthrie C. Genetics and biochemistry remain essential in the structural era of the spliceosome. Methods 2017; 125:3-9. [PMID: 28132896 DOI: 10.1016/j.ymeth.2017.01.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 01/23/2017] [Indexed: 12/31/2022] Open
Abstract
The spliceosome is not a single macromolecular machine. Rather it is a collection of dynamic heterogeneous subcomplexes that rapidly interconvert throughout the course of a typical splicing cycle. Because of this, for many years the only high resolution structures of the spliceosome available were of smaller, isolated protein or RNA components. Consequently much of our current understanding of the spliceosome derives from biochemical and genetic techniques. Now with the publication of multiple, high resolution structures of the spliceosome, some question the relevance of traditional biochemical and genetic techniques to the splicing field. We argue such techniques are not only relevant, but vital for an in depth mechanistic understanding of pre-mRNA splicing.
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Affiliation(s)
- Megan Mayerle
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94143, USA
| | - Christine Guthrie
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94143, USA.
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24
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Sun C, Rigo N, Fabrizio P, Kastner B, Lührmann R. A protein map of the yeast activated spliceosome as obtained by electron microscopy. RNA (NEW YORK, N.Y.) 2016; 22:1427-40. [PMID: 27368340 PMCID: PMC4986897 DOI: 10.1261/rna.057778.116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 05/31/2016] [Indexed: 05/09/2023]
Abstract
We have elucidated the spatial arrangement of proteins and snRNP subunits within the purified spliceosomal B(act) complex from Saccharomyces cerevisiae, using negative-stain immunoelectron microscopy. The B(act) spliceosome exhibits a mushroom-like shape with a main body connected to a foot and a steep and a shallow slope. The U5 core components, including proteins Snu114 and Prp8, are located in the main body and foot, while Brr2 is on the shallow slope. U2 snRNP components and the RNA helicase Prp2 were predominantly located in the upper regions of both slopes. While several proteins of the "nineteen complex" are located on the steep slope, Prp19, Cef1, and the U6 snRNA-binding protein Cwc2 are on the main body. Our results also indicate that the catalytic core RNP of the spliceosome resides in its main body. We thus assign distinct domains of the B(act) complex to its snRNP and protein components, and we provide first structural insights into the remodeling events at the spliceosome during its transformation from the B to the B(act) complex.
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Affiliation(s)
- Chengfu Sun
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Norbert Rigo
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Patrizia Fabrizio
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Berthold Kastner
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Reinhard Lührmann
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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25
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Cryo-EM structure of the spliceosome immediately after branching. Nature 2016; 537:197-201. [PMID: 27459055 PMCID: PMC5156311 DOI: 10.1038/nature19316] [Citation(s) in RCA: 177] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 07/19/2016] [Indexed: 12/11/2022]
Abstract
Precursor mRNA (pre-mRNA) splicing proceeds by two consecutive transesterification reactions via a lariat-intron intermediate. Here we present the 3.8 Å cryo-electron microscopy structure of the spliceosome immediately after lariat formation. The 5'-splice site is cleaved but remains close to the catalytic Mg2+ site in the U2/U6 small nuclear RNA (snRNA) triplex, and the 5'-phosphate of the intron nucleotide G(+1) is linked to the branch adenosine 2'OH. The 5'-exon is held between the Prp8 amino-terminal and linker domains, and base-pairs with U5 snRNA loop 1. Non-Watson-Crick interactions between the branch helix and 5'-splice site dock the branch adenosine into the active site, while intron nucleotides +3 to +6 base-pair with the U6 snRNA ACAGAGA sequence. Isy1 and the step-one factors Yju2 and Cwc25 stabilize docking of the branch helix. The intron downstream of the branch site emerges between the Prp8 reverse transcriptase and linker domains and extends towards the Prp16 helicase, suggesting a plausible mechanism of remodelling before exon ligation.
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26
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Yan C, Wan R, Bai R, Huang G, Shi Y. Structure of a yeast activated spliceosome at 3.5 Å resolution. Science 2016; 353:904-11. [PMID: 27445306 DOI: 10.1126/science.aag0291] [Citation(s) in RCA: 200] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/13/2016] [Indexed: 12/18/2022]
Abstract
Pre-messenger RNA (pre-mRNA) splicing is carried out by the spliceosome, which undergoes an intricate assembly and activation process. Here, we report an atomic structure of an activated spliceosome (known as the B(act) complex) from Saccharomyces cerevisiae, determined by cryo-electron microscopy at an average resolution of 3.52 angstroms. The final refined model contains U2 and U5 small nuclear ribonucleoprotein particles (snRNPs), U6 small nuclear RNA (snRNA), nineteen complex (NTC), NTC-related (NTR) protein, and a 71-nucleotide pre-mRNA molecule, which amount to 13,505 amino acids from 38 proteins and a combined molecular mass of about 1.6 megadaltons. The 5' exon is anchored by loop I of U5 snRNA, whereas the 5' splice site (5'SS) and the branch-point sequence (BPS) of the intron are specifically recognized by U6 and U2 snRNA, respectively. Except for coordination of the catalytic metal ions, the RNA elements at the catalytic cavity of Prp8 are mostly primed for catalysis. The catalytic latency is maintained by the SF3b complex, which encircles the BPS, and the splicing factors Cwc24 and Prp11, which shield the 5' exon-5'SS junction. This structure, together with those determined earlier, outlines a molecular framework for the pre-mRNA splicing reaction.
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Affiliation(s)
- Chuangye Yan
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ruixue Wan
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Rui Bai
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Gaoxingyu Huang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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27
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Wan R, Yan C, Bai R, Huang G, Shi Y. Structure of a yeast catalytic step I spliceosome at 3.4 Å resolution. Science 2016; 353:895-904. [PMID: 27445308 DOI: 10.1126/science.aag2235] [Citation(s) in RCA: 162] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 07/14/2016] [Indexed: 12/30/2022]
Abstract
Each cycle of pre-messenger RNA splicing, carried out by the spliceosome, comprises two sequential transesterification reactions, which result in the removal of an intron and the joining of two exons. Here we report an atomic structure of a catalytic step I spliceosome (known as the C complex) from Saccharomyces cerevisiae, as determined by cryo-electron microscopy at an average resolution of 3.4 angstroms. In the structure, the 2'-OH of the invariant adenine nucleotide in the branch point sequence (BPS) is covalently joined to the phosphate at the 5' end of the 5' splice site (5'SS), forming an intron lariat. The freed 5' exon remains anchored to loop I of U5 small nuclear RNA (snRNA), and the 5'SS and BPS of the intron form duplexes with conserved U6 and U2 snRNA sequences, respectively. Specific placement of these RNA elements at the catalytic cavity of Prp8 is stabilized by 15 protein components, including Snu114 and the splicing factors Cwc21, Cwc22, Cwc25, and Yju2. These features, representing the conformation of the spliceosome after the first-step reaction, predict structural changes that are needed for the execution of the second-step transesterification reaction.
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Affiliation(s)
- Ruixue Wan
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Chuangye Yan
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Rui Bai
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Gaoxingyu Huang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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28
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CryoEM structures of two spliceosomal complexes: starter and dessert at the spliceosome feast. Curr Opin Struct Biol 2016; 36:48-57. [PMID: 26803803 PMCID: PMC4830896 DOI: 10.1016/j.sbi.2015.12.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 12/21/2015] [Indexed: 12/31/2022]
Abstract
Recent advances in cryoEM are revolutionizing our understanding of how molecular machines function. The structure of Saccharomyces cerevisiae U4/U6.U5 tri-snRNP has been revealed. The structure of Schizosaccharomyces pombe U2.U6.U5 spliceosomal complex has been revealed. These structures greatly advanced our understanding of the mechanism of pre-mRNA splicing.
The spliceosome is formed on pre-mRNA substrates from five small nuclear ribonucleoprotein particles (U1, U2, U4/U6 and U5 snRNPs), and numerous non-snRNP factors. Saccharomyces cerevisiae U4/U6.U5 tri-snRNP comprises U5 snRNA, U4/U6 snRNA duplex and approximately 30 proteins and represents a substantial part of the spliceosome before activation. Schizosaccharomyces pombe U2.U6.U5 spliceosomal complex is a post-catalytic intron lariat spliceosome containing U2 and U5 snRNPs, NTC (nineteen complex), NTC-related proteins (NTR), U6 snRNA, and an RNA intron lariat. Two recent papers describe near-complete atomic structures of these complexes based on cryoEM single-particle analysis. The U4/U6.U5 tri-snRNP structure provides crucial insight into the activation mechanism of the spliceosome. The U2.U6.U5 complex reveals the striking architecture of NTC and NTR and important features of the group II intron-like catalytic RNA core remaining after spliced mRNA is released. These two structures greatly advance our understanding of the mechanism of pre-mRNA splicing.
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29
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Nguyen THD, Galej WP, Bai XC, Savva CG, Newman AJ, Scheres SHW, Nagai K. The architecture of the spliceosomal U4/U6.U5 tri-snRNP. Nature 2015; 523:47-52. [PMID: 26106855 PMCID: PMC4536768 DOI: 10.1038/nature14548] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 05/06/2015] [Indexed: 12/12/2022]
Abstract
U4/U6.U5 tri-snRNP is a 1.5-megadalton pre-assembled spliceosomal complex comprising U5 small nuclear RNA (snRNA), extensively base-paired U4/U6 snRNAs and more than 30 proteins, including the key components Prp8, Brr2 and Snu114. The tri-snRNP combines with a precursor messenger RNA substrate bound to U1 and U2 small nuclear ribonucleoprotein particles (snRNPs), and transforms into a catalytically active spliceosome after extensive compositional and conformational changes triggered by unwinding of the U4 and U6 (U4/U6) snRNAs. Here we use cryo-electron microscopy single-particle reconstruction of Saccharomyces cerevisiae tri-snRNP at 5.9 Å resolution to reveal the essentially complete organization of its RNA and protein components. The single-stranded region of U4 snRNA between its 3' stem-loop and the U4/U6 snRNA stem I is loaded into the Brr2 helicase active site ready for unwinding. Snu114 and the amino-terminal domain of Prp8 position U5 snRNA to insert its loop I, which aligns the exons for splicing, into the Prp8 active site cavity. The structure provides crucial insights into the activation process and the active site of the spliceosome.
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Affiliation(s)
| | - Wojciech P Galej
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Xiao-chen Bai
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Christos G Savva
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Andrew J Newman
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Sjors H W Scheres
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Kiyoshi Nagai
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
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30
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Lee NS, Evgrafov OV, Souaiaia T, Bonyad A, Herstein J, Lee JY, Kim J, Ning Y, Sixto M, Weitz AC, Lenz HJ, Wang K, Knowles JA, Press MF, Salvaterra PM, Shung KK, Chow RH. Non-coding RNAs derived from an alternatively spliced REST transcript (REST-003) regulate breast cancer invasiveness. Sci Rep 2015; 5:11207. [PMID: 26053433 PMCID: PMC4459148 DOI: 10.1038/srep11207] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/17/2015] [Indexed: 11/29/2022] Open
Abstract
RE1-Silencing Transcription factor (REST) has a well-established role in regulating transcription of genes important for neuronal development. Its role in cancer, though significant, is less well understood. We show that REST downregulation in weakly invasive MCF-7 breast cancer cells converts them to a more invasive phenotype, while REST overexpression in highly invasive MDA-MB-231 cells suppresses invasiveness. Surprisingly, the mechanism responsible for these phenotypic changes does not depend directly on the transcriptional function of REST protein. Instead, it is driven by previously unstudied mid-size (30–200 nt) non-coding RNAs (ncRNAs) derived from the first exon of an alternatively spliced REST transcript: REST-003. We show that processing of REST-003 into ncRNAs is controlled by an uncharacterized serine/arginine repeat-related protein, SRRM3. SRRM3 expression may be under REST-mediated transcriptional control, as it increases following REST downregulation. The SRRM3-dependent regulation of REST-003 processing into ncRNAs has many similarities to recently described promoter-associated small RNA-like processes. Targeting ncRNAs that control invasiveness could lead to new therapeutic approaches to limit breast cancer metastasis.
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Affiliation(s)
- Nan Sook Lee
- 1] Physiology &Biophysics and Zilkha Neurogenetic Institute, University of Southern California, Los Angeles [2] Dept of Biomedical Engineering, University of Southern California, Los Angeles
| | - Oleg V Evgrafov
- Psychiatry &the Behavioral Sciences, University of Southern California, Los Angeles
| | - Tade Souaiaia
- Psychiatry &the Behavioral Sciences, University of Southern California, Los Angeles
| | - Adrineh Bonyad
- Physiology &Biophysics and Zilkha Neurogenetic Institute, University of Southern California, Los Angeles
| | - Jennifer Herstein
- Psychiatry &the Behavioral Sciences, University of Southern California, Los Angeles
| | - Joo Yeun Lee
- Neuroscience Graduate Program, University of Southern California, Los Angeles
| | - Jihong Kim
- Psychiatry &the Behavioral Sciences, University of Southern California, Los Angeles
| | - Yan Ning
- Dept of Medicine, Norris Cancer Center, University of Southern California, Los Angeles
| | | | - Andrew C Weitz
- Dept of Ophthalmology, University of Southern California, Los Angeles, CA
| | - Heinz-Josef Lenz
- Dept of Medicine, Norris Cancer Center, University of Southern California, Los Angeles
| | - Kai Wang
- Psychiatry &the Behavioral Sciences, University of Southern California, Los Angeles
| | - James A Knowles
- Psychiatry &the Behavioral Sciences, University of Southern California, Los Angeles
| | - Michael F Press
- Dept of Pathology, Norris Cancer Center, University of Southern California, Los Angeles
| | - Paul M Salvaterra
- Department of Neuroscience, Beckman Research Institute of the City of Hope, Duarte, CA
| | - K Kirk Shung
- Dept of Biomedical Engineering, University of Southern California, Los Angeles
| | - Robert H Chow
- Physiology &Biophysics and Zilkha Neurogenetic Institute, University of Southern California, Los Angeles
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31
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Gautam A, Grainger RJ, Vilardell J, Barrass JD, Beggs JD. Cwc21p promotes the second step conformation of the spliceosome and modulates 3' splice site selection. Nucleic Acids Res 2015; 43:3309-17. [PMID: 25740649 PMCID: PMC4381068 DOI: 10.1093/nar/gkv159] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 02/18/2015] [Indexed: 12/20/2022] Open
Abstract
Pre-mRNA splicing involves two transesterification steps catalyzed by the spliceosome. How RNA substrates are positioned in each step and the molecular rearrangements involved, remain obscure. Here, we show that mutations in PRP16, PRP8, SNU114 and the U5 snRNA that affect this process interact genetically with CWC21, that encodes the yeast orthologue of the human SR protein, SRm300/SRRM2. Our microarray analysis shows changes in 3′ splice site selection at elevated temperature in a subset of introns in cwc21Δ cells. Considering all the available data, we propose a role for Cwc21p positioning the 3′ splice site at the transition to the second step conformation of the spliceosome, mediated through its interactions with the U5 snRNP. This suggests a mechanism whereby SRm300/SRRM2, might influence splice site selection in human cells.
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MESH Headings
- Adenosine Triphosphatases/chemistry
- Adenosine Triphosphatases/genetics
- Adenosine Triphosphatases/metabolism
- Alternative Splicing
- Amino Acid Sequence
- Carrier Proteins/chemistry
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Gene Deletion
- Genes, Fungal
- Humans
- Molecular Sequence Data
- Nucleic Acid Conformation
- Protein Conformation
- RNA Helicases/chemistry
- RNA Helicases/genetics
- RNA Helicases/metabolism
- RNA Precursors/chemistry
- RNA Precursors/genetics
- RNA Precursors/metabolism
- RNA Splice Sites
- RNA Splicing
- RNA Splicing Factors
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA-Binding Proteins/chemistry
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Ribonucleoprotein, U4-U6 Small Nuclear/chemistry
- Ribonucleoprotein, U4-U6 Small Nuclear/genetics
- Ribonucleoprotein, U4-U6 Small Nuclear/metabolism
- Ribonucleoprotein, U5 Small Nuclear/chemistry
- Ribonucleoprotein, U5 Small Nuclear/genetics
- Ribonucleoprotein, U5 Small Nuclear/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Saccharomyces cerevisiae Proteins/chemistry
- Saccharomyces cerevisiae Proteins/genetics
- Saccharomyces cerevisiae Proteins/metabolism
- Spliceosomes/chemistry
- Spliceosomes/genetics
- Spliceosomes/metabolism
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Affiliation(s)
- Amit Gautam
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3BF, UK
| | - Richard J Grainger
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3BF, UK
| | - J Vilardell
- Department of Molecular Genomics, Institute of Molecular Biology of Barcelona (IBMB), 08028 Barcelona, Spain Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - J David Barrass
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3BF, UK
| | - Jean D Beggs
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3BF, UK
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32
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Valadkhan S. The role of snRNAs in spliceosomal catalysis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 120:195-228. [PMID: 24156945 DOI: 10.1016/b978-0-12-381286-5.00006-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The spliceosomes, large ribonucleoprotein (RNP) assemblies that remove the intervening sequences from pre-mRNAs, contain a large number of proteins and five small nuclear RNAs (snRNAs). One snRNA, U6, contains highly conserved sequences that are thought to be the functional counterparts of the RNA elements that form the active site of self-splicing group II intron ribozymes. An in vitro-assembled, protein-free complex of U6 with U2, the base-pairing partner in the spliceosomal catalytic core, can catalyze a two-step splicing reaction in the absence of all other spliceosomal factors, suggesting that the two snRNAs may form all or a large share of the spliceosomal active site. On the other hand, several spliceosomal proteins are thought to help in the formation of functionally required RNA-RNA interactions in the catalytic core. Whether they also contribute functional groups to the spliceosomal active site, and thus whether the spliceosomes are RNA or RNP enzymes remain uncertain.
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Affiliation(s)
- Saba Valadkhan
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, USA
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33
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Chen W, Shulha HP, Ashar-Patel A, Yan J, Green KM, Query CC, Rhind N, Weng Z, Moore MJ. Endogenous U2·U5·U6 snRNA complexes in S. pombe are intron lariat spliceosomes. RNA (NEW YORK, N.Y.) 2014; 20:308-20. [PMID: 24442611 PMCID: PMC3923126 DOI: 10.1261/rna.040980.113] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Excision of introns from pre-mRNAs is mediated by the spliceosome, a multi-megadalton complex consisting of U1, U2, U4/U6, and U5 snRNPs plus scores of associated proteins. Spliceosome assembly and disassembly are highly dynamic processes involving multiple stable intermediates. In this study, we utilized a split TAP-tag approach for large-scale purification of an abundant endogenous U2·U5·U6 complex from Schizosaccharomyces pombe. RNAseq revealed this complex to largely contain excised introns, indicating that it is primarily ILS (intron lariat spliceosome) complexes. These endogenous ILS complexes are remarkably resistant to both high-salt and nuclease digestion. Mass spectrometry analysis identified 68, 45, and 43 proteins in low-salt-, high-salt-, and micrococcal nuclease-treated preps, respectively. The protein content of a S. pombe ILS complex strongly resembles that previously reported for human spliced product (P) and Saccharomyces cerevisiae ILS complexes assembled on single pre-mRNAs in vitro. However, the ATP-dependent RNA helicase Brr2 was either substoichiometric in low-salt preps or completely absent from high-salt and MNase preps. Because Brr2 facilitates spliceosome disassembly, its relative absence may explain why the ILS complex accumulates logarithmically growing cultures and the inability of S. pombe extracts to support in vitro splicing.
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Affiliation(s)
- Weijun Chen
- Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Hennady P. Shulha
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
- Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Ami Ashar-Patel
- Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Jing Yan
- Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Karin M. Green
- UMMS Proteomics and Mass Spectrometry Facility, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | | | - Nick Rhind
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Zhiping Weng
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
- Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Melissa J. Moore
- Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
- Corresponding authorE-mail
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Fontrodona L, Porta-de-la-Riva M, Morán T, Niu W, Díaz M, Aristizábal-Corrales D, Villanueva A, Schwartz S, Reinke V, Cerón J. RSR-2, the Caenorhabditis elegans ortholog of human spliceosomal component SRm300/SRRM2, regulates development by influencing the transcriptional machinery. PLoS Genet 2013; 9:e1003543. [PMID: 23754964 PMCID: PMC3675011 DOI: 10.1371/journal.pgen.1003543] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 04/20/2013] [Indexed: 02/04/2023] Open
Abstract
Protein components of the spliceosome are highly conserved in eukaryotes and can influence several steps of the gene expression process. RSR-2, the Caenorhabditis elegans ortholog of the human spliceosomal protein SRm300/SRRM2, is essential for viability, in contrast to the yeast ortholog Cwc21p. We took advantage of mutants and RNA interference (RNAi) to study rsr-2 functions in C. elegans, and through genetic epistasis analysis found that rsr-2 is within the germline sex determination pathway. Intriguingly, transcriptome analyses of rsr-2(RNAi) animals did not reveal appreciable splicing defects but instead a slight global decrease in transcript levels. We further investigated this effect in transcription and observed that RSR-2 colocalizes with DNA in germline nuclei and coprecipitates with chromatin, displaying a ChIP-Seq profile similar to that obtained for the RNA Polymerase II (RNAPII). Consistent with a novel transcription function we demonstrate that the recruitment of RSR-2 to chromatin is splicing-independent and that RSR-2 interacts with RNAPII and affects RNAPII phosphorylation states. Proteomic analyses identified proteins associated with RSR-2 that are involved in different gene expression steps, including RNA metabolism and transcription with PRP-8 and PRP-19 being the strongest interacting partners. PRP-8 is a core component of the spliceosome and PRP-19 is the core component of the PRP19 complex, which interacts with RNAPII and is necessary for full transcriptional activity. Taken together, our study proposes that RSR-2 is a multifunctional protein whose role in transcription influences C. elegans development.
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Affiliation(s)
- Laura Fontrodona
- Cancer and Human Molecular Genetics, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Montserrat Porta-de-la-Riva
- Cancer and Human Molecular Genetics, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
- C. elegans Core Facility, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Tomás Morán
- Cancer and Human Molecular Genetics, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
- Institute of Molecular Biology of Barcelona, IBMB - CSIC, Parc Científic de Barcelona, Barcelona, Spain
| | - Wei Niu
- Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Mònica Díaz
- Drug Delivery and Targeting, CIBBIM-Nanomedicine, Vall d'Hebron Research Institute, Universidad Autónoma de Barcelona, Barcelona, Spain
- Omnia Molecular, Parc Científic de Barcelona – UB, Barcelona, Spain
| | - David Aristizábal-Corrales
- Cancer and Human Molecular Genetics, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
- Drug Delivery and Targeting, CIBBIM-Nanomedicine, Vall d'Hebron Research Institute, Universidad Autónoma de Barcelona, Barcelona, Spain
| | - Alberto Villanueva
- Cancer and Human Molecular Genetics, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
- C. elegans Core Facility, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Simó Schwartz
- Drug Delivery and Targeting, CIBBIM-Nanomedicine, Vall d'Hebron Research Institute, Universidad Autónoma de Barcelona, Barcelona, Spain
- Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona, Spain
| | - Valerie Reinke
- Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Julián Cerón
- Cancer and Human Molecular Genetics, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
- C. elegans Core Facility, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
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Fourmann JB, Schmitzová J, Christian H, Urlaub H, Ficner R, Boon KL, Fabrizio P, Lührmann R. Dissection of the factor requirements for spliceosome disassembly and the elucidation of its dissociation products using a purified splicing system. Genes Dev 2013; 27:413-28. [PMID: 23431055 DOI: 10.1101/gad.207779.112] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The spliceosome is a single-turnover enzyme that needs to be dismantled after catalysis to both release the mRNA and recycle small nuclear ribonucleoproteins (snRNPs) for subsequent rounds of pre-mRNA splicing. The RNP remodeling events occurring during spliceosome disassembly are poorly understood, and the composition of the released snRNPs are only roughly known. Using purified components in vitro, we generated post-catalytic spliceosomes that can be dissociated into mRNA and the intron-lariat spliceosome (ILS) by addition of the RNA helicase Prp22 plus ATP and without requiring the step 2 proteins Slu7 and Prp18. Incubation of the isolated ILS with the RNA helicase Prp43 plus Ntr1/Ntr2 and ATP generates defined spliceosomal dissociation products: the intron-lariat, U6 snRNA, a 20-25S U2 snRNP containing SF3a/b, an 18S U5 snRNP, and the "nineteen complex" associated with both the released U2 snRNP and intron-lariat RNA. Our system reproduces the entire ordered disassembly phase of the spliceosome with purified components, which defines the minimum set of agents required for this process. It enabled us to characterize the proteins of the ILS by mass spectrometry and identify the ATPase action of Prp43 as necessary and sufficient for dissociation of the ILS without the involvement of Brr2 ATPase.
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Affiliation(s)
- Jean-Baptiste Fourmann
- Department of Cellular Biochemistry, Max-Planck-Institute of Biophysical Chemistry, D-37077 Göttingen, Germany
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Coelho Ribeiro MDL, Espinosa J, Islam S, Martinez O, Thanki JJ, Mazariegos S, Nguyen T, Larina M, Xue B, Uversky VN. Malleable ribonucleoprotein machine: protein intrinsic disorder in the Saccharomyces cerevisiae spliceosome. PeerJ 2013; 1:e2. [PMID: 23638354 PMCID: PMC3628832 DOI: 10.7717/peerj.2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 12/01/2012] [Indexed: 12/29/2022] Open
Abstract
Recent studies revealed that a significant fraction of any given proteome is presented by proteins that do not have unique 3D structures as a whole or in significant parts. These intrinsically disordered proteins possess dramatic structural and functional variability, being especially enriched in signaling and regulatory functions since their lack of fixed structure defines their ability to be involved in interaction with several proteins and allows them to be re-used in multiple pathways. Among recognized disorder-based protein functions are interactions with nucleic acids and multi-target binding; i.e., the functions ascribed to many spliceosomal proteins. Therefore, the spliceosome, a multimegadalton ribonucleoprotein machine catalyzing the excision of introns from eukaryotic pre-mRNAs, represents an attractive target for the focused analysis of the abundance and functionality of intrinsic disorder in its proteinaceous components. In yeast cells, spliceosome consists of five small nuclear RNAs (U1, U2, U4, U5, and U6) and a range of associated proteins. Some of these proteins constitute cores of the corresponding snRNA-protein complexes known as small nuclear ribonucleoproteins (snRNPs). Other spliceosomal proteins have various auxiliary functions. To gain better understanding of the functional roles of intrinsic disorder, we have studied the prevalence of intrinsically disordered proteins in the yeast spliceosome using a wide array of bioinformatics methods. Our study revealed that similar to the proteins associated with human spliceosomes (Korneta & Bujnicki, 2012), proteins found in the yeast spliceosome are enriched in intrinsic disorder.
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Affiliation(s)
- Maria de Lourdes Coelho Ribeiro
- Cancer Imaging Metabolism, H. Lee Moffitt Cancer Center & Research Institute , United States ; Department of Molecular Medicine, University of South Florida , Tampa, Florida , United States
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Abstract
In eukaryotic cells, introns are spliced from pre-mRNAs by the spliceosome. Both the composition and the structure of the spliceosome are highly dynamic, and eight DExD/H RNA helicases play essential roles in controlling conformational rearrangements. There is evidence that the various helicases are functionally and physically connected with each other and with many other factors in the spliceosome. Understanding the dynamics of those interactions is essential to comprehend the mechanism and regulation of normal as well as of pathological splicing. This review focuses on recent advances in the characterization of the splicing helicases and their interactions, and highlights the deep integration of splicing helicases in global mRNP biogenesis pathways.
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Affiliation(s)
- Olivier Cordin
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
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38
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Coltri PP, Oliveira CC. Cwc24p is a general Saccharomyces cerevisiae splicing factor required for the stable U2 snRNP binding to primary transcripts. PLoS One 2012; 7:e45678. [PMID: 23029180 PMCID: PMC3454408 DOI: 10.1371/journal.pone.0045678] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 08/23/2012] [Indexed: 12/31/2022] Open
Abstract
Splicing of primary transcripts is an essential process for the control of gene expression. Specific conserved sequences in premature transcripts are important to recruit the spliceosome machinery. The Saccharomyces cerevisiae catalytic spliceosome is composed of about 60 proteins and 5 snRNAs (U1, U2, U4/U6 and U5). Among these proteins, there are core components and regulatory factors, which might stabilize or facilitate splicing of specific substrates. Assembly of a catalytic complex depends on the dynamics of interactions between these proteins and RNAs. Cwc24p is an essential S. cerevisiae protein, originally identified as a component of the NTC complex, and later shown to affect splicing in vivo. In this work, we show that Cwc24p also affects splicing in vitro. We show that Cwc24p is important for the U2 snRNP binding to primary transcripts, co-migrates with spliceosomes, and that it interacts with Brr2p. Additionally, we show that Cwc24p is important for the stable binding of Prp19p to the spliceosome. We propose a model in which Cwc24p is required for stabilizing the U2 association with primary transcripts, and therefore, especially important for splicing of RNAs containing non-consensus branchpoint sequences.
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Affiliation(s)
- Patricia P. Coltri
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil
| | - Carla C. Oliveira
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil
- * E-mail:
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Silva MTAD, Ambrósio DL, Trevelin CC, Watanabe TF, Laure HJ, Greene LJ, Rosa JC, Valentini SR, Cicarelli RMB. New insights into trypanosomatid U5 small nuclear ribonucleoproteins. Mem Inst Oswaldo Cruz 2011; 106:130-8. [PMID: 21537670 DOI: 10.1590/s0074-02762011000200003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 12/01/2010] [Indexed: 11/22/2022] Open
Abstract
Several protozoan parasites exist in the Trypanosomatidae family, including various agents of human diseases. Multiple lines of evidence suggest that important differences are present between the translational and mRNA processing (trans splicing) systems of trypanosomatids and other eukaryotes. In this context, certain small complexes of RNA and protein, which are named small nuclear ribonucleoproteins (U snRNPs), have an essential role in pre-mRNA processing, mainly during splicing. Even though they are well defined in mammals, snRNPs are still not well characterized in trypanosomatids. This study shows that a U5-15K protein is highly conserved among various trypanosomatid species. Tandem affinity pull-down assays revealed that this protein interacts with a novel U5-102K protein, which suggests the presence of a sub-complex that is potentially involved in the assembly of U4/U6-U5 tri-snRNPs. Functional analyses showed that U5-15K is essential for cell viability and is somehow involved with the trans and cis splicing machinery. Similar tandem affinity experiments with a trypanonosomatid U5-Cwc21 protein led to the purification of four U5 snRNP specific proteins and a Sm core, suggesting U5-Cwc-21 participation in the 35S U5 snRNP particle. Of these proteins, U5-200K was molecularly characterized. U5-200K has conserved domains, such as the DEAD/DEAH box helicase and Sec63 domains and displays a strong interaction with U5 snRNA.
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Affiliation(s)
- Marco Túlio A da Silva
- Departamento de Ciências Biológicas, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
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40
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Lönnberg T. Understanding Catalysis of Phosphate‐Transfer Reactions by the Large Ribozymes. Chemistry 2011; 17:7140-53. [DOI: 10.1002/chem.201100009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Tuomas Lönnberg
- Department of Chemistry, University of Turku, Vatselankatu 2, 20140 Turku (Finland), Fax: (+358) 2‐333‐6700
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Dlakić M, Mushegian A. Prp8, the pivotal protein of the spliceosomal catalytic center, evolved from a retroelement-encoded reverse transcriptase. RNA (NEW YORK, N.Y.) 2011; 17:799-808. [PMID: 21441348 PMCID: PMC3078730 DOI: 10.1261/rna.2396011] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Prp8 is the largest and most highly conserved protein of the spliceosome, encoded by all sequenced eukaryotic genomes but missing from prokaryotes and viruses. Despite all evidence that Prp8 is an integral part of the spliceosomal catalytic center, much remains to be learned about its molecular functions and evolutionary origin. By analyzing sequence and structure similarities between Prp8 and other protein domains, we show that its N-terminal region contains a putative bromodomain. The central conserved domain of Prp8 is related to the catalytic domain of reverse transcriptases (RTs) and is most similar to homologous enzymes encoded by prokaryotic retroelements. However, putative catalytic residues in this RT domain are only partially conserved and may not be sufficient for the nucleotidyltransferase activity. The RT domain is followed by an uncharacterized sequence region with relatives found in fungal RT-like proteins. This part of Prp8 is predicted to adopt an α-helical structure and may be functionally equivalent to diverse maturase/X domains of retroelements and to the thumb domain of retroviral RTs. Together with a previously identified C-terminal domain that has an RNaseH-like fold, our results suggest evolutionary connections between Prp8 and ancient mobile elements. Prp8 may have evolved by acquiring nucleic acid-binding domains from inactivated retroelements, and their present-day role may be in maintaining proper conformation of the bound RNA cofactors and substrates of the splicing reaction. This is only the second example-the other one being telomerase-of the RT recruitment from a genomic parasite to serve an essential cellular function.
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Affiliation(s)
- Mensur Dlakić
- Department of Microbiology, Montana State University, Bozeman, Montana 59717, USA.
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42
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Valadkhan S, Jaladat Y. The spliceosomal proteome: at the heart of the largest cellular ribonucleoprotein machine. Proteomics 2010; 10:4128-41. [PMID: 21080498 DOI: 10.1002/pmic.201000354] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Almost all primary transcripts in higher eukaryotes undergo several splicing events and alternative splicing is a major factor in generating proteomic diversity. Thus, the spliceosome, the ribonucleoprotein assembly that performs splicing, is a highly critical cellular machine and as expected, a very complex one. Indeed, the spliceosome is one of the largest, if not the largest, molecular machine in the cell with over 150 different components in human. A large fraction of the spliceosomal proteome is organized into small nuclear ribonucleoprotein particles by associating with one of the small nuclear RNAs, and the function of many spliceosomal proteins revolve around their association or interaction with the spliceosomal RNAs or the substrate pre-messenger RNAs. In addition to the complex web of protein-RNA interactions, an equally complex network of protein-protein interactions exists in the spliceosome, which includes a number of large, conserved proteins with critical functions in the spliceosomal catalytic core. These include the largest conserved nuclear protein, Prp8, which plays a critical role in spliceosomal function in a hitherto unknown manner. Taken together, the large spliceosomal proteome and its dynamic nature has made it a highly challenging system to study, and at the same time, provides an exciting example of the evolution of a proteome around a backbone of primordial RNAs likely dating from the RNA World.
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Affiliation(s)
- Saba Valadkhan
- Center for RNA Molecular Biology, Case Western Reserve University, Cleveland, OH 44113, USA.
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43
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Hogg R, McGrail JC, O'Keefe RT. The function of the NineTeen Complex (NTC) in regulating spliceosome conformations and fidelity during pre-mRNA splicing. Biochem Soc Trans 2010; 38:1110-5. [PMID: 20659013 PMCID: PMC4234902 DOI: 10.1042/bst0381110] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The NineTeen Complex (NTC) of proteins associates with the spliceosome during pre-mRNA splicing and is essential for both steps of intron removal. The NTC and other NTC-associated proteins are recruited to the spliceosome where they participate in regulating the formation and progression of essential spliceosome conformations required for the two steps of splicing. It is now clear that the NTC is an integral component of active spliceosomes from yeast to humans and provides essential support for the spliceosomal snRNPs (small nuclear ribonucleoproteins). In the present article, we discuss the identification and characterization of the yeast NTC and review recent work in yeast that supports the essential role for this complex in the regulation and fidelity of splicing.
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Affiliation(s)
- Rebecca Hogg
- Faculty of Life Sciences, Michael Smith Building, The University of Manchester, Manchester M13 9PT, UK
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The pre-mRNA splicing machinery of trypanosomes: complex or simplified? EUKARYOTIC CELL 2010; 9:1159-70. [PMID: 20581293 DOI: 10.1128/ec.00113-10] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Trypanosomatids are early-diverged, protistan parasites of which Trypanosoma brucei, Trypanosoma cruzi, and several species of Leishmania cause severe, often lethal diseases in humans. To better combat these parasites, their molecular biology has been a research focus for more than 3 decades, and the discovery of spliced leader (SL) trans splicing in T. brucei established a key difference between parasites and hosts. In SL trans splicing, the capped 5'-terminal region of the small nuclear SL RNA is fused onto the 5' end of each mRNA. This process, in conjunction with polyadenylation, generates individual mRNAs from polycistronic precursors and creates functional mRNA by providing the cap structure. The reaction is a two-step transesterification process analogous to intron removal by cis splicing which, in trypanosomatids, is confined to very few pre-mRNAs. Both types of pre-mRNA splicing are carried out by the spliceosome, consisting of five U-rich small nuclear RNAs (U snRNAs) and, in humans, up to approximately 170 different proteins. While trypanosomatids possess a full set of spliceosomal U snRNAs, only a few splicing factors were identified by standard genome annotation because trypanosomatid amino acid sequences are among the most divergent in the eukaryotic kingdom. This review focuses on recent progress made in the characterization of the splicing factor repertoire in T. brucei, achieved by tandem affinity purification of splicing complexes, by systematic analysis of proteins containing RNA recognition motifs, and by mining the genome database. In addition, recent findings about functional differences between trypanosome and human pre-mRNA splicing factors are discussed.
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45
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Current awareness on yeast. Yeast 2010. [DOI: 10.1002/yea.1717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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46
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Khanna M, Van Bakel H, Tang X, Calarco JA, Babak T, Guo G, Emili A, Greenblatt JF, Hughes TR, Krogan NJ, Blencowe BJ. A systematic characterization of Cwc21, the yeast ortholog of the human spliceosomal protein SRm300. RNA (NEW YORK, N.Y.) 2009; 15:2174-85. [PMID: 19789211 PMCID: PMC2779666 DOI: 10.1261/rna.1790509] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Cwc21 (complexed with Cef1 protein 21) is a 135 amino acid yeast protein that shares homology with the N-terminal domain of human SRm300/SRRM2, a large serine/arginine-repeat protein shown previously to associate with the splicing coactivator and 3'-end processing stimulatory factor, SRm160. Proteomic analysis of spliceosomal complexes has suggested a role for Cwc21 and SRm300 at the core of the spliceosome. However, specific functions for these proteins have remained elusive. In this report, we employ quantitative genetic interaction mapping, mass spectrometry of tandem affinity-purified complexes, and microarray profiling to investigate genetic, physical, and functional interactions involving Cwc21. Combined data from these assays support multiple roles for Cwc21 in the formation and function of splicing complexes. Consistent with a role for Cwc21 at the core of the spliceosome, we observe strong genetic, physical, and functional interactions with Isy1, a protein previously implicated in the first catalytic step of splicing and splicing fidelity. Together, the results suggest multiple functions for Cwc21/SRm300 in the splicing process, including an important role in the activation of splicing in association with Isy1.
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Affiliation(s)
- May Khanna
- Banting and Best Department of Medical Research, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
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