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Krausová M, Kreplová M, Banik P, Cvačková Z, Kubovčiak J, Modrák M, Zudová D, Lindovský J, Kubik-Zahorodna A, Pálková M, Kolář M, Procházka J, Sedláček R, Staněk D. Retinitis pigmentosa-associated mutations in mouse Prpf8 cause misexpression of circRNAs and degeneration of cerebellar granule cells. Life Sci Alliance 2023; 6:e202201855. [PMID: 37019475 PMCID: PMC10078954 DOI: 10.26508/lsa.202201855] [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: 11/25/2022] [Revised: 03/21/2023] [Accepted: 03/21/2023] [Indexed: 04/07/2023] Open
Abstract
A subset of patients with retinitis pigmentosa (RP) carry mutations in several spliceosomal components including the PRPF8 protein. Here, we established two alleles of murine Prpf8 that genocopy or mimic aberrant PRPF8 found in RP patients-the substitution p.Tyr2334Asn and an extended protein variant p.Glu2331ValfsX15. Homozygous mice expressing the aberrant Prpf8 variants developed within the first 2 mo progressive atrophy of the cerebellum because of extensive granule cell loss, whereas other cerebellar cells remained unaffected. We further show that a subset of circRNAs were deregulated in the cerebellum of both Prpf8-RP mouse strains. To identify potential risk factors that sensitize the cerebellum for Prpf8 mutations, we monitored the expression of several splicing proteins during the first 8 wk. We observed down-regulation of all selected splicing proteins in the WT cerebellum, which coincided with neurodegeneration onset. The decrease in splicing protein expression was further pronounced in mouse strains expressing mutated Prpf8. Collectively, we propose a model where physiological reduction in spliceosomal components during postnatal tissue maturation sensitizes cells to the expression of aberrant Prpf8 and the subsequent deregulation of circRNAs triggers neuronal death.
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Affiliation(s)
- Michaela Krausová
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Michaela Kreplová
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Poulami Banik
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Zuzana Cvačková
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Kubovčiak
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Modrák
- Core Facility Bioinformatics, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Dagmar Zudová
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec, Czech Republic
| | - Jiří Lindovský
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec, Czech Republic
| | - Agnieszka Kubik-Zahorodna
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec, Czech Republic
| | - Marcela Pálková
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec, Czech Republic
| | - Michal Kolář
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Procházka
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec, Czech Republic
| | - Radislav Sedláček
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, Vestec, Czech Republic
| | - David Staněk
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
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Nazlamova L, Villa Vasquez SS, Lord J, Karthik V, Cheung MK, Lakowski J, Wheway G. Microtubule modification defects underlie cilium degeneration in cell models of retinitis pigmentosa associated with pre-mRNA splicing factor mutations. Front Genet 2022; 13:1009430. [PMID: 36176300 PMCID: PMC9513239 DOI: 10.3389/fgene.2022.1009430] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 08/19/2022] [Indexed: 11/17/2022] Open
Abstract
Retinitis pigmentosa (RP) is the most common cause of hereditary blindness, and may occur in isolation as a non-syndromic condition or alongside other features in a syndromic presentation. Biallelic or monoallelic mutations in one of eight genes encoding pre-mRNA splicing factors are associated with non-syndromic RP. The molecular mechanism of disease remains incompletely understood, limiting opportunities for targeted treatment. Here we use CRISPR and base edited PRPF6 and PRPF31 mutant cell lines, and publicly-available data from human PRPF31+/− patient derived retinal organoids and PRPF31 siRNA-treated organotypic retinal cultures to confirm an enrichment of differential splicing of microtubule, centrosomal, cilium and DNA damage response pathway genes in these cells. We show that genes with microtubule/centrosome/centriole/cilium gene ontology terms are enriched for weak 3′ and 5′ splice sites, and that subtle defects in spliceosome activity predominantly affect efficiency of splicing of these exons. We suggest that the primary defect in PRPF6 or PRPF31 mutant cells is microtubule and centrosomal defects, leading to defects in cilium and mitotic spindle stability, with the latter leading to DNA damage, triggering differential splicing of DNA damage response genes to activate this pathway. Finally, we expand understanding of “splicing factor RP” by investigating the function of TTLL3, one of the most statistically differentially expressed genes in PRPF6 and PRPF31 mutant cells. We identify that TTLL3 is the only tubulin glycylase expressed in the human retina, essential for monoglycylation of microtubules of the cilium, including the retinal photoreceptor cilium, to prevent cilium degeneration and retinal degeneration. Our preliminary data suggest that rescue of tubulin glycylation through overexpression of TTLL3 is sufficient to rescue cilium number in PRPF6 and PRPF31 mutant cells, suggesting that this defect underlies the cellular defect and may represent a potential target for therapeutic intervention in this group of disorders.
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Affiliation(s)
- Liliya Nazlamova
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Suly Saray Villa Vasquez
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Jenny Lord
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Varshini Karthik
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Man-Kim Cheung
- Centre for Research in Biosciences, University of the West of England, Bristol, United Kingdom
| | - Jörn Lakowski
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Gabrielle Wheway
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
- *Correspondence: Gabrielle Wheway,
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Obuća M, Cvačková Z, Kubovčiak J, Kolář M, Staněk D. Retinitis pigmentosa-linked mutation in DHX38 modulates its splicing activity. PLoS One 2022; 17:e0265742. [PMID: 35385551 PMCID: PMC8985939 DOI: 10.1371/journal.pone.0265742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 03/07/2022] [Indexed: 01/21/2023] Open
Abstract
Retinitis pigmentosa (RP) is a hereditary disease affecting tens of thousands of people world-wide. Here we analyzed the effect of an amino acid substitution in the RNA helicase DHX38 (Prp16) causing RP. DHX38 has been proposed as the helicase important for the 2nd step of splicing. We showed that DHX38 associates with key splicing factors involved in both splicing steps but did not find any evidence that the RP mutations changes DHX38 interaction profile with the spliceosome. We further downregulated DHX38 and monitored changes in splicing. We observed only minor perturbations of general splicing but detected modulation of ~70 alternative splicing events. Next, we probed DHX38 function in splicing of retina specific genes and found that FSCN2 splicing is dependent on DHX38. In addition, RHO splicing was inhibited specifically by expression of DHX38 RP variant. Finally, we showed that overexpression of DHX38 promotes usage of canonical as well as cryptic 5' splice sites in HBB splicing reporter. Together, our data show that DHX38 is a splicing factor that promotes splicing of cryptic splice sites and regulate alternative splicing. We further provide evidence that the RP-linked substitution G332D modulates DHX38 splicing activity.
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Affiliation(s)
- Mina Obuća
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Zuzana Cvačková
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Kubovčiak
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Michal Kolář
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - David Staněk
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- * E-mail:
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The Alter Retina: Alternative Splicing of Retinal Genes in Health and Disease. Int J Mol Sci 2021; 22:ijms22041855. [PMID: 33673358 PMCID: PMC7917623 DOI: 10.3390/ijms22041855] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 12/14/2022] Open
Abstract
Alternative splicing of mRNA is an essential mechanism to regulate and increase the diversity of the transcriptome and proteome. Alternative splicing frequently occurs in a tissue- or time-specific manner, contributing to differential gene expression between cell types during development. Neural tissues present extremely complex splicing programs and display the highest number of alternative splicing events. As an extension of the central nervous system, the retina constitutes an excellent system to illustrate the high diversity of neural transcripts. The retina expresses retinal specific splicing factors and produces a large number of alternative transcripts, including exclusive tissue-specific exons, which require an exquisite regulation. In fact, a current challenge in the genetic diagnosis of inherited retinal diseases stems from the lack of information regarding alternative splicing of retinal genes, as a considerable percentage of mutations alter splicing or the relative production of alternative transcripts. Modulation of alternative splicing in the retina is also instrumental in the design of novel therapeutic approaches for retinal dystrophies, since it enables precision medicine for specific mutations.
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Roithová A, Feketová Z, Vaňáčová Š, Staněk D. DIS3L2 and LSm proteins are involved in the surveillance of Sm ring-deficient snRNAs. Nucleic Acids Res 2020; 48:6184-6197. [PMID: 32374871 PMCID: PMC7293007 DOI: 10.1093/nar/gkaa301] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 04/06/2020] [Accepted: 04/23/2020] [Indexed: 01/31/2023] Open
Abstract
Spliceosomal small nuclear ribonucleoprotein particles (snRNPs) undergo a complex maturation pathway containing multiple steps in the nucleus and in the cytoplasm. snRNP biogenesis is strictly proofread and several quality control checkpoints are placed along the pathway. Here, we analyzed the fate of small nuclear RNAs (snRNAs) that are unable to acquire a ring of Sm proteins. We showed that snRNAs lacking the Sm ring are unstable and accumulate in P-bodies in an LSm1-dependent manner. We further provide evidence that defective snRNAs without the Sm binding site are uridylated at the 3′ end and associate with DIS3L2 3′→5′ exoribonuclease and LSm proteins. Finally, inhibition of 5′→3′ exoribonuclease XRN1 increases association of ΔSm snRNAs with DIS3L2, which indicates competition and compensation between these two degradation enzymes. Together, we provide evidence that defective snRNAs without the Sm ring are uridylated and degraded by alternative pathways involving either DIS3L2 or LSm proteins and XRN1.
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Affiliation(s)
- Adriana Roithová
- Laboratory of RNA Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic.,Faculty of Science, Charles University, 128 00 Prague, Czech Republic
| | - Zuzana Feketová
- CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5/A35, 625 00 Brno, Czech Republic
| | - Štěpánka Vaňáčová
- CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5/A35, 625 00 Brno, Czech Republic
| | - David Staněk
- Laboratory of RNA Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic
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Valdés-Sánchez L, Calado SM, de la Cerda B, Aramburu A, García-Delgado AB, Massalini S, Montero-Sánchez A, Bhatia V, Rodríguez-Bocanegra E, Diez-Lloret A, Rodríguez-Martínez D, Chakarova C, Bhattacharya SS, Díaz-Corrales FJ. Retinal pigment epithelium degeneration caused by aggregation of PRPF31 and the role of HSP70 family of proteins. Mol Med 2019; 26:1. [PMID: 31892304 PMCID: PMC6938640 DOI: 10.1186/s10020-019-0124-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 12/05/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Mutations in pre-mRNA splicing factor PRPF31 can lead to retinitis pigmentosa (RP). Although the exact disease mechanism remains unknown, it has been hypothesized that haploinsufficiency might be involved in the pathophysiology of the disease. METHODS In this study, we have analyzed a mouse model containing the p.A216P mutation in Prpf31 gene. RESULTS We found that mutant Prpf31 protein produces cytoplasmic aggregates in the retinal pigment epithelium and decreasing the protein levels of this splicing factor in the nucleus. Additionally, normal protein was recruited in insoluble aggregates when the mutant protein was overexpressed in vitro. In response to protein aggregation, Hspa4l is overexpressed. This member of the HSP70 family of chaperones might contribute to the correct folding and solubilization of the mutant protein, allowing its translocation to the nucleus. CONCLUSIONS Our data suggests that a mechanism haploinsufficiency and dominant-negative is involved in retinal degeneration due to mutations in PRPF31. HSP70 over-expression might be a new therapeutic target for the treatment of retinal degeneration due to PRPF31 mutations.
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Affiliation(s)
- Lourdes Valdés-Sánchez
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Sofia M Calado
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
- Present Address: Center for Biomedical Research (CBMR), University of Algarve, 8800-139, Faro, Portugal
| | - Berta de la Cerda
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Ana Aramburu
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
- Present Address: Clinique de l'Oeil, Avenue Bois de la Chapelle 15, 1213, Onex, Switzerland
| | - Ana Belén García-Delgado
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Simone Massalini
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
- Present Address: Center for Molecular and Cellular Bioengineering (CMCB) DFG-Research Center for Regenerative Therapies Dresden (CRTD) Cluster of Excellence, Technische Universität Dresden, Fetscherstraße, 105 01307, Dresden, Germany
| | - Adoración Montero-Sánchez
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Vaibhav Bhatia
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Eduardo Rodríguez-Bocanegra
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
- Present Address: Universitätsklinikum Tübingen, Forschungsinstitut für Augenheilkunde, Elfriede-Aulhorn-Str. 7, 72076, Tübingen, Germany
| | - Andrea Diez-Lloret
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Daniel Rodríguez-Martínez
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Christina Chakarova
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Shom S Bhattacharya
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK.
| | - Francisco J Díaz-Corrales
- Regeneration and Cell Therapy Department, Andalusian Molecular Biology and Regenerative Medicine Centre-CABIMER (Junta de Andalucía), CSIC, Universidad de Sevilla, Universidad Pablo de Olavide, Avda. Americo Vespucio 24, 41092, Seville, Spain.
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Bhatia V, Valdés-Sánchez L, Rodriguez-Martinez D, Bhattacharya SS. Formation of 53BP1 foci and ATM activation under oxidative stress is facilitated by RNA:DNA hybrids and loss of ATM-53BP1 expression promotes photoreceptor cell survival in mice. F1000Res 2018; 7:1233. [PMID: 30345028 PMCID: PMC6171737 DOI: 10.12688/f1000research.15579.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/01/2018] [Indexed: 01/18/2023] Open
Abstract
Background: Photoreceptors, light-sensing neurons in retina, are central to vision. Photoreceptor cell death (PCD) is observed in most inherited and acquired retinal dystrophies. But the underlying molecular mechanism of PCD is unclear. Photoreceptors are sturdy neurons that survive high oxidative and phototoxic stress, which are known threats to genome stability. Unexpectedly, DNA damage response in mice photoreceptors is compromised; mainly due to loss of crucial DNA repair proteins, ATM and 53BP1. We tried to understand the molecular function of ATM and 53BP1 in response to oxidative stress and how suppression of DNA repair response in mice retina affect photoreceptor cell survival. Methods: We use the state of art cell biology methods and structure-function analysis of mice retina. RNA:DNA hybrids (S9.6 antibody and Hybrid-binding domain of RNaseH1) and DNA repair foci (gH2AX and 53BP1) are quantified by confocal microscopy, in retinal sections and cultured cell lines. Oxidative stress, DNA double strand break, RNaseH1 expression and small-molecule kinase-inhibitors were used to understand the role of ATM and RNA:DNA hybrids in DNA repair. Lastly, retinal structure and function of ATM deficient mice, in Retinal degeneration 1 (Pde6brd1) background, is studied using Immunohistochemistry and Electroretinography. Results: Our work has three novel findings: firstly, both human and mice photoreceptor cells specifically accumulate RNA:DNA hybrids, a structure formed by re-hybridization of nascent RNA with template DNA during transcription. Secondly, RNA:DNA-hybrids promote ataxia-telangiectasia mutated (ATM) activation during oxidative stress and 53BP1-foci formation during downstream DNA repair process. Thirdly, loss of ATM -in murine photoreceptors- protract DNA repair but also promote their survival. Conclusions: We propose that due to high oxidative stress and accumulation of RNA:DNA-hybrids in photoreceptors, expression of ATM is tightly regulated to prevent PCD. Inefficient regulation of ATM expression could be central to PCD and inhibition of ATM-activation could suppress PCD in retinal dystrophy patients.
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Affiliation(s)
- Vaibhav Bhatia
- CABIMER (Centro Andaluz de Biología Molecular y Medicina Regenerativa), (FPS) Fundacion Progreso y Salud, Sevilla, Andalucia, 41092, Spain
| | - Lourdes Valdés-Sánchez
- CABIMER (Centro Andaluz de Biología Molecular y Medicina Regenerativa), (FPS) Fundacion Progreso y Salud, Sevilla, Andalucia, 41092, Spain
| | - Daniel Rodriguez-Martinez
- CABIMER (Centro Andaluz de Biología Molecular y Medicina Regenerativa), (FPS) Fundacion Progreso y Salud, Sevilla, Andalucia, 41092, Spain
| | - Shom Shankar Bhattacharya
- CABIMER (Centro Andaluz de Biología Molecular y Medicina Regenerativa), (FPS) Fundacion Progreso y Salud, Sevilla, Andalucia, 41092, Spain
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8
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Roithová A, Klimešová K, Pánek J, Will CL, Lührmann R, Staněk D, Girard C. The Sm-core mediates the retention of partially-assembled spliceosomal snRNPs in Cajal bodies until their full maturation. Nucleic Acids Res 2018; 46:3774-3790. [PMID: 29415178 PMCID: PMC5909452 DOI: 10.1093/nar/gky070] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/19/2018] [Accepted: 01/25/2018] [Indexed: 01/23/2023] Open
Abstract
Cajal bodies (CBs) are nuclear non-membrane bound organelles where small nuclear ribonucleoprotein particles (snRNPs) undergo their final maturation and quality control before they are released to the nucleoplasm. However, the molecular mechanism how immature snRNPs are targeted and retained in CBs has yet to be described. Here, we microinjected and expressed various snRNA deletion mutants as well as chimeric 7SK, Alu or bacterial SRP non-coding RNAs and provide evidence that Sm and SMN binding sites are necessary and sufficient for CB localization of snRNAs. We further show that Sm proteins, and specifically their GR-rich domains, are important for accumulating snRNPs in CBs. Accordingly, core snRNPs containing the Sm proteins, but not naked snRNAs, restore the formation of CBs after their depletion. Finally, we show that immature but not fully assembled snRNPs are able to induce CB formation and that microinjection of an excess of U2 snRNP-specific proteins, which promotes U2 snRNP maturation, chases U2 snRNA from CBs. We propose that the accessibility of the Sm ring represents the molecular basis for the quality control of the final maturation of snRNPs and the sequestration of immature particles in CBs.
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Affiliation(s)
- Adriana Roithová
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Klára Klimešová
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Josef Pánek
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Cindy L Will
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | | | - David Staněk
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Cyrille Girard
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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9
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snRNP proteins in health and disease. Semin Cell Dev Biol 2017; 79:92-102. [PMID: 29037818 DOI: 10.1016/j.semcdb.2017.10.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/09/2017] [Accepted: 10/12/2017] [Indexed: 01/16/2023]
Abstract
Split gene architecture of most human genes requires removal of intervening sequences by mRNA splicing that occurs on large multiprotein complexes called spliceosomes. Mutations compromising several spliceosomal components have been recorded in degenerative syndromes and haematological neoplasia, thereby highlighting the importance of accurate splicing execution in homeostasis of assorted adult tissues. Moreover, insufficient splicing underlies defective development of craniofacial skeleton and upper extremities. This review summarizes recent advances in the understanding of splicing factor function deduced from cryo-EM structures. We combine these data with the characterization of splicing factors implicated in hereditary or somatic disorders, with a focus on potential functional consequences the mutations may elicit in spliceosome assembly and/or performance. Given aberrant splicing or perturbations in splicing efficiency substantially underpin disease pathogenesis, profound understanding of the mis-splicing principles may open new therapeutic vistas. In three major sections dedicated to retinal dystrophies, hereditary acrofacial syndromes, and haematological malignancies, we delineate the noticeable variety of conditions associated with dysfunctional splicing and accentuate recurrent patterns in splicing defects.
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10
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Malinová A, Cvačková Z, Matějů D, Hořejší Z, Abéza C, Vandermoere F, Bertrand E, Staněk D, Verheggen C. Assembly of the U5 snRNP component PRPF8 is controlled by the HSP90/R2TP chaperones. J Cell Biol 2017; 216:1579-1596. [PMID: 28515276 PMCID: PMC5461031 DOI: 10.1083/jcb.201701165] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/22/2017] [Accepted: 04/04/2017] [Indexed: 12/23/2022] Open
Abstract
The pre-mRNA splicing factor PRPF8 is a crucial component of the U5 snRNP. Using quantitative proteomics, Malinová et al. show that assembly of the U5 snRNP is controlled by the HSP90/R2TP chaperones and that Retinitis pigmentosa–associated mutations in PRPF8 impair PRPF8 quality control and U5 snRNP chaperone-mediated assembly. Splicing is catalyzed by the spliceosome, a complex of five major small nuclear ribonucleoprotein particles (snRNPs). The pre-mRNA splicing factor PRPF8 is a crucial component of the U5 snRNP, and together with EFTUD2 and SNRNP200, it forms a central module of the spliceosome. Using quantitative proteomics, we identified assembly intermediates containing PRPF8, EFTUD2, and SNRNP200 in association with the HSP90/R2TP complex, its ZNHIT2 cofactor, and additional proteins. HSP90 and R2TP bind unassembled U5 proteins in the cytoplasm, stabilize them, and promote the formation of the U5 snRNP. We further found that PRPF8 mutants causing Retinitis pigmentosa assemble less efficiently with the U5 snRNP and bind more strongly to R2TP, with one mutant retained in the cytoplasm in an R2TP-dependent manner. We propose that the HSP90/R2TP chaperone system promotes the assembly of a key module of U5 snRNP while assuring the quality control of PRPF8. The proteomics data further reveal new interactions between R2TP and the tuberous sclerosis complex (TSC), pointing to a potential link between growth signals and the assembly of key cellular machines.
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Affiliation(s)
- Anna Malinová
- Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic.,Faculty of Science, Charles University in Prague, 128 00 Prague, Czech Republic
| | - Zuzana Cvačková
- Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Daniel Matějů
- Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Zuzana Hořejší
- Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Claire Abéza
- Institut de Génétique Moléculaire de Montpellier, Centre National de la Recherche Scientifique, University of Montpellier, 34293 Montpellier, France
| | - Franck Vandermoere
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique, University of Montpellier, 34090 Montpellier, France
| | - Edouard Bertrand
- Institut de Génétique Moléculaire de Montpellier, Centre National de la Recherche Scientifique, University of Montpellier, 34293 Montpellier, France
| | - David Staněk
- Institute of Molecular Genetics, Czech Academy of Sciences, 142 20 Prague, Czech Republic
| | - Céline Verheggen
- Institut de Génétique Moléculaire de Montpellier, Centre National de la Recherche Scientifique, University of Montpellier, 34293 Montpellier, France
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11
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Abstract
A majority of human genes contain non-coding intervening sequences – introns that must be precisely excised from the pre-mRNA molecule. This event requires the coordinated action of five major small nuclear ribonucleoprotein particles (snRNPs) along with additional non-snRNP splicing proteins. Introns must be removed with nucleotidal precision, since even a single nucleotide mistake would result in a reading frame shift and production of a non-functional protein. Numerous human inherited diseases are caused by mutations that affect splicing, including mutations in proteins which are directly involved in splicing catalysis. One of the most common hereditary diseases associated with mutations in core splicing proteins is retinitis pigmentosa (RP). So far, mutations in more than 70 genes have been connected to RP. While the majority of mutated genes are expressed specifically in the retina, eight target genes encode for ubiquitous core snRNP proteins (Prpf3, Prpf4, Prpf6, Prpf8, Prpf31, and SNRNP200/Brr2) and splicing factors (RP9 and DHX38). Why mutations in spliceosomal proteins, which are essential in nearly every cell in the body, causes a disease that displays such a tissue-specific phenotype is currently a mystery. In this review, we recapitulate snRNP functions, summarize the missense mutations which are found in spliceosomal proteins as well as their impact on protein functions and discuss specific models which may explain why the retina is sensitive to these mutations.
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Affiliation(s)
- Šárka Růžičková
- a Department of RNA Biology , Institute of Molecular Genetics AS CR , Prague , Czech Republic
| | - David Staněk
- a Department of RNA Biology , Institute of Molecular Genetics AS CR , Prague , Czech Republic
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12
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Bizarro J, Dodré M, Huttin A, Charpentier B, Schlotter F, Branlant C, Verheggen C, Massenet S, Bertrand E. NUFIP and the HSP90/R2TP chaperone bind the SMN complex and facilitate assembly of U4-specific proteins. Nucleic Acids Res 2015; 43:8973-89. [PMID: 26275778 PMCID: PMC4605303 DOI: 10.1093/nar/gkv809] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 07/27/2015] [Indexed: 12/17/2022] Open
Abstract
The Sm proteins are loaded on snRNAs by the SMN complex, but how snRNP-specific proteins are assembled remains poorly characterized. U4 snRNP and box C/D snoRNPs have structural similarities. They both contain the 15.5K and proteins with NOP domains (PRP31 for U4, NOP56/58 for snoRNPs). Biogenesis of box C/D snoRNPs involves NUFIP and the HSP90/R2TP chaperone system and here, we explore the function of this machinery in U4 RNP assembly. We show that yeast Prp31 interacts with several components of the NUFIP/R2TP machinery, and that these interactions are separable from each other. In human cells, PRP31 mutants that fail to stably associate with U4 snRNA still interact with components of the NUFIP/R2TP system, indicating that these interactions precede binding of PRP31 to U4 snRNA. Knock-down of NUFIP leads to mislocalization of PRP31 and decreased association with U4. Moreover, NUFIP is associated with the SMN complex through direct interactions with Gemin3 and Gemin6. Altogether, our data suggest a model in which the NUFIP/R2TP system is connected with the SMN complex and facilitates assembly of U4 snRNP-specific proteins.
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Affiliation(s)
- Jonathan Bizarro
- Equipe labélisée Ligue contre le Cancer, Institut de Génétique Moléculaire de Montpellier, IGMM-UMR 5535 du CNRS-Université de Montpellier, 1919, route de Mende, 34293 Montpellier Cedex 5, France
| | - Maxime Dodré
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-Université de Lorraine, Biopôle de l'Université de Lorraine, avenue de la forêt de Haye, BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France
| | - Alexandra Huttin
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-Université de Lorraine, Biopôle de l'Université de Lorraine, avenue de la forêt de Haye, BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France
| | - Bruno Charpentier
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-Université de Lorraine, Biopôle de l'Université de Lorraine, avenue de la forêt de Haye, BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France
| | - Florence Schlotter
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-Université de Lorraine, Biopôle de l'Université de Lorraine, avenue de la forêt de Haye, BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France
| | - Christiane Branlant
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-Université de Lorraine, Biopôle de l'Université de Lorraine, avenue de la forêt de Haye, BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France
| | - Céline Verheggen
- Equipe labélisée Ligue contre le Cancer, Institut de Génétique Moléculaire de Montpellier, IGMM-UMR 5535 du CNRS-Université de Montpellier, 1919, route de Mende, 34293 Montpellier Cedex 5, France
| | - Séverine Massenet
- Ingénierie Moléculaire et Physiopathologie Articulaire, UMR 7365 CNRS-Université de Lorraine, Biopôle de l'Université de Lorraine, avenue de la forêt de Haye, BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France
| | - Edouard Bertrand
- Equipe labélisée Ligue contre le Cancer, Institut de Génétique Moléculaire de Montpellier, IGMM-UMR 5535 du CNRS-Université de Montpellier, 1919, route de Mende, 34293 Montpellier Cedex 5, France
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13
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Liu N, Huang H, Dou QP, Liu J. Inhibition of 19S proteasome-associated deubiquitinases by metal-containing compounds. Oncoscience 2015; 2:457-66. [PMID: 26097878 PMCID: PMC4468331 DOI: 10.18632/oncoscience.167] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 05/24/2015] [Indexed: 12/31/2022] Open
Abstract
Copper and gold complexes have clinical activity in several diseases including cancer. Recently, we have reported that the anti-cancer activity of copper (II) pyrithione CuPT and gold (I) complex auranofin is associated with targeting the 19S proteasome-associated deubiquitinases (DUBs), UCHL5 and USP14. Here we discuss metal DUB inhibitors in treating cancer and other diseases. (from Editor). Several copper and gold complexes have clinical activity in treating some human diseases including cancer. Recently, we have reported that the anti-cancer activity of copper (II) pyrithione CuPT and gold (I) complex auranofin is tightly associated with their ability to target and inhibit the 19S proteasome-associated deubiquitinases (DUBs), UCHL5 and USP14. In this article we review small molecule inhibitors of DUBs and 19S proteasome-associated DUBs. We then describe and discuss the ubique nature of CuPT and auranofin, which is inhibition of 19S proteasome-associated UCHL5 and USP14. We finally suggest the potential to develop novel, specific metal-based DUB inhibitors for treating cancer and other diseases.
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Affiliation(s)
- Ningning Liu
- State Key Lab of Respiratory Disease, Protein Modification and Degradation Lab, Department of Pathophysiology, Guangzhou Medical University, Guangdong, China ; Guangzhou Research Institute of Cardiovascular Disease, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Hongbiao Huang
- State Key Lab of Respiratory Disease, Protein Modification and Degradation Lab, Department of Pathophysiology, Guangzhou Medical University, Guangdong, China
| | - Q Ping Dou
- State Key Lab of Respiratory Disease, Protein Modification and Degradation Lab, Department of Pathophysiology, Guangzhou Medical University, Guangdong, China ; The Molecular Therapeutics Program, Barbara Ann Karmanos Cancer Institute, and Departments of Oncology, Pharmacology and Pathology, School of Medicine, Wayne State University, Detroit, Michigan, USA
| | - Jinbao Liu
- State Key Lab of Respiratory Disease, Protein Modification and Degradation Lab, Department of Pathophysiology, Guangzhou Medical University, Guangdong, China
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14
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SART3-Dependent Accumulation of Incomplete Spliceosomal snRNPs in Cajal Bodies. Cell Rep 2015; 10:429-440. [PMID: 25600876 DOI: 10.1016/j.celrep.2014.12.030] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 09/18/2014] [Accepted: 12/13/2014] [Indexed: 12/16/2022] Open
Abstract
Cajal bodies (CBs) are evolutionarily conserved nuclear structures involved in the metabolism of spliceosomal small nuclear ribonucleoprotein particles (snRNPs). CBs are not present in all cell types, and the trigger for their formation is not yet known. Here, we depleted cells of factors required for the final steps of snRNP assembly and assayed for the presence of stalled intermediates in CBs. We show that depletion induces formation of CBs in cells that normally lack these nuclear compartments, suggesting that CB nucleation is triggered by an imbalance in snRNP assembly. Accumulation of stalled intermediates in CBs depends on the di-snRNP assembly factor SART3. SART3 is required for both the induction of CB formation as well as the tethering of incomplete snRNPs to coilin, the CB scaffolding protein. We propose a model wherein SART3 monitors tri-snRNP assembly and sequesters incomplete particles in CBs, thereby allowing cells to maintain a homeostatic balance of mature snRNPs in the nucleoplasm.
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15
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Linder B, Hirmer A, Gal A, Rüther K, Bolz HJ, Winkler C, Laggerbauer B, Fischer U. Identification of a PRPF4 loss-of-function variant that abrogates U4/U6.U5 tri-snRNP integration and is associated with retinitis pigmentosa. PLoS One 2014; 9:e111754. [PMID: 25383878 PMCID: PMC4226509 DOI: 10.1371/journal.pone.0111754] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 09/30/2014] [Indexed: 12/19/2022] Open
Abstract
Pre-mRNA splicing by the spliceosome is an essential step in the maturation of nearly all human mRNAs. Mutations in six spliceosomal proteins, PRPF3, PRPF4, PRPF6, PRPF8, PRPF31 and SNRNP200, cause retinitis pigmentosa (RP), a disease characterized by progressive photoreceptor degeneration. All splicing factors linked to RP are constituents of the U4/U6.U5 tri-snRNP subunit of the spliceosome, suggesting that the compromised function of this particle may lead to RP. Here, we report the identification of the p.R192H variant of the tri-snRNP factor PRPF4 in a patient with RP. The mutation affects a highly conserved arginine residue that is crucial for PRPF4 function. Introduction of a corresponding mutation into the zebrafish homolog of PRPF4 resulted in a complete loss of function in vivo. A series of biochemical experiments suggested that p.R192H disrupts the binding interface between PRPF4 and its interactor PRPF3. This interferes with the ability of PRPF4 to integrate into the tri-snRNP, as shown in a human cell line and in zebrafish embryos. These data suggest that the p.R192H variant of PRPF4 represents a functional null allele. The resulting haploinsufficiency of PRPF4 compromises the function of the tri-snRNP, reinforcing the notion that this spliceosomal particle is of crucial importance in the physiology of the retina.
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Affiliation(s)
- Bastian Linder
- Department of Biochemistry, University of Würzburg, Würzburg, Germany
| | - Anja Hirmer
- Department of Biochemistry, University of Würzburg, Würzburg, Germany
| | - Andreas Gal
- Department of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Klaus Rüther
- Department of Ophthalmology, Sankt Gertrauden-Krankenhaus, Berlin, Germany
| | - Hanno Jörn Bolz
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
- Bioscientia Center for Human Genetics, Ingelheim, Germany
| | - Christoph Winkler
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | | | - Utz Fischer
- Department of Biochemistry, University of Würzburg, Würzburg, Germany
- * E-mail:
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16
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Stejskalová E, Staněk D. The splicing factor U1-70K interacts with the SMN complex and is required for nuclear gem integrity. J Cell Sci 2014; 127:3909-15. [PMID: 25052091 DOI: 10.1242/jcs.155838] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The nuclear SMN complex localizes to specific structures called nuclear gems. The loss of gems is a cellular marker for several neurodegenerative diseases. Here, we identify that the U1-snRNP-specific protein U1-70K localizes to nuclear gems, and we show that U1-70K is necessary for gem integrity. Furthermore, we show that the interaction between U1-70K and the SMN complex is RNA independent, and we map the SMN complex binding site to the unstructured N-terminal tail of U1-70K. Consistent with these results, the expression of the U1-70K N-terminal tail rescues gem formation. These findings show that U1-70K is an SMN-complex-associating protein, and they suggest a new function for U1-70K in the formation of nuclear gems.
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Affiliation(s)
- Eva Stejskalová
- Department of RNA Biology, Institute of Molecular Genetics AS CR, 142 20 Prague, Czech Republic Faculty of Science, Charles University in Prague, 128 43 Prague, Czech Republic
| | - David Staněk
- Department of RNA Biology, Institute of Molecular Genetics AS CR, 142 20 Prague, Czech Republic
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17
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Dušková E, Hnilicová J, Staněk D. CRE promoter sites modulate alternative splicing via p300-mediated histone acetylation. RNA Biol 2014; 11:865-74. [PMID: 25019513 DOI: 10.4161/rna.29441] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Histone acetylation modulates alternative splicing of several hundred genes. Here, we tested the role of the histone acetyltransferase p300 in alternative splicing and showed that knockdown of p300 promotes inclusion of the fibronectin (FN1) alternative EDB exon. p300 associates with CRE sites in the promoter via the CREB transcription factor. We created mini-gene reporters driven by an artificial promoter containing CRE sites. Both deletion and mutation of the CRE site affected EDB alternative splicing in the same manner as p300 knockdown. Next we showed that p300 controls histone H4 acetylation along the FN1 gene. Consistently, p300 depletion and CRE deletion/mutation both reduced histone H4 acetylation on mini-gene reporters. Finally, we provide evidence that the effect of CRE inactivation on H4 acetylation and alternative splicing is counteracted by the inhibition of histone deacetylases. Together, these data suggest that histone acetylation could be one of the mechanisms how promoter and promoter binding proteins influence alternative splicing.
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Affiliation(s)
- Eva Dušková
- Department of RNA Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic; Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Jarmila Hnilicová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - David Staněk
- Department of RNA Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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18
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Cvačková Z, Matějů D, Staněk D. Retinitis Pigmentosa Mutations ofSNRNP200Enhance Cryptic Splice-Site Recognition. Hum Mutat 2013; 35:308-17. [DOI: 10.1002/humu.22481] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 11/05/2013] [Indexed: 12/16/2022]
Affiliation(s)
- Zuzana Cvačková
- Laboratory of RNA Biology; Institute of Molecular Genetics ASCR; Prague 142 20 Czech Republic
| | - Daniel Matějů
- Laboratory of RNA Biology; Institute of Molecular Genetics ASCR; Prague 142 20 Czech Republic
| | - David Staněk
- Laboratory of RNA Biology; Institute of Molecular Genetics ASCR; Prague 142 20 Czech Republic
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19
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Novotny I, Podolská K, Blazíková M, Valásek LS, Svoboda P, Stanek D. Nuclear LSm8 affects number of cytoplasmic processing bodies via controlling cellular distribution of Like-Sm proteins. Mol Biol Cell 2012; 23:3776-85. [PMID: 22875987 PMCID: PMC3459855 DOI: 10.1091/mbc.e12-02-0085] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We show that depletion of nuclear Like-Sm 8 (LSm8) dramatically increases processing body (P-body) number, provide the explanation that LSm8 acts via the alteration of the nuclear–cytoplasmic distribution of LSm2–7 proteins, and propose a model that P-bodies form via self-organization. Processing bodies (P-bodies) are dynamic cytoplasmic structures involved in mRNA degradation, but the mechanism that governs their formation is poorly understood. In this paper, we address a role of Like-Sm (LSm) proteins in formation of P-bodies and provide evidence that depletion of nuclear LSm8 increases the number of P-bodies, while LSm8 overexpression leads to P-body loss. We show that LSm8 knockdown causes relocalization of LSm4 and LSm6 proteins to the cytoplasm and suggest that LSm8 controls nuclear accumulation of all LSm2–7 proteins. We propose a model in which redistribution of LSm2–7 to the cytoplasm creates new binding sites for other P-body components and nucleates new, microscopically visible structures. The model is supported by prolonged residence of two P-body proteins, DDX6 and Ago2, in P-bodies after LSm8 depletion, which indicates stronger interactions between these proteins and P-bodies. Finally, an increased number of P-bodies has negligible effects on microRNA-mediated translation repression and nonsense mediated decay, further supporting the view that the function of proteins localized in P-bodies is independent of visible P-bodies.
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Affiliation(s)
- Ivan Novotny
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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20
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Tanackovic G, Ransijn A, Ayuso C, Harper S, Berson E, Rivolta C. A missense mutation in PRPF6 causes impairment of pre-mRNA splicing and autosomal-dominant retinitis pigmentosa. Am J Hum Genet 2011; 88:643-9. [PMID: 21549338 DOI: 10.1016/j.ajhg.2011.04.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 04/11/2011] [Accepted: 04/13/2011] [Indexed: 01/08/2023] Open
Abstract
Retinitis pigmentosa (RP) is an inherited form of retinal degeneration that leads to progressive visual-field constriction and blindness. Although the disease manifests only in the retina, mutations in ubiquitously expressed genes associated with the tri-snRNP complex of the spliceosome have been identified in patients with dominantly inherited RP. We screened for mutations in PRPF6 (NM_012469.3), a gene on chromosome 20q13.33 encoding an essential protein for tri-snRNP assembly and stability, in 188 unrelated patients with autosomal-dominant RP and identified a missense mutation, c.2185C>T (p.Arg729Trp). This change affected a residue that is conserved from humans to yeast and cosegregated with the disease in the family in which it was identified. Lymphoblasts derived from patients with this mutation showed abnormal localization of endogenous PRPF6 within the nucleus. Specifically, this protein accumulated in the Cajal bodies, indicating a possible impairment in the tri-snRNP assembly or recycling. Expression of GFP-tagged PRPF6 in HeLa cells showed that this phenomenon depended exclusively on the mutated form of the protein. Furthermore, analysis of endogenous transcripts in cells from patients revealed intron retention for pre-mRNA bearing specific splicing signals, according to the same pattern displayed by lymphoblasts with mutations in other PRPF genes. Our results identify PRPF6 as the sixth gene involved in pre-mRNA splicing and dominant RP, corroborating the hypothesis that deficiencies in the spliceosome play an important role in the molecular pathology of this disease.
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Abstract
There is increasing evidence to suggest that splicing decisions are largely made when the nascent RNA is still associated with chromatin. Here we demonstrate that activity of histone deacetylases (HDACs) influences splice site selection. Using splicing-sensitive microarrays, we identified ∼700 genes whose splicing was altered after HDAC inhibition. We provided evidence that HDAC inhibition induced histone H4 acetylation and increased RNA Polymerase II (Pol II) processivity along an alternatively spliced element. In addition, HDAC inhibition reduced co-transcriptional association of the splicing regulator SRp40 with the target fibronectin exon. We further showed that the depletion of HDAC1 had similar effect on fibronectin alternative splicing as global HDAC inhibition. Importantly, this effect was reversed upon expression of mouse HDAC1 but not a catalytically inactive mutant. These results provide a molecular insight into a complex modulation of splicing by HDACs and chromatin modifications.
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22
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Huranová M, Ivani I, Benda A, Poser I, Brody Y, Hof M, Shav-Tal Y, Neugebauer KM, Stanek D. The differential interaction of snRNPs with pre-mRNA reveals splicing kinetics in living cells. ACTA ACUST UNITED AC 2010; 191:75-86. [PMID: 20921136 PMCID: PMC2953428 DOI: 10.1083/jcb.201004030] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
GFP-tagged snRNP components reveal the dynamics and rate for spliceosome assembly in vivo. Precursor messenger RNA (pre-mRNA) splicing is catalyzed by the spliceosome, a large ribonucleoprotein (RNP) complex composed of five small nuclear RNP particles (snRNPs) and additional proteins. Using live cell imaging of GFP-tagged snRNP components expressed at endogenous levels, we examined how the spliceosome assembles in vivo. A comprehensive analysis of snRNP dynamics in the cell nucleus enabled us to determine snRNP diffusion throughout the nucleoplasm as well as the interaction rates of individual snRNPs with pre-mRNA. Core components of the spliceosome, U2 and U5 snRNPs, associated with pre-mRNA for 15–30 s, indicating that splicing is accomplished within this time period. Additionally, binding of U1 and U4/U6 snRNPs with pre-mRNA occurred within seconds, indicating that the interaction of individual snRNPs with pre-mRNA is distinct. These results are consistent with the predictions of the step-wise model of spliceosome assembly and provide an estimate on the rate of splicing in human cells.
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Affiliation(s)
- Martina Huranová
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, 142 20 Prague, Czech Republic
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23
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Linder B, Dill H, Hirmer A, Brocher J, Lee GP, Mathavan S, Bolz HJ, Winkler C, Laggerbauer B, Fischer U. Systemic splicing factor deficiency causes tissue-specific defects: a zebrafish model for retinitis pigmentosa. Hum Mol Genet 2010; 20:368-77. [PMID: 21051334 DOI: 10.1093/hmg/ddq473] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Retinitis pigmentosa (RP) is a common hereditary eye disease that causes blindness due to a progressive loss of photoreceptors in the retina. RP can be elicited by mutations that affect the tri-snRNP subunit of the pre-mRNA splicing machinery, but how defects in this essential macromolecular complex transform into a photoreceptor-specific phenotype is unknown. We have modeled the disease in zebrafish by silencing the RP-associated splicing factor Prpf31 and observed detrimental effects on visual function and photoreceptor morphology. Despite reducing the level of a constitutive splicing factor, no general defects in gene expression were found. Instead, retinal genes were selectively affected, providing the first in vivo link between mutations in splicing factors and the RP phenotype. Silencing of Prpf4, a splicing factor hitherto unrelated to RP, evoked the same defects in vision, photoreceptor morphology and retinal gene expression. Hence, various routes affecting the tri-snRNP can elicit tissue-specific gene expression defects and lead to the RP phenotype.
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Affiliation(s)
- Bastian Linder
- Department of Biochemistry, University of Würzburg, Würzburg, Germany
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24
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Mort M, Evani US, Krishnan VG, Kamati KK, Baenziger PH, Bagchi A, Peters BJ, Sathyesh R, Li B, Sun Y, Xue B, Shah NH, Kann MG, Cooper DN, Radivojac P, Mooney SD. In silico functional profiling of human disease-associated and polymorphic amino acid substitutions. Hum Mutat 2010; 31:335-46. [PMID: 20052762 DOI: 10.1002/humu.21192] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
An important challenge in translational bioinformatics is to understand how genetic variation gives rise to molecular changes at the protein level that can precipitate both monogenic and complex disease. To this end, we compiled datasets of human disease-associated amino acid substitutions (AAS) in the contexts of inherited monogenic disease, complex disease, functional polymorphisms with no known disease association, and somatic mutations in cancer, and compared them with respect to predicted functional sites in proteins. Using the sequence homology-based tool SIFT to estimate the proportion of deleterious AAS in each dataset, only complex disease AAS were found to be indistinguishable from neutral polymorphic AAS. Investigation of monogenic disease AAS predicted to be nondeleterious by SIFT were characterized by a significant enrichment for inherited AAS within solvent accessible residues, regions of intrinsic protein disorder, and an association with the loss or gain of various posttranslational modifications. Sites of structural and/or functional interest were therefore surmised to constitute useful additional features with which to identify the molecular disruptions caused by deleterious AAS. A range of bioinformatic tools, designed to predict structural and functional sites in protein sequences, were then employed to demonstrate that intrinsic biases exist in terms of the distribution of different types of human AAS with respect to specific structural, functional and pathological features. Our Web tool, designed to potentiate the functional profiling of novel AAS, has been made available at http://profile.mutdb.org/.
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Affiliation(s)
- Matthew Mort
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
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25
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Audo I, Bujakowska K, Mohand-Saïd S, Lancelot ME, Moskova-Doumanova V, Waseem NH, Antonio A, Sahel JA, Bhattacharya SS, Zeitz C. Prevalence and novelty of PRPF31 mutations in French autosomal dominant rod-cone dystrophy patients and a review of published reports. BMC MEDICAL GENETICS 2010; 11:145. [PMID: 20939871 PMCID: PMC2984399 DOI: 10.1186/1471-2350-11-145] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 10/12/2010] [Indexed: 12/01/2022]
Abstract
Background Rod-cone dystrophies are heterogeneous group of inherited retinal disorders both clinically and genetically characterized by photoreceptor degeneration. The mode of inheritance can be autosomal dominant, autosomal recessive or X-linked. The purpose of this study was to identify mutations in one of the genes, PRPF31, in French patients with autosomal dominant RP, to perform genotype-phenotype correlations of those patients, to determine the prevalence of PRPF31 mutations in this cohort and to review previously identified PRPF31 mutations from other cohorts. Methods Detailed phenotypic characterization was performed including precise family history, best corrected visual acuity using the ETDRS chart, slit lamp examination, kinetic and static perimetry, full field and multifocal ERG, fundus autofluorescence imaging and optic coherence tomography. For genetic diagnosis, genomic DNA of ninety families was isolated by standard methods. The coding exons and flanking intronic regions of PRPF31 were PCR amplified, purified and sequenced in the index patient. Results We showed for the first time that 6.7% cases of a French adRP cohort have a PRPF31 mutation. We identified in total six mutations, which were all novel and not detected in ethnically matched controls. The mutation spectrum from our cohort comprises frameshift and splice site mutations. Co-segregation analysis in available family members revealed that each index patient and all affected family members showed a heterozygous mutation. In five families incomplete penetrance was observed. Most patients showed classical signs of RP with relatively preserved central vision and visual field. Conclusion Our studies extended the mutation spectrum of PRPF31 and as previously reported in other populations, it is a major cause of adRP in France.
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