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Borao S, Vega M, Boronat S, Hidalgo E, Hümmer S, Ayté J. A systematic screen identifies Saf5 as a link between splicing and transcription in fission yeast. PLoS Genet 2024; 20:e1011316. [PMID: 38833506 PMCID: PMC11178228 DOI: 10.1371/journal.pgen.1011316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 06/14/2024] [Accepted: 05/23/2024] [Indexed: 06/06/2024] Open
Abstract
Splicing is an important step of gene expression regulation in eukaryotes, as there are many mRNA precursors that can be alternatively spliced in different tissues, at different cell cycle phases or under different external stimuli. We have developed several integrated fluorescence-based in vivo splicing reporter constructs that allow the quantification of fission yeast splicing in vivo on intact cells, and we have compared their splicing efficiency in a wild type strain and in a prp2-1 (U2AF65) genetic background, showing a clear dependency between Prp2 and a consensus signal at 5' splicing site (5'SS). To isolate novel genes involved in regulated splicing, we have crossed the reporter showing more intron retention with the Schizosaccharomyces pombe knock out collection. Among the candidate genes involved in the regulation of splicing, we have detected strong splicing defects in two of the mutants -Δcwf12, a member of the NineTeen Complex (NTC) and Δsaf5, a methylosome subunit that acts together with the survival motor neuron (SMN) complex in small nuclear ribonucleoproteins (snRNP) biogenesis. We have identified that strains with mutations in cwf12 have inefficient splicing, mainly when the 5'SS differs from the consensus. However, although Δsaf5 cells also have some dependency on 5'SS sequence, we noticed that when one intron of a given pre-mRNA was affected, the rest of the introns of the same pre-mRNA had high probabilities of being also affected. This observation points Saf5 as a link between transcription rate and splicing.
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Affiliation(s)
- Sonia Borao
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Montserrat Vega
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Susanna Boronat
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Stefan Hümmer
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
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2
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Cipakova I, Jurcik M, Selicky T, Lalakova LO, Jakubikova J, Cipak L. Dysfunction of Gpl1-Gih35-Wdr83 Complex in S. pombe Affects the Splicing of DNA Damage Repair Factors Resulting in Increased Sensitivity to DNA Damage. Int J Mol Sci 2024; 25:4192. [PMID: 38673778 PMCID: PMC11049892 DOI: 10.3390/ijms25084192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/08/2024] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
Pre-mRNA splicing plays a key role in the regulation of gene expression. Recent discoveries suggest that defects in pre-mRNA splicing, resulting from the dysfunction of certain splicing factors, can impact the expression of genes crucial for genome surveillance mechanisms, including those involved in cellular response to DNA damage. In this study, we analyzed how cells with a non-functional spliceosome-associated Gpl1-Gih35-Wdr83 complex respond to DNA damage. Additionally, we investigated the role of this complex in regulating the splicing of factors involved in DNA damage repair. Our findings reveal that the deletion of any component within the Gpl1-Gih35-Wdr83 complex leads to a significant accumulation of unspliced pre-mRNAs of DNA repair factors. Consequently, mutant cells lacking this complex exhibit increased sensitivity to DNA-damaging agents. These results highlight the importance of the Gpl1-Gih35-Wdr83 complex in regulating the expression of DNA repair factors, thereby protecting the stability of the genome following DNA damage.
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Affiliation(s)
- Ingrid Cipakova
- Department of Genetics, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 84505 Bratislava, Slovakia; (M.J.); (T.S.); (L.O.L.)
| | - Matus Jurcik
- Department of Genetics, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 84505 Bratislava, Slovakia; (M.J.); (T.S.); (L.O.L.)
| | - Tomas Selicky
- Department of Genetics, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 84505 Bratislava, Slovakia; (M.J.); (T.S.); (L.O.L.)
| | - Laura Olivia Lalakova
- Department of Genetics, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 84505 Bratislava, Slovakia; (M.J.); (T.S.); (L.O.L.)
| | - Jana Jakubikova
- Department of Tumor Immunology, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 84505 Bratislava, Slovakia;
| | - Lubos Cipak
- Department of Genetics, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 84505 Bratislava, Slovakia; (M.J.); (T.S.); (L.O.L.)
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3
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Hu Y, Hou Y, Zhou S, Wang Y, Shen C, Mu L, Su D, Zhang R. Mechanism of assembly of snRNP cores assisted by ICln and the SMN complex in fission yeast. iScience 2023; 26:107604. [PMID: 37664592 PMCID: PMC10470402 DOI: 10.1016/j.isci.2023.107604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/11/2023] [Accepted: 08/08/2023] [Indexed: 09/05/2023] Open
Abstract
The spliceosomal snRNP cores, each comprised of a snRNA and a seven-membered Sm ring (D1/D2/F/E/G/D3/B), are assembled by twelve chaperoning proteins in human. However, only six assembly-assisting proteins, ICln and the SMN complex (SMN/Gemin2/Gemin6-8), have been found in Schizosaccharomyces pombe (Sp). Here, we used recombinant proteins to reconstitute the chaperone machinery and investigated the roles of these proteins systematically. We found that, like the human system, the assembly in S. pombe requires ICln and the SMN complex sequentially. However, there are several significant differences. For instance, h_F/E/G forms heterohexamers and heterotrimers, while Sp_F/E/G only forms heterohexamers; h_Gemin2 alone can bind D1/D2/F/E/G, but Sp_Gemin2 cannot. Moreover, we found that Sp_Gemin2 is essential using genetic approaches. These mechanistic studies reveal that these six proteins are necessary and sufficient for Sm core assembly at the molecular level, and enrich our understanding of the chaperone systems in species variation and evolution.
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Affiliation(s)
- Yan Hu
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Yan Hou
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Shijie Zhou
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Yingzhi Wang
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Congcong Shen
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Li Mu
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Dan Su
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
| | - Rundong Zhang
- Department of Ophthalmology, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu 610041, P.R. China
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4
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Willems P, Van Ruyskensvelde V, Maruta T, Pottie R, Fernández-Fernández ÁD, Pauwels J, Hannah MA, Gevaert K, Van Breusegem F, Van der Kelen K. Mutation of Arabidopsis SME1 and Sm core assembly improves oxidative stress resilience. Free Radic Biol Med 2023; 200:117-129. [PMID: 36870374 DOI: 10.1016/j.freeradbiomed.2023.02.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/18/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023]
Abstract
Alternative splicing is a key posttranscriptional gene regulatory process, acting in diverse adaptive and basal plant processes. Splicing of precursor-messenger RNA (pre-mRNA) is catalyzed by a dynamic ribonucleoprotein complex, designated the spliceosome. In a suppressor screen, we identified a nonsense mutation in the Smith (Sm) antigen protein SME1 to alleviate photorespiratory H2O2-dependent cell death in catalase deficient plants. Similar attenuation of cell death was observed upon chemical inhibition of the spliceosome, suggesting pre-mRNA splicing inhibition to be responsible for the observed cell death alleviation. Furthermore, the sme1-2 mutants showed increased tolerance to the reactive oxygen species inducing herbicide methyl viologen. Both an mRNA-seq and shotgun proteomic analysis in sme1-2 mutants displayed a constitutive molecular stress response, together with extensive alterations in pre-mRNA splicing of transcripts encoding metabolic enzymes and RNA binding proteins, even under unstressed conditions. Using SME1 as a bait to identify protein interactors, we provide experimental evidence for almost 50 homologs of the mammalian spliceosome-associated protein to reside in the Arabidopsis thaliana spliceosome complexes and propose roles in pre-mRNA splicing for four uncharacterized plant proteins. Furthermore, as for sme1-2, a mutant in the Sm core assembly protein ICLN resulted in a decreased sensitivity to methyl viologen. Taken together, these data show that both a perturbed Sm core composition and assembly results in the activation of a defense response and in enhanced resilience to oxidative stress.
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Affiliation(s)
- Patrick Willems
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052, Ghent, Belgium; Center for Plant Systems Biology, VIB, Technologiepark 71, 9052, Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Technologiepark 75, 9052, Ghent, Belgium; Center for Medical Biotechnology, VIB, Technologiepark 75, 9052, Ghent, Belgium.
| | - Valerie Van Ruyskensvelde
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052, Ghent, Belgium; Center for Plant Systems Biology, VIB, Technologiepark 71, 9052, Ghent, Belgium.
| | - Takanori Maruta
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052, Ghent, Belgium; Center for Plant Systems Biology, VIB, Technologiepark 71, 9052, Ghent, Belgium; Department of Life Sciences, Faculty of Life and Environmental Sciences, Shimane University, 1060 Nishikawatsu-cho, Matsue, Shimane, 690-8504, Japan.
| | - Robin Pottie
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052, Ghent, Belgium; Center for Plant Systems Biology, VIB, Technologiepark 71, 9052, Ghent, Belgium.
| | - Álvaro D Fernández-Fernández
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052, Ghent, Belgium; Center for Plant Systems Biology, VIB, Technologiepark 71, 9052, Ghent, Belgium.
| | - Jarne Pauwels
- Department of Biomolecular Medicine, Ghent University, Technologiepark 75, 9052, Ghent, Belgium; Center for Medical Biotechnology, VIB, Technologiepark 75, 9052, Ghent, Belgium.
| | - Matthew A Hannah
- BASF Belgium Coordination Center, Innovation Center Gent, Technologiepark 101, 9052, Ghent, Belgium.
| | - Kris Gevaert
- Department of Biomolecular Medicine, Ghent University, Technologiepark 75, 9052, Ghent, Belgium; Center for Medical Biotechnology, VIB, Technologiepark 75, 9052, Ghent, Belgium.
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052, Ghent, Belgium; Center for Plant Systems Biology, VIB, Technologiepark 71, 9052, Ghent, Belgium.
| | - Katrien Van der Kelen
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052, Ghent, Belgium; Center for Plant Systems Biology, VIB, Technologiepark 71, 9052, Ghent, Belgium.
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5
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Mateos JL, Sanchez SE, Legris M, Esteve-Bruna D, Torchio JC, Petrillo E, Goretti D, Blanco-Touriñán N, Seymour DK, Schmid M, Weigel D, Alabadí D, Yanovsky MJ. PICLN modulates alternative splicing and light/temperature responses in plants. PLANT PHYSIOLOGY 2023; 191:1036-1051. [PMID: 36423226 PMCID: PMC9922395 DOI: 10.1093/plphys/kiac527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 10/01/2022] [Indexed: 06/16/2023]
Abstract
Plants undergo transcriptome reprograming to adapt to daily and seasonal fluctuations in light and temperature conditions. While most efforts have focused on the role of master transcription factors, the importance of splicing factors modulating these processes is now emerging. Efficient pre-mRNA splicing depends on proper spliceosome assembly, which in plants and animals requires the methylosome complex. Ion Chloride nucleotide-sensitive protein (PICLN) is part of the methylosome complex in both humans and Arabidopsis (Arabidopsis thaliana), and we show here that the human PICLN ortholog rescues phenotypes of Arabidopsis picln mutants. Altered photomorphogenic and photoperiodic responses in Arabidopsis picln mutants are associated with changes in pre-mRNA splicing that partially overlap with those in PROTEIN ARGININE METHYL TRANSFERASE5 (prmt5) mutants. Mammalian PICLN also acts in concert with the Survival Motor Neuron (SMN) complex component GEMIN2 to modulate the late steps of UsnRNP assembly, and many alternative splicing events regulated by PICLN but not PRMT5, the main protein of the methylosome, are controlled by Arabidopsis GEMIN2. As with GEMIN2 and SM PROTEIN E1/PORCUPINE (SME1/PCP), low temperature, which increases PICLN expression, aggravates morphological and molecular defects of picln mutants. Taken together, these results establish a key role for PICLN in the regulation of pre-mRNA splicing and in mediating plant adaptation to daily and seasonal fluctuations in environmental conditions.
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Affiliation(s)
- Julieta L Mateos
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires–Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1405BWE, Argentina
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-UBA-CONICET) and Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires C1428EHA, Argentina
- RNA Biology and Molecular Physiology, Faculty of Biology, Bielefeld University, Biele-feld 33615, Germany
| | - Sabrina E Sanchez
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires–Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1405BWE, Argentina
| | - Martina Legris
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires–Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1405BWE, Argentina
- Department of Molecular Biology, Max Planck Institute for Biology Tübingen, Tübingen 72076, Germany
| | - David Esteve-Bruna
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politecnica de Valencia), Valencia 46022, Spain
| | - Jeanette C Torchio
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires–Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1405BWE, Argentina
| | - Ezequiel Petrillo
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-UBA-CONICET) and Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires C1428EHA, Argentina
| | - Daniela Goretti
- Department of Plant Physiology, Umea Plant Science Centre, Umea University, Umea SE-901 87, Sweden
| | - Noel Blanco-Touriñán
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politecnica de Valencia), Valencia 46022, Spain
| | - Danelle K Seymour
- Department of Molecular Biology, Max Planck Institute for Biology Tübingen, Tübingen 72076, Germany
| | - Markus Schmid
- Department of Plant Physiology, Umea Plant Science Centre, Umea University, Umea SE-901 87, Sweden
| | - Detlef Weigel
- Department of Molecular Biology, Max Planck Institute for Biology Tübingen, Tübingen 72076, Germany
| | - David Alabadí
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politecnica de Valencia), Valencia 46022, Spain
| | - Marcelo J Yanovsky
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires–Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1405BWE, Argentina
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6
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Veepaschit J, Viswanathan A, Bordonné R, Grimm C, Fischer U. Identification and structural analysis of the Schizosaccharomyces pombe SMN complex. Nucleic Acids Res 2021; 49:7207-7223. [PMID: 33754639 PMCID: PMC8287938 DOI: 10.1093/nar/gkab158] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/11/2021] [Accepted: 02/26/2021] [Indexed: 01/20/2023] Open
Abstract
The macromolecular SMN complex facilitates the formation of Sm-class ribonucleoproteins involved in mRNA processing (UsnRNPs). While biochemical studies have revealed key activities of the SMN complex, its structural investigation is lagging behind. Here we report on the identification and structural determination of the SMN complex from the lower eukaryote Schizosaccharomyces pombe, consisting of SMN, Gemin2, 6, 7, 8 and Sm proteins. The core of the SMN complex is formed by several copies of SMN tethered through its C-terminal alpha-helices arranged with alternating polarity. This creates a central platform onto which Gemin8 binds and recruits Gemins 6 and 7. The N-terminal parts of the SMN molecules extrude via flexible linkers from the core and enable binding of Gemin2 and Sm proteins. Our data identify the SMN complex as a multivalent hub where Sm proteins are collected in its periphery to allow their joining with UsnRNA.
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Affiliation(s)
- Jyotishman Veepaschit
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg 97074, Germany
| | - Aravindan Viswanathan
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg 97074, Germany
| | - Rémy Bordonné
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier 34293, France
| | - Clemens Grimm
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg 97074, Germany
| | - Utz Fischer
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg 97074, Germany
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7
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Antoine M, Patrick KL, Soret J, Duc P, Rage F, Cacciottolo R, Nissen KE, Cauchi RJ, Krogan NJ, Guthrie C, Gachet Y, Bordonné R. Splicing Defects of the Profilin Gene Alter Actin Dynamics in an S. pombe SMN Mutant. iScience 2019; 23:100809. [PMID: 31927482 PMCID: PMC6957872 DOI: 10.1016/j.isci.2019.100809] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 09/13/2019] [Accepted: 12/23/2019] [Indexed: 12/18/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating motor neuron disorder caused by mutations in the survival motor neuron (SMN) gene. It remains unclear how SMN deficiency leads to the loss of motor neurons. By screening Schizosaccharomyces pombe, we found that the growth defect of an SMN mutant can be alleviated by deletion of the actin-capping protein subunit gene acp1+. We show that SMN mutated cells have splicing defects in the profilin gene, which thus directly hinder actin cytoskeleton homeostasis including endocytosis and cytokinesis. We conclude that deletion of acp1+ in an SMN mutant background compensates for actin cytoskeleton alterations by restoring redistribution of actin monomers between different types of cellular actin networks. Our data reveal a direct correlation between an impaired function of SMN in snRNP assembly and defects in actin dynamics. They also point to important common features in the pathogenic mechanism of SMA and ALS. Splicing defects in the profilin gene in an S. pombe SMN mutant SMN mutant contains excessively polymerized actin Altered actin dynamics in the SMN mutant hinders endocytosis and cytokinesis Deletion of the acp1 subunit restores actin dynamics in the SMN mutant
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Affiliation(s)
- Marie Antoine
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | | | - Johann Soret
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Pauline Duc
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Florence Rage
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Rebecca Cacciottolo
- Department of Physiology and Biochemistry, University of Malta, Msida, Malta
| | | | - Ruben J Cauchi
- Department of Physiology and Biochemistry, University of Malta, Msida, Malta
| | | | | | - Yannick Gachet
- Centre de Biologie Integrative, University of Toulouse, CNRS, Toulouse, France
| | - Rémy Bordonné
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France.
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8
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Prusty AB, Meduri R, Prusty BK, Vanselow J, Schlosser A, Fischer U. Impaired spliceosomal UsnRNP assembly leads to Sm mRNA down-regulation and Sm protein degradation. J Cell Biol 2017. [PMID: 28637748 PMCID: PMC5551706 DOI: 10.1083/jcb.201611108] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cellular spliceosomal UsnRNP assembly is assisted by the PRMT5 and SMN complexes. Prusty et al. demonstrate that perturbations in the assembly machinery of UsnRNPs trigger complex cellular responses, using ribosomes, exosome-mediated RNA degradation, and autophagy to prevent Sm protein aggregation. Specialized assembly factors facilitate the formation of many macromolecular complexes in vivo. The formation of Sm core structures of spliceosomal U-rich small nuclear ribonucleoprotein particles (UsnRNPs) requires assembly factors united in protein arginine methyltransferase 5 (PRMT5) and survival motor neuron (SMN) complexes. We demonstrate that perturbations of this assembly machinery trigger complex cellular responses that prevent aggregation of unassembled Sm proteins. Inactivation of the SMN complex results in the initial tailback of Sm proteins on the PRMT5 complex, followed by down-regulation of their encoding mRNAs. In contrast, reduction of pICln, a PRMT5 complex subunit, leads to the retention of newly synthesized Sm proteins on ribosomes and their subsequent lysosomal degradation. Overexpression of Sm proteins under these conditions results in a surplus of Sm proteins over pICln, promoting their aggregation. Our studies identify an elaborate safeguarding system that prevents individual Sm proteins from aggregating, contributing to cellular UsnRNP homeostasis.
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Affiliation(s)
| | - Rajyalakshmi Meduri
- Department of Biochemistry, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Bhupesh Kumar Prusty
- Department of Microbiology, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Jens Vanselow
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Andreas Schlosser
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Utz Fischer
- Department of Biochemistry, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany .,Department of Radiation Medicine and Applied Sciences, University of California at San Diego, San Diego, CA
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9
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Huang S, Balgi A, Pan Y, Li M, Zhang X, Du L, Zhou M, Roberge M, Li X. Identification of Methylosome Components as Negative Regulators of Plant Immunity Using Chemical Genetics. MOLECULAR PLANT 2016; 9:1620-1633. [PMID: 27756575 DOI: 10.1016/j.molp.2016.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 09/01/2016] [Accepted: 10/01/2016] [Indexed: 06/06/2023]
Abstract
Nucleotide-binding leucine-rich repeat (NLR) proteins serve as immune receptors in both plants and animals. To identify components required for NLR-mediated immunity, we designed and carried out a chemical genetics screen to search for small molecules that can alter immune responses in Arabidopsis thaliana. From 13 600 compounds, we identified Ro 8-4304 that was able to specifically suppress the severe autoimmune phenotypes of chs3-2D (chilling sensitive 3, 2D), including the arrested growth morphology and heightened PR (Pathogenesis Related) gene expression. Further, six Ro 8-4304 insensitive mutants were uncovered from the Ro 8-4304-insensitive mutant (rim) screen using a mutagenized chs3-2D population. Positional cloning revealed that rim1 encodes an allele of AtICln (I, currents; Cl, chloride; n, nucleotide). Genetic and biochemical analysis demonstrated that AtICln is in the same protein complex with the methylosome components small nuclear ribonucleoprotein D3b (SmD3b) and protein arginine methyltransferase 5 (PRMT5), which are required for the biogenesis of small nuclear ribonucleoproteins (snRNPs) involved in mRNA splicing. Double mutant analysis revealed that SmD3b is also involved in the sensitivity to Ro 8-4304, and the prmt5-1 chs3-2D double mutant is lethal. Loss of AtICln, SmD3b, or PRMT5 function results in enhanced disease resistance against the virulent oomycete pathogen Hyaloperonospora arabidopsidis Noco2, suggesting that mRNA splicing plays a previously unknown negative role in plant immunity. The successful implementation of a high-throughput chemical genetic screen and the identification of a small-molecule compound affecting plant immunity indicate that chemical genetics is a powerful tool to study whole-organism plant defense pathways.
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Affiliation(s)
- Shuai Huang
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Aruna Balgi
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Yaping Pan
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Meng Li
- Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Xiaoran Zhang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Lilin Du
- National Institute of Biological Sciences, Beijing 102206, China
| | - Ming Zhou
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Michel Roberge
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Xin Li
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
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10
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Borg RM, Fenech Salerno B, Vassallo N, Bordonne R, Cauchi RJ. Disruption of snRNP biogenesis factors Tgs1 and pICln induces phenotypes that mirror aspects of SMN-Gemins complex perturbation in Drosophila, providing new insights into spinal muscular atrophy. Neurobiol Dis 2016; 94:245-58. [PMID: 27388936 DOI: 10.1016/j.nbd.2016.06.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 06/20/2016] [Accepted: 06/27/2016] [Indexed: 01/27/2023] Open
Abstract
The neuromuscular disorder, spinal muscular atrophy (SMA), results from insufficient levels of the survival motor neuron (SMN) protein. Together with Gemins 2-8 and Unrip, SMN forms the large macromolecular SMN-Gemins complex, which is known to be indispensable for chaperoning the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs). It remains unclear whether disruption of this function is responsible for the selective neuromuscular degeneration in SMA. In the present study, we first show that loss of wmd, the Drosophila Unrip orthologue, has a negative impact on the motor system. However, due to lack of a functional relationship between wmd/Unrip and Gemin3, it is likely that Unrip joined the SMN-Gemins complex only recently in evolution. Second, we uncover that disruption of either Tgs1 or pICln, two cardinal players in snRNP biogenesis, results in viability and motor phenotypes that closely resemble those previously uncovered on loss of the constituent members of the SMN-Gemins complex. Interestingly, overexpression of both factors leads to motor dysfunction in Drosophila, a situation analogous to that of Gemin2. Toxicity is conserved in the yeast S. pombe where pICln overexpression induces a surplus of Sm proteins in the cytoplasm, indicating that a block in snRNP biogenesis is partly responsible for this phenotype. Importantly, we show a strong functional relationship and a physical interaction between Gemin3 and either Tgs1 or pICln. We propose that snRNP biogenesis is the pathway connecting the SMN-Gemins complex to a functional neuromuscular system, and its disturbance most likely leads to the motor dysfunction that is typical in SMA.
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Affiliation(s)
- Rebecca M Borg
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, Msida, Malta; Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Université Montpellier 1 and 2, Montpellier, France
| | - Benji Fenech Salerno
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, Msida, Malta
| | - Neville Vassallo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, Msida, Malta
| | - Rémy Bordonne
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Université Montpellier 1 and 2, Montpellier, France
| | - Ruben J Cauchi
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, Msida, Malta.
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11
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Borg RM, Bordonne R, Vassallo N, Cauchi RJ. Genetic Interactions between the Members of the SMN-Gemins Complex in Drosophila. PLoS One 2015; 10:e0130974. [PMID: 26098872 PMCID: PMC4476591 DOI: 10.1371/journal.pone.0130974] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 05/27/2015] [Indexed: 11/19/2022] Open
Abstract
The SMN-Gemins complex is composed of Gemins 2–8, Unrip and the survival motor neuron (SMN) protein. Limiting levels of SMN result in the neuromuscular disorder, spinal muscular atrophy (SMA), which is presently untreatable. The most-documented function of the SMN-Gemins complex concerns the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs). Despite multiple genetic studies, the Gemin proteins have not been identified as prominent modifiers of SMN-associated mutant phenotypes. In the present report, we make use of the Drosophila model organism to investigate whether viability and motor phenotypes associated with a hypomorphic Gemin3 mutant are enhanced by changes in the levels of SMN, Gemin2 and Gemin5 brought about by various genetic manipulations. We show a modifier effect by all three members of the minimalistic fly SMN-Gemins complex within the muscle compartment of the motor unit. Interestingly, muscle-specific overexpression of Gemin2 was by itself sufficient to depress normal motor function and its enhanced upregulation in all tissues leads to a decline in fly viability. The toxicity associated with increased Gemin2 levels is conserved in the yeast S. pombe in which we find that the cytoplasmic retention of Sm proteins, likely reflecting a block in the snRNP assembly pathway, is a contributing factor. We propose that a disruption in the normal stoichiometry of the SMN-Gemins complex depresses its function with consequences that are detrimental to the motor system.
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Affiliation(s)
- Rebecca M. Borg
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta GC
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Université Montpellier 1 and 2, Montpellier, France
| | - Rémy Bordonne
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Université Montpellier 1 and 2, Montpellier, France
| | - Neville Vassallo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta GC
| | - Ruben J. Cauchi
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta GC
- * E-mail:
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