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O'Neill AC, Uzbas F, Antognolli G, Merino F, Draganova K, Jäck A, Zhang S, Pedini G, Schessner JP, Cramer K, Schepers A, Metzger F, Esgleas M, Smialowski P, Guerrini R, Falk S, Feederle R, Freytag S, Wang Z, Bahlo M, Jungmann R, Bagni C, Borner GHH, Robertson SP, Hauck SM, Götz M. Spatial centrosome proteome of human neural cells uncovers disease-relevant heterogeneity. Science 2022; 376:eabf9088. [PMID: 35709258 DOI: 10.1126/science.abf9088] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The centrosome provides an intracellular anchor for the cytoskeleton, regulating cell division, cell migration, and cilia formation. We used spatial proteomics to elucidate protein interaction networks at the centrosome of human induced pluripotent stem cell-derived neural stem cells (NSCs) and neurons. Centrosome-associated proteins were largely cell type-specific, with protein hubs involved in RNA dynamics. Analysis of neurodevelopmental disease cohorts identified a significant overrepresentation of NSC centrosome proteins with variants in patients with periventricular heterotopia (PH). Expressing the PH-associated mutant pre-mRNA-processing factor 6 (PRPF6) reproduced the periventricular misplacement in the developing mouse brain, highlighting missplicing of transcripts of a microtubule-associated kinase with centrosomal location as essential for the phenotype. Collectively, cell type-specific centrosome interactomes explain how genetic variants in ubiquitous proteins may convey brain-specific phenotypes.
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Affiliation(s)
- Adam C O'Neill
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU), Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany
| | - Fatma Uzbas
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU), Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany
| | - Giulia Antognolli
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU), Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany
| | - Florencia Merino
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU), Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany
| | - Kalina Draganova
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU), Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany
| | - Alex Jäck
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU), Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany
| | - Sirui Zhang
- CAS Key Laboratory of Computational Biology, Biomedical Big Data Center, Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai 200031, China.,University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China.,CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Giorgia Pedini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
| | | | - Kimberly Cramer
- Max Planck Institute of Biochemistry, Martinsried, Germany.,Faculty of Physics and Center for Nanoscience, LMU, Munich, Germany
| | - Aloys Schepers
- Monoclonal Antibody Core Facility, Institute for Diabetes and Obesity, Helmholtz Center Munich, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Fabian Metzger
- Research Unit Protein Science and Metabolomics and Proteomics Core, Helmholtz Centre Munich, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Miriam Esgleas
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU), Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany
| | - Pawel Smialowski
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU), Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany
| | - Renzo Guerrini
- Neuroscience Department, Children's Hospital Meyer-University of Florence, Florence, Italy
| | - Sven Falk
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU), Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany
| | - Regina Feederle
- Monoclonal Antibody Core Facility, Institute for Diabetes and Obesity, Helmholtz Center Munich, German Research Center for Environmental Health, 85764 Neuherberg, Germany.,SYNERGY, Excellence Cluster of Systems Neurology, Biomedical Center, LMU, Planegg-Martinsried, Germany
| | - Saskia Freytag
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Zefeng Wang
- CAS Key Laboratory of Computational Biology, Biomedical Big Data Center, Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai 200031, China.,University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China.,CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Melanie Bahlo
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Ralf Jungmann
- Max Planck Institute of Biochemistry, Martinsried, Germany.,Faculty of Physics and Center for Nanoscience, LMU, Munich, Germany
| | - Claudia Bagni
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy.,Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | | | - Stephen P Robertson
- Department of Women's and Children's Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Stefanie M Hauck
- Research Unit Protein Science and Metabolomics and Proteomics Core, Helmholtz Centre Munich, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Magdalena Götz
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians-Universitaet (LMU), Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany.,Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Großhaderner Straße 9, 82152 Planegg-Martinsried, Germany.,SYNERGY, Excellence Cluster of Systems Neurology, Biomedical Center, LMU, Planegg-Martinsried, Germany
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2
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An Allosteric Network for Spliceosome Activation Revealed by High-Throughput Suppressor Analysis in Saccharomyces cerevisiae. Genetics 2019; 212:111-124. [PMID: 30898770 DOI: 10.1534/genetics.119.301922] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/15/2019] [Indexed: 12/30/2022] Open
Abstract
Selection of suppressor mutations that correct growth defects caused by substitutions in an RNA or protein can reveal functionally important molecular structures and interactions in living cells. This approach is particularly useful for the study of complex biological pathways involving many macromolecules, such as premessenger RNA (pre-mRNA) splicing. When a sufficiently large number of suppressor mutations is obtained and structural information is available, it is possible to generate detailed models of molecular function. However, the laborious and expensive task of identifying suppressor mutations in whole-genome selections limits the utility of this approach. Here I show that a custom targeted sequencing panel can greatly accelerate the identification of suppressor mutations in the Saccharomyces cerevisiae genome. Using a panel that targets 112 genes encoding pre-mRNA splicing factors, I identified 27 unique mutations in six protein-coding genes that each overcome the cold-sensitive block to spliceosome activation caused by a substitution in U4 small nuclear RNA. When mapped to existing structures of spliceosomal complexes, the identified suppressors implicate specific molecular contacts between the proteins Brr2, Prp6, Prp8, Prp31, Sad1, and Snu114 as functionally important in an early step of catalytic activation of the spliceosome. This approach shows great promise for elucidating the allosteric cascade of molecular interactions that direct accurate and efficient pre-mRNA splicing and should be broadly useful for understanding the dynamics of other complex biological assemblies or pathways.
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3
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Wei S, Bian Y, Zhao Q, Chen S, Mao J, Song C, Cheng K, Xiao Z, Zhang C, Ma W, Zou H, Ye M, Dai S. Salinity-Induced Palmella Formation Mechanism in Halotolerant Algae Dunaliella salina Revealed by Quantitative Proteomics and Phosphoproteomics. FRONTIERS IN PLANT SCIENCE 2017; 8:810. [PMID: 28588593 PMCID: PMC5441111 DOI: 10.3389/fpls.2017.00810] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 04/30/2017] [Indexed: 05/05/2023]
Abstract
Palmella stage is critical for some unicellular algae to survive in extreme environments. The halotolerant algae Dunaliella salina is a good single-cell model for studying plant adaptation to high salinity. To investigate the molecular adaptation mechanism in salinity shock-induced palmella formation, we performed a comprehensive physiological, proteomics and phosphoproteomics study upon palmella formation of D. salina using dimethyl labeling and Ti4+-immobilized metal ion affinity chromatography (IMAC) proteomic approaches. We found that 151 salinity-responsive proteins and 35 salinity-responsive phosphoproteins were involved in multiple signaling and metabolic pathways upon palmella formation. Taken together with photosynthetic parameters and enzyme activity analyses, the patterns of protein accumulation and phosphorylation level exhibited the mechanisms upon palmella formation, including dynamics of cytoskeleton and cell membrane curvature, accumulation and transport of exopolysaccharides, photosynthesis and energy supplying (i.e., photosystem II stability and activity, cyclic electron transport, and C4 pathway), nuclear/chloroplastic gene expression regulation and protein processing, reactive oxygen species homeostasis, and salt signaling transduction. The salinity-responsive protein-protein interaction (PPI) networks implied that signaling and protein synthesis and fate are crucial for modulation of these processes. Importantly, the 3D structure of phosphoprotein clearly indicated that the phosphorylation sites of eight proteins were localized in the region of function domain.
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Affiliation(s)
- Sijia Wei
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration in Oil Field, Alkali Soil Natural Environmental Science Center, Ministry of Education, Northeast Forestry UniversityHarbin, China
| | - Yangyang Bian
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of SciencesDalian, China
| | - Qi Zhao
- College of Life and Environmental Sciences, Shanghai Normal UniversityShanghai, China
| | - Sixue Chen
- Department of Biology, Genetics Institute, Plant Molecular and Cellular Biology Program, Interdisciplinary Center for Biotechnology Research, University of FloridaGainesville, FL, Unites States
| | - Jiawei Mao
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of SciencesDalian, China
| | - Chunxia Song
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of SciencesDalian, China
| | - Kai Cheng
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of SciencesDalian, China
| | - Zhen Xiao
- College of Life and Environmental Sciences, Shanghai Normal UniversityShanghai, China
| | - Chuanfang Zhang
- College of Life and Environmental Sciences, Shanghai Normal UniversityShanghai, China
| | - Weimin Ma
- College of Life and Environmental Sciences, Shanghai Normal UniversityShanghai, China
| | - Hanfa Zou
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of SciencesDalian, China
| | - Mingliang Ye
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of SciencesDalian, China
- *Correspondence: Mingliang Ye
| | - Shaojun Dai
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration in Oil Field, Alkali Soil Natural Environmental Science Center, Ministry of Education, Northeast Forestry UniversityHarbin, China
- College of Life and Environmental Sciences, Shanghai Normal UniversityShanghai, China
- Shaojun Dai
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4
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Eckert D, Andrée N, Razanau A, Zock-Emmenthal S, Lützelberger M, Plath S, Schmidt H, Guerra-Moreno A, Cozzuto L, Ayté J, Käufer NF. Prp4 Kinase Grants the License to Splice: Control of Weak Splice Sites during Spliceosome Activation. PLoS Genet 2016; 12:e1005768. [PMID: 26730850 PMCID: PMC4701394 DOI: 10.1371/journal.pgen.1005768] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 12/03/2015] [Indexed: 12/02/2022] Open
Abstract
The genome of the fission yeast Schizosaccharomyces pombe encodes 17 kinases that are essential for cell growth. These include the cell-cycle regulator Cdc2, as well as several kinases that coordinate cell growth, polarity, and morphogenesis during the cell cycle. In this study, we further characterized another of these essential kinases, Prp4, and showed that the splicing of many introns is dependent on Prp4 kinase activity. For detailed characterization, we chose the genes res1 and ppk8, each of which contains one intron of typical size and position. Splicing of the res1 intron was dependent on Prp4 kinase activity, whereas splicing of the ppk8 intron was not. Extensive mutational analyses of the 5’ splice site of both genes revealed that proper transient interaction with the 5’ end of snRNA U1 governs the dependence of splicing on Prp4 kinase activity. Proper transient interaction between the branch sequence and snRNA U2 was also important. Therefore, the Prp4 kinase is required for recognition and efficient splicing of introns displaying weak exon1/5’ splice sites and weak branch sequences. Prp4 is an essential protein kinase that is involved in the splicing of some introns. Using a conditional mutant of Prp4, we showed that a subset of genes, including several cell cycle–regulatory genes, are dependent on Prp4 for splicing. Furthermore, we could convert genes between Prp4-dependent and -independent states by introducing single-nucleotide mutations in the exon1/5’ splice sites and branch sequence of introns. This work shows that Prp4 activity is required for splicing surveillance in a subset of mRNAs.
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Affiliation(s)
- Daniela Eckert
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Nicole Andrée
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Aleh Razanau
- Department of Physiology and Pathophysiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
| | | | - Martin Lützelberger
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Susann Plath
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Henning Schmidt
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Angel Guerra-Moreno
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Luca Cozzuto
- CRG Bioinformatics Core, Centre de Regulació Genòmica (CRG), and Universitat Pompeu Fabra, Barcelona, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
- * E-mail: (JA); (NFK)
| | - Norbert F. Käufer
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
- * E-mail: (JA); (NFK)
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5
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Maita H, Tomita K, Ariga H. A split luciferase-based reporter for detection of a cellular macromolecular complex. Anal Biochem 2014; 452:1-9. [PMID: 24503441 DOI: 10.1016/j.ab.2014.01.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 01/21/2014] [Accepted: 01/24/2014] [Indexed: 11/16/2022]
Abstract
The spliceosome is a highly dynamic macromolecular ribonucleoprotein (RNP) machine that catalyzes pre-mRNA splicing by assembling U1, U2, U4, U5, and U6 small nuclear RNPs (snRNPs). To process large numbers of introns with a limited number of snRNPs, synthesis and recycling of snRNPs must be maintained within an appropriate range to avoid their shortage. However, the mechanism that maintains cellular snRNP levels is unknown. Molecules that modulate cellular snRNP levels may help to define this mechanism but are not available. Therefore, the goal of the current study was to develop a reporter for snRNP levels using split luciferase based on proteomic analysis of snRNPs. We constructed an expression library of a luciferase fragment fused to core components of U5 snRNP and used it to isolate pre-mRNA processing factor 6 (PRPF6) and small nuclear ribonucleoprotein 40 kDa (U5-40K) that specifically reconstitute luciferase activity in the U5 snRNP complex. Here we show that this reporter detects the effects of small molecules on the levels of the U5 snRNP reporter protein complex. Our approach provides an alternative assay to discover small molecules targeting a macromolecular complex when the structure of the complex is not precisely identified.
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Affiliation(s)
- Hiroshi Maita
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0812, Japan.
| | - Kenji Tomita
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0812, Japan
| | - Hiroyoshi Ariga
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0812, Japan
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6
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Livesay SB, Collier SE, Bitton DA, Bähler J, Ohi MD. Structural and functional characterization of the N terminus of Schizosaccharomyces pombe Cwf10. EUKARYOTIC CELL 2013; 12:1472-89. [PMID: 24014766 PMCID: PMC3837936 DOI: 10.1128/ec.00140-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/03/2013] [Indexed: 01/10/2023]
Abstract
The spliceosome is a dynamic macromolecular machine that catalyzes the removal of introns from pre-mRNA, yielding mature message. Schizosaccharomyces pombe Cwf10 (homolog of Saccharomyces cerevisiae Snu114 and human U5-116K), an integral member of the U5 snRNP, is a GTPase that has multiple roles within the splicing cycle. Cwf10/Snu114 family members are highly homologous to eukaryotic translation elongation factor EF2, and they contain a conserved N-terminal extension (NTE) to the EF2-like portion, predicted to be an intrinsically unfolded domain. Using S. pombe as a model system, we show that the NTE is not essential, but cells lacking this domain are defective in pre-mRNA splicing. Genetic interactions between cwf10-ΔNTE and other pre-mRNA splicing mutants are consistent with a role for the NTE in spliceosome activation and second-step catalysis. Characterization of Cwf10-NTE by various biophysical techniques shows that in solution the NTE contains regions of both structure and disorder. The first 23 highly conserved amino acids of the NTE are essential for its role in splicing but when overexpressed are not sufficient to restore pre-mRNA splicing to wild-type levels in cwf10-ΔNTE cells. When the entire NTE is overexpressed in the cwf10-ΔNTE background, it can complement the truncated Cwf10 protein in trans, and it immunoprecipitates a complex similar in composition to the late-stage U5.U2/U6 spliceosome. These data show that the structurally flexible NTE is capable of independently incorporating into the spliceosome and improving splicing function, possibly indicating a role for the NTE in stabilizing conformational rearrangements during a splice cycle.
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Affiliation(s)
- S. Brent Livesay
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Scott E. Collier
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Danny A. Bitton
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Jürg Bähler
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Melanie D. Ohi
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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7
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Splicing functions and global dependency on fission yeast slu7 reveal diversity in spliceosome assembly. Mol Cell Biol 2013; 33:3125-36. [PMID: 23754748 DOI: 10.1128/mcb.00007-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The multiple short introns in Schizosaccharomyces pombe genes with degenerate cis sequences and atypically positioned polypyrimidine tracts make an interesting model to investigate canonical and alternative roles for conserved splicing factors. Here we report functions and interactions of the S. pombe slu7(+) (spslu7(+)) gene product, known from Saccharomyces cerevisiae and human in vitro reactions to assemble into spliceosomes after the first catalytic reaction and to dictate 3' splice site choice during the second reaction. By using a missense mutant of this essential S. pombe factor, we detected a range of global splicing derangements that were validated in assays for the splicing status of diverse candidate introns. We ascribe widespread, intron-specific SpSlu7 functions and have deduced several features, including the branch nucleotide-to-3' splice site distance, intron length, and the impact of its A/U content at the 5' end on the intron's dependence on SpSlu7. The data imply dynamic substrate-splicing factor relationships in multiintron transcripts. Interestingly, the unexpected early splicing arrest in spslu7-2 revealed a role before catalysis. We detected a salt-stable association with U5 snRNP and observed genetic interactions with spprp1(+), a homolog of human U5-102k factor. These observations together point to an altered recruitment and dependence on SpSlu7, suggesting its role in facilitating transitions that promote catalysis, and highlight the diversity in spliceosome assembly.
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8
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Jiang QT, Liu T, Ma J, Wei YM, Lu ZX, Lan XJ, Dai SF, Zheng YL. Characterization of barley Prp1 gene and its expression during seed development and under abiotic stress. Genetica 2012; 139:1283-92. [PMID: 22290495 DOI: 10.1007/s10709-012-9630-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 01/13/2012] [Indexed: 11/30/2022]
Abstract
The pre-mRNA processing (Prp1) gene encodes a spliceosomal protein. It was firstly identified in fission yeast and plays a regular role during spliceosome activation and cell cycle. Plant Prp1 genes have only been identified from rice, Sorghum and Arabidopsis thaliana. In this study, we reported the identification and isolation of a novel Prp1 gene from barley, and further explored its expressional pattern by using real-time quantitative RTPCR, promoter prediction and analysis of microarray data. The putative barley Prp1 protein has a similar primary structure features to those of other known Prp1 protein in this family. The results of amino acid comparison indicated that Prp1 protein of barley and other plant species has a highly conserved 30 termnal region while their 50 sequences greatly varied. The results of expressional analysis revealed that the expression level of barley Prp1 gene is always stable in different vegetative tissues, except it is up-regulated at the mid- and late stages of seed development or under the condition of cold stress. This kind of expressional pattern for barley Prp1 is also supported by our results of comparison of microarray data from barley, rice and Arabidopsis. For the molecular mechanism of its expressional pattern, we conclude that the expression of Prp1 gene may be up-regulated by the increase of pre-mRNAs and not be constitutive or ubiquitous.
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Affiliation(s)
- Qian-Tao Jiang
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
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9
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A quantitative high-throughput in vitro splicing assay identifies inhibitors of spliceosome catalysis. Mol Cell Biol 2012; 32:1271-83. [PMID: 22252314 DOI: 10.1128/mcb.05788-11] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Despite intensive research, there are very few reagents with which to modulate and dissect the mRNA splicing pathway. Here, we describe a novel approach to identify such tools, based on detection of the exon junction complex (EJC), a unique molecular signature that splicing leaves on mRNAs. We developed a high-throughput, splicing-dependent EJC immunoprecipitation (EJIPT) assay to quantitate mRNAs spliced from biotin-tagged pre-mRNAs in cell extracts, using antibodies to EJC components Y14 and eukaryotic translation initiation factor 4aIII (eIF4AIII). Deploying EJIPT we performed high-throughput screening (HTS) in conjunction with secondary assays to identify splicing inhibitors. We describe the identification of 1,4-naphthoquinones and 1,4-heterocyclic quinones with known anticancer activity as potent and selective splicing inhibitors. Interestingly, and unlike previously described small molecules, most of which target early steps, our inhibitors represented by the benzothiazole-4,7-dione, BN82685, block the second of two trans-esterification reactions in splicing, preventing the release of intron lariat and ligation of exons. We show that BN82685 inhibits activated spliceosomes' elaborate structural rearrangements that are required for second-step catalysis, allowing definition of spliceosomes stalled in midcatalysis. EJIPT provides a platform for characterization and discovery of splicing and EJC modulators.
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10
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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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Tanackovic G, Ransijn A, Thibault P, Abou Elela S, Klinck R, Berson EL, Chabot B, Rivolta C. PRPF mutations are associated with generalized defects in spliceosome formation and pre-mRNA splicing in patients with retinitis pigmentosa. Hum Mol Genet 2011; 20:2116-30. [PMID: 21378395 PMCID: PMC3090192 DOI: 10.1093/hmg/ddr094] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 02/08/2011] [Accepted: 03/01/2011] [Indexed: 01/22/2023] Open
Abstract
Proteins PRPF31, PRPF3 and PRPF8 (RP-PRPFs) are ubiquitously expressed components of the spliceosome, a macromolecular complex that processes nearly all pre-mRNAs. Although these spliceosomal proteins are conserved in eukaryotes and are essential for survival, heterozygous mutations in human RP-PRPF genes lead to retinitis pigmentosa, a hereditary disease restricted to the eye. Using cells from patients with 10 different mutations, we show that all clinically relevant RP-PRPF defects affect the stoichiometry of spliceosomal small nuclear RNAs (snRNAs), the protein composition of tri-small nuclear ribonucleoproteins and the kinetics of spliceosome assembly. These mutations cause inefficient splicing in vitro and affect constitutive splicing ex-vivo by impairing the removal of at least 9% of endogenously expressed introns. Alternative splicing choices are also affected when RP-PRPF defects are present. Furthermore, we show that the steady-state levels of snRNAs and processed pre-mRNAs are highest in the retina, indicating a particularly elevated splicing activity. Our results suggest a role for PRPFs defects in the etiology of PRPF-linked retinitis pigmentosa, which appears to be a truly systemic splicing disease. Although these mutations cause widespread and important splicing defects, they are likely tolerated by the majority of human tissues but are critical for retinal cell survival.
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Affiliation(s)
- Goranka Tanackovic
- Department of Medical Genetics, University of Lausanne, Lausanne 1005, Switzerland
| | - Adriana Ransijn
- Department of Medical Genetics, University of Lausanne, Lausanne 1005, Switzerland
| | - Philippe Thibault
- Laboratoire de génomique fonctionnelle de l'Université de Sherbrooke, Sherbrooke, Canada
| | - Sherif Abou Elela
- Laboratoire de génomique fonctionnelle de l'Université de Sherbrooke, Sherbrooke, Canada
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, CanadaJ1H 5N4 and
| | - Roscoe Klinck
- Laboratoire de génomique fonctionnelle de l'Université de Sherbrooke, Sherbrooke, Canada
| | - Eliot L. Berson
- The Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA
| | - Benoit Chabot
- Laboratoire de génomique fonctionnelle de l'Université de Sherbrooke, Sherbrooke, Canada
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, CanadaJ1H 5N4 and
| | - Carlo Rivolta
- Department of Medical Genetics, University of Lausanne, Lausanne 1005, Switzerland
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