1
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Zhang Z, Kumar V, Dybkov O, Will CL, Zhong J, Ludwig SEJ, Urlaub H, Kastner B, Stark H, Lührmann R. Structural insights into the cross-exon to cross-intron spliceosome switch. Nature 2024; 630:1012-1019. [PMID: 38778104 PMCID: PMC11208138 DOI: 10.1038/s41586-024-07458-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 04/23/2024] [Indexed: 05/25/2024]
Abstract
Early spliceosome assembly can occur through an intron-defined pathway, whereby U1 and U2 small nuclear ribonucleoprotein particles (snRNPs) assemble across the intron1. Alternatively, it can occur through an exon-defined pathway2-5, whereby U2 binds the branch site located upstream of the defined exon and U1 snRNP interacts with the 5' splice site located directly downstream of it. The U4/U6.U5 tri-snRNP subsequently binds to produce a cross-intron (CI) or cross-exon (CE) pre-B complex, which is then converted to the spliceosomal B complex6,7. Exon definition promotes the splicing of upstream introns2,8,9 and plays a key part in alternative splicing regulation10-16. However, the three-dimensional structure of exon-defined spliceosomal complexes and the molecular mechanism of the conversion from a CE-organized to a CI-organized spliceosome, a pre-requisite for splicing catalysis, remain poorly understood. Here cryo-electron microscopy analyses of human CE pre-B complex and B-like complexes reveal extensive structural similarities with their CI counterparts. The results indicate that the CE and CI spliceosome assembly pathways converge already at the pre-B stage. Add-back experiments using purified CE pre-B complexes, coupled with cryo-electron microscopy, elucidate the order of the extensive remodelling events that accompany the formation of B complexes and B-like complexes. The molecular triggers and roles of B-specific proteins in these rearrangements are also identified. We show that CE pre-B complexes can productively bind in trans to a U1 snRNP-bound 5' splice site. Together, our studies provide new mechanistic insights into the CE to CI switch during spliceosome assembly and its effect on pre-mRNA splice site pairing at this stage.
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Affiliation(s)
- Zhenwei Zhang
- Department of Structural Dynamics, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- State Key Laboratory of Biotherapy and Department of Rheumatology and Immunology, West China Hospital, Sichuan University, Chengdu, China
| | - Vinay Kumar
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Olexandr Dybkov
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- Bioanalytical Mass Spectrometry, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Cindy L Will
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Jiayun Zhong
- State Key Laboratory of Biotherapy and Department of Rheumatology and Immunology, West China Hospital, Sichuan University, Chengdu, China
| | - Sebastian E J Ludwig
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- Vincerx Pharma, Monheim am Rhein, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Berthold Kastner
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Holger Stark
- Department of Structural Dynamics, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany.
| | - Reinhard Lührmann
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany.
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2
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Tyagi R, Rosa BA, Swain A, Artyomov MN, Jasmer DP, Mitreva M. Intestinal cell diversity and treatment responses in a parasitic nematode at single cell resolution. BMC Genomics 2024; 25:341. [PMID: 38575858 PMCID: PMC10996262 DOI: 10.1186/s12864-024-10203-7] [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: 12/08/2023] [Accepted: 03/08/2024] [Indexed: 04/06/2024] Open
Abstract
BACKGROUND Parasitic nematodes, significant pathogens for humans, animals, and plants, depend on diverse organ systems for intra-host survival. Understanding the cellular diversity and molecular variations underlying these functions holds promise for developing novel therapeutics, with specific emphasis on the neuromuscular system's functional diversity. The nematode intestine, crucial for anthelmintic therapies, exhibits diverse cellular phenotypes, and unraveling this diversity at the single-cell level is essential for advancing knowledge in anthelmintic research across various organ systems. RESULTS Here, using novel single-cell transcriptomics datasets, we delineate cellular diversity within the intestine of adult female Ascaris suum, a parasitic nematode species that infects animals and people. Gene transcripts expressed in individual nuclei of untreated intestinal cells resolved three phenotypic clusters, while lower stringency resolved additional subclusters and more potential diversity. Clusters 1 and 3 phenotypes displayed variable congruence with scRNA phenotypes of C. elegans intestinal cells, whereas the A. suum cluster 2 phenotype was markedly unique. Distinct functional pathway enrichment characterized each A. suum intestinal cell cluster. Cluster 2 was distinctly enriched for Clade III-associated genes, suggesting it evolved within clade III nematodes. Clusters also demonstrated differential transcriptional responsiveness to nematode intestinal toxic treatments, with Cluster 2 displaying the least responses to short-term intra-pseudocoelomic nematode intestinal toxin treatments. CONCLUSIONS This investigation presents advances in knowledge related to biological differences among major cell populations of adult A. suum intestinal cells. For the first time, diverse nematode intestinal cell populations were characterized, and associated biological markers of these cells were identified to support tracking of constituent cells under experimental conditions. These advances will promote better understanding of this and other parasitic nematodes of global importance, and will help to guide future anthelmintic treatments.
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Affiliation(s)
- Rahul Tyagi
- Division of Infectious Diseases, Department of Internal Medicine, Washington University School of Medicine, 63110, St. Louis, MO, USA
| | - Bruce A Rosa
- Division of Infectious Diseases, Department of Internal Medicine, Washington University School of Medicine, 63110, St. Louis, MO, USA
| | - Amanda Swain
- Department of Pathology and Immunology, Washington University School of Medicine, 63110, Saint Louis, MO, USA
| | - Maxim N Artyomov
- Department of Pathology and Immunology, Washington University School of Medicine, 63110, Saint Louis, MO, USA
| | - Douglas P Jasmer
- Department of Veterinary Microbiology and Pathology, Washington State University, 99164, Pullman, WA, USA.
| | - Makedonka Mitreva
- Division of Infectious Diseases, Department of Internal Medicine, Washington University School of Medicine, 63110, St. Louis, MO, USA.
- Department of Genetics, Washington University School of Medicine, 63110, St. Louis, MO, USA.
- McDonnell Genome Institute, Washington University School of Medicine, 63110, St Louis, MO, USA.
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3
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Lugano DI, Barrett LN, Chaput D, Park MA, Westerheide SD. CCAR-1 works together with the U2AF large subunit UAF-1 to regulate alternative splicing. RNA Biol 2024; 21:1-11. [PMID: 38126797 PMCID: PMC10761121 DOI: 10.1080/15476286.2023.2289707] [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] [Accepted: 11/17/2023] [Indexed: 12/23/2023] Open
Abstract
The Cell Division Cycle and Apoptosis Regulator (CCAR) protein family members have recently emerged as regulators of alternative splicing and transcription, as well as having other key physiological functions. For example, mammalian CCAR2/DBC1 forms a complex with the zinc factor protein ZNF326 to integrate alternative splicing with RNA polymerase II transcriptional elongation in AT-rich regions of the DNA. Additionally, Caenorhabditis elegans CCAR-1, a homolog to mammalian CCAR2, facilitates the alternative splicing of the perlecan unc-52 gene. However, much about the CCAR family's role in alternative splicing is unknown. Here, we have examined the role of CCAR-1 in genome-wide alternative splicing in Caenorhabditis elegans and have identified new alternative splicing targets of CCAR-1 using RNA sequencing. Also, we found that CCAR-1 interacts with the spliceosome factors UAF-1 and UAF-2 using mass spectrometry, and that knockdown of ccar-1 affects alternative splicing patterns, motility, and proteostasis of UAF-1 mutant worms. Collectively, we demonstrate the role of CCAR-1 in regulating global alternative splicing in C. elegans and in conjunction with UAF-1.
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Affiliation(s)
- Doreen I. Lugano
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Lindsey N. Barrett
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Dale Chaput
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Margaret A. Park
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Sandy D. Westerheide
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL, USA
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4
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Kwon HC, Bae Y, Lee SJV. The Role of mRNA Quality Control in the Aging of Caenorhabditis elegans. Mol Cells 2023; 46:664-671. [PMID: 37968980 PMCID: PMC10654458 DOI: 10.14348/molcells.2023.0103] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/17/2023] [Accepted: 09/02/2023] [Indexed: 11/17/2023] Open
Abstract
The proper maintenance of mRNA quality that is regulated by diverse surveillance pathways is essential for cellular homeostasis and is highly conserved among eukaryotes. Here, we review findings regarding the role of mRNA quality control in the aging and longevity of Caenorhabditis elegans, an outstanding model for aging research. We discuss the recently discovered functions of the proper regulation of nonsense-mediated mRNA decay, ribosome-associated quality control, and mRNA splicing in the aging of C. elegans. We describe how mRNA quality control contributes to longevity conferred by various regimens, including inhibition of insulin/insulin-like growth factor 1 (IGF-1) signaling, dietary restriction, and reduced mechanistic target of rapamycin signaling. This review provides valuable information regarding the relationship between the mRNA quality control and aging in C. elegans, which may lead to insights into healthy longevity in complex organisms, including humans.
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Affiliation(s)
- Hyunwoo C. Kwon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Yunkyu Bae
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Seung-Jae V. Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
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5
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Sarafidou T, Galliopoulou E, Apostolopoulou D, Fragkiadakis GA, Moschonas NK. Reconstruction of a Comprehensive Interactome and Experimental Data Analysis of FRA10AC1 May Provide Insights into Its Biological Role in Health and Disease. Genes (Basel) 2023; 14:genes14030568. [PMID: 36980839 PMCID: PMC10048706 DOI: 10.3390/genes14030568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/14/2023] [Accepted: 02/21/2023] [Indexed: 03/03/2023] Open
Abstract
FRA10AC1, the causative gene for the manifestation of the FRA10A fragile site, encodes a well-conserved nuclear protein characterized as a non-core spliceosomal component. Pre-mRNA splicing perturbations have been linked with neurodevelopmental diseases. FRA10AC1 variants have been, recently, causally linked with severe neuropathological and growth retardation phenotypes. To further elucidate the participation of FRA10AC1 in spliceosomal multiprotein complexes and its involvement in neurological phenotypes related to splicing, we exploited protein–protein interaction experimental data and explored network information and information deduced from transcriptomics. We confirmed the direct interaction of FRA10AC1with ESS2, a non-core spliceosomal protein, mapped their interacting domains, and documented their tissue co-localization and physical interaction at the level of intracellular protein stoichiometries. Although FRA10AC1 and SF3B2, a major core spliceosomal protein, were shown to interact under in vitro conditions, the endogenous proteins failed to co-immunoprecipitate. A reconstruction of a comprehensive, strictly binary, protein–protein interaction network of FRA10AC1 revealed dense interconnectivity with many disease-associated spliceosomal components and several non-spliceosomal regulatory proteins. The topological neighborhood of FRA10AC1 depicts an interactome associated with multiple severe monogenic and multifactorial neurodevelopmental diseases mainly referring to spliceosomopathies. Our results suggest that FRA10AC1 involvement in pre-mRNA processing might be strengthened by interconnecting splicing with transcription and mRNA export, and they propose the broader role(s) of FRA10AC1 in cell pathophysiology.
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Affiliation(s)
- Theologia Sarafidou
- Department of Biochemistry and Biotechnology, University of Thessaly, Viopolis, 41500 Larissa, Greece
- Correspondence: (T.S.); (N.K.M.)
| | - Eleni Galliopoulou
- Department of Biochemistry and Biotechnology, University of Thessaly, Viopolis, 41500 Larissa, Greece
| | | | - Georgios A. Fragkiadakis
- Department of Nutrition and Dietetics Sciences, Hellenic Mediterranean University, Tripitos, 72300 Siteia, Greece
| | - Nicholas K. Moschonas
- School of Medicine, University of Patras, 26500 Patras, Greece
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas (FORTH/ICE-HT), 26504 Patras, Greece
- Correspondence: (T.S.); (N.K.M.)
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6
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Kolathur KK, Sharma P, Kadam NY, Shahi N, Nishitha A, Babu K, Mishra SK. The ubiquitin-like protein Hub1/UBL-5 functions in pre-mRNA splicing in Caenorhabditis elegans. FEBS Lett 2023; 597:448-457. [PMID: 36480405 PMCID: PMC7615767 DOI: 10.1002/1873-3468.14555] [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: 03/24/2022] [Revised: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022]
Abstract
The ubiquitin-like protein Hub1/UBL-5 associates with proteins non-covalently. Hub1 promotes alternative splicing and splicing of precursor mRNAs with weak introns in yeast and mammalian cells; however, its splicing function has remained elusive in multicellular organisms. Here, we demonstrate the splicing function of Hub1/UBL-5 in the free-living nematode Caenorhabditis elegans. Hub1/UBL-5 binds to the HIND-containing splicing factors Snu66/SART-1 and PRP-38 and associates with other spliceosomal proteins. C. elegans hub1/ubl-5 mutants die at the Larval 3 stage and show splicing defects for selected targets, similar to the mutants in yeast and mammalian cells. UBL-5 complemented growth and splicing defects in Schizosaccharomyces pombe hub1 mutants, confirming its functional conservation. Thus, UBL-5 is important for C. elegans development and plays a conserved pre-mRNA splicing function.
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Affiliation(s)
- Kiran Kumar Kolathur
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India
- Department of Pharmaceutical Biotechnology, Manipal College of Pharmaceutical Sciences (MCOPS), Manipal Academy of Higher Education (MAHE), India
| | - Pallavi Sharma
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Nagesh Y Kadam
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India
| | - Navneet Shahi
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Ane Nishitha
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India
| | - Kavita Babu
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Shravan Kumar Mishra
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India
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7
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Vester K, Preußner M, Holton N, Feng S, Schultz C, Heyd F, Wahl MC. Recruitment of a splicing factor to the nuclear lamina for its inactivation. Commun Biol 2022; 5:736. [PMID: 35869234 PMCID: PMC9307855 DOI: 10.1038/s42003-022-03689-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 07/08/2022] [Indexed: 11/10/2022] Open
Abstract
Precursor messenger RNA splicing is a highly regulated process, mediated by a complex RNA-protein machinery, the spliceosome, that encompasses several hundred proteins and five small nuclear RNAs in humans. Emerging evidence suggests that the spatial organization of splicing factors and their spatio-temporal dynamics participate in the regulation of splicing. So far, methods to manipulate the spatial distribution of splicing factors in a temporally defined manner in living cells are missing. Here, we describe such an approach that takes advantage of a reversible chemical dimerizer, and outline the requirements for efficient, reversible re-localization of splicing factors to selected sub-nuclear compartments. In a proof-of-principle study, the partial re-localization of the PRPF38A protein to the nuclear lamina in HEK293T cells induced a moderate increase in intron retention. Our approach allows fast and reversible re-localization of splicing factors, has few side effects and can be applied to many splicing factors by fusion of a protein tag through genome engineering. Apart from the systematic analysis of the spatio-temporal aspects of splicing regulation, the approach has a large potential for the fast induction and reversal of splicing switches and can reveal mechanisms of splicing regulation in native nuclear environments. Through the use of a reversible chemical dimerizer, the splicing factor PRPF38A is re-localized to the nuclear lamina, paving the way for a systematic analysis of spatio-temporal splicing regulation.
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8
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Mohammadi A, Sorensen GL, Pilecki B. MFAP4-Mediated Effects in Elastic Fiber Homeostasis, Integrin Signaling and Cancer, and Its Role in Teleost Fish. Cells 2022; 11:cells11132115. [PMID: 35805199 PMCID: PMC9265350 DOI: 10.3390/cells11132115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/29/2022] [Accepted: 07/01/2022] [Indexed: 11/16/2022] Open
Abstract
Microfibrillar-associated protein 4 (MFAP4) is an extracellular matrix (ECM) protein belonging to the fibrinogen-related domain superfamily. MFAP4 is highly expressed in elastin-rich tissues such as lung, blood vessels and skin. MFAP4 is involved in organization of the ECM, regulating proper elastic fiber assembly. On the other hand, during pathology MFAP4 actively contributes to disease development and progression due to its interactions with RGD-dependent integrin receptors. Both tissue expression and circulating MFAP4 levels are associated with various disorders, including liver fibrosis and cancer. In other experimental models, such as teleost fish, MFAP4 appears to participate in host defense as a macrophage-specific innate immune molecule. The aim of this review is to summarize the accumulating evidence that indicates the importance of MFAP4 in homeostasis as well as pathological conditions, discuss its known biological functions with special focus on elastic fiber assembly, integrin signaling and cancer, as well as describe the reported functions of non-mammalian MFAP4 in fish. Overall, our work provides a comprehensive overview on the role of MFAP4 in health and disease.
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9
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Kamp JA, Lemmens BBLG, Romeijn RJ, González-Prieto R, Olsen J, Vertegaal ACO, van Schendel R, Tijsterman M. THO complex deficiency impairs DNA double-strand break repair via the RNA surveillance kinase SMG-1. Nucleic Acids Res 2022; 50:6235-6250. [PMID: 35670662 PMCID: PMC9226523 DOI: 10.1093/nar/gkac472] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 05/11/2022] [Accepted: 06/02/2022] [Indexed: 12/25/2022] Open
Abstract
The integrity and proper expression of genomes are safeguarded by DNA and RNA surveillance pathways. While many RNA surveillance factors have additional functions in the nucleus, little is known about the incidence and physiological impact of converging RNA and DNA signals. Here, using genetic screens and genome-wide analyses, we identified unforeseen SMG-1-dependent crosstalk between RNA surveillance and DNA repair in living animals. Defects in RNA processing, due to viable THO complex or PNN-1 mutations, induce a shift in DNA repair in dividing and non-dividing tissues. Loss of SMG-1, an ATM/ATR-like kinase central to RNA surveillance by nonsense-mediated decay (NMD), restores DNA repair and radio-resistance in THO-deficient animals. Mechanistically, we find SMG-1 and its downstream target SMG-2/UPF1, but not NMD per se, to suppress DNA repair by non-homologous end-joining in favour of single strand annealing. We postulate that moonlighting proteins create short-circuits in vivo, allowing aberrant RNA to redirect DNA repair.
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Affiliation(s)
| | | | - Ron J Romeijn
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - Román González-Prieto
- Department of Cell & Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands
| | - Jesper V Olsen
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Alfred C O Vertegaal
- Department of Cell & Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands
| | - Robin van Schendel
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
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10
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Kanaan R, Medlej-Hashim M, Jounblat R, Pilecki B, Sorensen GL. Microfibrillar-associated protein 4 in health and disease. Matrix Biol 2022; 111:1-25. [DOI: 10.1016/j.matbio.2022.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 05/04/2022] [Accepted: 05/24/2022] [Indexed: 10/18/2022]
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11
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Li Y, Li T, He X, Zhu Y, Feng Q, Yang X, Zhou X, Li G, Ji Y, Zhao J, Zhao Z, Pu M, Zhou S, Zhang J, Huang Y, Fan J, Wang W. Blocking Osa-miR1871 enhances rice resistance against Magnaporthe oryzae and yield. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:646-659. [PMID: 34726307 PMCID: PMC8989506 DOI: 10.1111/pbi.13743] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 07/31/2021] [Accepted: 10/24/2021] [Indexed: 05/04/2023]
Abstract
MicroRNAs (miRNAs) play vital roles in plant development and defence responses against various stresses. Here, we show that blocking miR1871 improves rice resistance against Magnaporthe oryzae and enhances grain yield simultaneously. The transgenic lines overexpressing miR1871 (OX1871) exhibit compromised resistance, suppressed defence responses and reduced panicle number resulting in slightly decreased yield. In contrast, the transgenic lines blocking miR1871 (MIM1871) show improved resistance, enhanced defence responses and significantly increased panicle number leading to enhanced yield per plant. The RNA-seq assay and defence response assays reveal that blocking miR1871 resulted in the enhancement of PAMP-triggered immunity (PTI). Intriguingly, miR1871 suppresses the expression of LOC_Os06g22850, which encodes a microfibrillar-associated protein (MFAP1) locating nearby the cell wall and positively regulating PTI responses. The mutants of MFAP1 resemble the phenotype of OX1871. Conversely, the transgenic lines overexpressing MFAP1 (OXMFAP1) or overexpressing both MFAP1 and miR1871 (OXMFAP1/OX1871) resemble the resistance of MIM1871. The time-course experiment data reveal that the expression of miR1871 and MFAP1 in rice leaves, panicles and basal internode is dynamic during the whole growth period to manipulate the resistance and yield traits. Our results suggest that miR1871 regulates rice yield and immunity via MFAP1, and the miR8171-MFAP1 module could be used in rice breeding to improve both immunity and yield.
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Affiliation(s)
- Yan Li
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Ting‐Ting Li
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Xiao‐Rong He
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Yong Zhu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Qin Feng
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Xue‐Mei Yang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Xin‐Hui Zhou
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Guo‐Bang Li
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Yun‐Peng Ji
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Jing‐Hao Zhao
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Zhi‐Xue Zhao
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Mei Pu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Shi‐Xin Zhou
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Ji‐Wei Zhang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Yan‐Yan Huang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Jing Fan
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
| | - Wen‐Ming Wang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural UniversityChengduChina
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12
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Mei C, Song PY, Zhang W, Zhou HH, Li X, Liu ZQ. Aberrant RNA Splicing Events Driven by Mutations of RNA-Binding Proteins as Indicators for Skin Cutaneous Melanoma Prognosis. Front Oncol 2020; 10:568469. [PMID: 33178596 PMCID: PMC7593665 DOI: 10.3389/fonc.2020.568469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/14/2020] [Indexed: 12/29/2022] Open
Abstract
The worldwide incidence of skin cutaneous melanoma (SKCM) is increasing at a more rapid rate than other tumors. Aberrant alternative splicing (AS) is found to be common in cancer; however, how this process contributes to cancer prognosis still remains largely unknown. Mutations in RNA-binding proteins (RBPs) may trigger great changes in the splicing process. In this study, we comprehensively analyzed DNA and RNA sequencing data and clinical information of SKCM patients, together with widespread changes in splicing patterns induced by RBP mutations. We screened mRNA expression-related and prognosis-related mutations in RBPs and investigated the potential affections of RBP mutations on splicing patterns. Mutations in 853 RBPs were demonstrated to be correlated with splicing aberrations (p < 0.01). Functional enrichment analysis revealed that these alternative splicing events (ASEs) may participate in tumor progress by regulating the modification process, cell-cycle checkpoint, metabolic pathways, MAPK signaling, PI3K-Akt signaling, and other important pathways in cancer. We also constructed a prediction model based on overall survival-related AS events (OS-ASEs) affected by RBP mutations, which exhibited a good predict efficiency with the area under the curve of 0.989. Our work highlights the importance of RBP mutations in splicing alterations and provides effective biomarkers for prediction of prognosis of SKCM.
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Affiliation(s)
- Chao Mei
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Key Laboratory of Biological Nanotechnology of National Health Commission, and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Engineering Research Center for Applied Technology of Pharmacogenomics of Ministry of Education, Institute of Clinical Pharmacology, Central South University, Changsha, China
| | - Pei-Yuan Song
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Key Laboratory of Biological Nanotechnology of National Health Commission, and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Engineering Research Center for Applied Technology of Pharmacogenomics of Ministry of Education, Institute of Clinical Pharmacology, Central South University, Changsha, China
| | - Wei Zhang
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Key Laboratory of Biological Nanotechnology of National Health Commission, and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Engineering Research Center for Applied Technology of Pharmacogenomics of Ministry of Education, Institute of Clinical Pharmacology, Central South University, Changsha, China
| | - Hong-Hao Zhou
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Key Laboratory of Biological Nanotechnology of National Health Commission, and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Engineering Research Center for Applied Technology of Pharmacogenomics of Ministry of Education, Institute of Clinical Pharmacology, Central South University, Changsha, China
| | - Xi Li
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Key Laboratory of Biological Nanotechnology of National Health Commission, and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Engineering Research Center for Applied Technology of Pharmacogenomics of Ministry of Education, Institute of Clinical Pharmacology, Central South University, Changsha, China
| | - Zhao-Qian Liu
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Key Laboratory of Biological Nanotechnology of National Health Commission, and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Engineering Research Center for Applied Technology of Pharmacogenomics of Ministry of Education, Institute of Clinical Pharmacology, Central South University, Changsha, China
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13
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Depletion of the MFAP1/SPP381 Splicing Factor Causes R-Loop-Independent Genome Instability. Cell Rep 2020; 28:1551-1563.e7. [PMID: 31390568 PMCID: PMC6693559 DOI: 10.1016/j.celrep.2019.07.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 03/18/2019] [Accepted: 07/01/2019] [Indexed: 01/19/2023] Open
Abstract
THO/TREX is a conserved complex with a role in messenger ribonucleoprotein biogenesis that links gene expression and genome instability. Here, we show that human THO interacts with MFAP1 (microfibrillar-associated protein 1), a spliceosome-associated factor. Interestingly, MFAP1 depletion impairs cell proliferation and genome integrity, increasing γH2AX foci and DNA breaks. This phenotype is not dependent on either transcription or RNA-DNA hybrids. Mutations in the yeast orthologous gene SPP381 cause similar transcription-independent genome instability, supporting a conserved role. MFAP1 depletion has a wide effect on splicing and gene expression in human cells, determined by transcriptome analyses. MFAP1 depletion affects a number of DNA damage response (DDR) genes, which supports an indirect role of MFAP1 on genome integrity. Our work defines a functional interaction between THO and RNA processing and argues that splicing factors may contribute to genome integrity indirectly by regulating the expression of DDR genes rather than by a direct role.
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14
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Arribere JA, Kuroyanagi H, Hundley HA. mRNA Editing, Processing and Quality Control in Caenorhabditis elegans. Genetics 2020; 215:531-568. [PMID: 32632025 PMCID: PMC7337075 DOI: 10.1534/genetics.119.301807] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 05/03/2020] [Indexed: 02/06/2023] Open
Abstract
While DNA serves as the blueprint of life, the distinct functions of each cell are determined by the dynamic expression of genes from the static genome. The amount and specific sequences of RNAs expressed in a given cell involves a number of regulated processes including RNA synthesis (transcription), processing, splicing, modification, polyadenylation, stability, translation, and degradation. As errors during mRNA production can create gene products that are deleterious to the organism, quality control mechanisms exist to survey and remove errors in mRNA expression and processing. Here, we will provide an overview of mRNA processing and quality control mechanisms that occur in Caenorhabditis elegans, with a focus on those that occur on protein-coding genes after transcription initiation. In addition, we will describe the genetic and technical approaches that have allowed studies in C. elegans to reveal important mechanistic insight into these processes.
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Affiliation(s)
| | - Hidehito Kuroyanagi
- Laboratory of Gene Expression, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 113-8510, Japan, and
| | - Heather A Hundley
- Medical Sciences Program, Indiana University School of Medicine-Bloomington, Indiana 47405
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15
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Zhou C, Gao X, Hu S, Gan W, Xu J, Ma YC, Ma L. RBM-5 modulates U2AF large subunit-dependent alternative splicing in C. elegans. RNA Biol 2018; 15:1295-1308. [PMID: 30295127 PMCID: PMC6284560 DOI: 10.1080/15476286.2018.1526540] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/23/2018] [Accepted: 09/11/2018] [Indexed: 01/06/2023] Open
Abstract
A key step in pre-mRNA splicing is the recognition of 3' splicing sites by the U2AF large and small subunits, a process regulated by numerous trans-acting splicing factors. How these trans-acting factors interact with U2AF in vivo is unclear. From a screen for suppressors of the temperature-sensitive (ts) lethality of the C. elegans U2AF large subunit gene uaf-1(n4588) mutants, we identified mutations in the RNA binding motif gene rbm-5, a homolog of the tumor suppressor gene RBM5. rbm-5 mutations can suppress uaf-1(n4588) ts-lethality by loss of function and neuronal expression of rbm-5 was sufficient to rescue the suppression. Transcriptome analyses indicate that uaf-1(n4588) affected the expression of numerous genes and rbm-5 mutations can partially reverse the abnormal gene expression to levels similar to that of wild type. Though rbm-5 mutations did not obviously affect alternative splicing per se, they can suppress or enhance, in a gene-specific manner, the altered splicing of genes in uaf-1(n4588) mutants. Specifically, the recognition of a weak 3' splice site was more susceptible to the effect of rbm-5. Our findings provide novel in vivo evidence that RBM-5 can modulate UAF-1-dependent RNA splicing and suggest that RBM5 might interact with U2AF large subunit to affect tumor formation.
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Affiliation(s)
- Chuanman Zhou
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xiaoyang Gao
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Surong Hu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Wenjing Gan
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Jing Xu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Yongchao C. Ma
- Departments of Pediatrics, Neurology and Physiology, Northwestern University Feinberg School of Medicine, Anne & Robert H. Lurie Children’s Hospital of Chicago, Chicago, Illinois, USA
| | - Long Ma
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
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16
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Rode S, Ohm H, Zipfel J, Rumpf S. The spliceosome-associated protein Mfap1 binds to VCP in Drosophila. PLoS One 2017; 12:e0183733. [PMID: 28837687 PMCID: PMC5570293 DOI: 10.1371/journal.pone.0183733] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 08/09/2017] [Indexed: 12/14/2022] Open
Abstract
Posttranscriptional regulation of gene expression contributes to many developmental transitions. Previously, we found that the AAA chaperone Valosin-Containing Protein (VCP) regulates ecdysone-dependent dendrite pruning of Drosophila class IV dendritic arborization (c4da) neurons via an effect on RNA metabolism. In a search for RNA binding proteins associated with VCP, we identified the spliceosome-associated protein Mfap1, a component of the tri-snRNP complex. Mfap1 is a nucleolar protein in neurons and its levels are regulated by VCP. Mfap1 binds to VCP and TDP-43, a disease-associated RNA-binding protein. via distinct regions in its N- and C-terminal halfs. Similar to vcp mutations, Mfap1 overexpression causes c4da neuron dendrite pruning defects and mislocalization of TDP-43 in these cells, but genetic analyses show that Mfap1 is not a crucial VCP target during dendrite pruning. Finally, rescue experiments with a lethal mfap1 mutant show that the VCP binding region is not essential for Mfap1 function, but may act to increase its stability or activity.
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Affiliation(s)
- Sandra Rode
- Institute for Neurobiology, University of Münster, Badestrasse 9, Münster, Germany
| | - Henrike Ohm
- Institute for Neurobiology, University of Münster, Badestrasse 9, Münster, Germany
| | - Jaqueline Zipfel
- Institute for Neurobiology, University of Münster, Badestrasse 9, Münster, Germany
| | - Sebastian Rumpf
- Institute for Neurobiology, University of Münster, Badestrasse 9, Münster, Germany
- * E-mail:
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17
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Ulrich AKC, Wahl MC. Human MFAP1 is a cryptic ortholog of the Saccharomyces cerevisiae Spp381 splicing factor. BMC Evol Biol 2017; 17:91. [PMID: 28335716 PMCID: PMC5364666 DOI: 10.1186/s12862-017-0923-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 02/23/2017] [Indexed: 01/14/2023] Open
Abstract
Background Pre-mRNA splicing involves the stepwise assembly of a pre-catalytic spliceosome, followed by its catalytic activation, splicing catalysis and disassembly. Formation of the pre-catalytic spliceosomal B complex involves the incorporation of the U4/U6.U5 tri-snRNP and of a group of non-snRNP B-specific proteins. While in Saccharomyces cerevisiae the Prp38 and Snu23 proteins are recruited as components of the tri-snRNP, metazoan orthologs of Prp38 and Snu23 associate independently of the tri-snRNP as members of the B-specific proteins. The human spliceosome contains about 80 proteins that lack obvious orthologs in yeast, including most of the B-specific proteins apart from Prp38 and Snu23. Conversely, the tri-snRNP protein Spp381 is one of only five S. cerevisiae splicing factors without a known human ortholog. Results Using InParanoid, a state-of-the-art method for ortholog inference between pairs of species, and systematic BLAST searches we identified the human B-specific protein MFAP1 as a putative ortholog of the S. cerevisiae tri-snRNP protein Spp381. Bioinformatics revealed that MFAP1 and Spp381 share characteristic structural features, including intrinsic disorder, an elongated shape, solvent exposure of most residues and a trend to adopt α-helical structures. In vitro binding studies showed that human MFAP1 and yeast Spp381 bind their respective Prp38 proteins via equivalent interfaces and that they cross-interact with the Prp38 proteins of the respective other species. Furthermore, MFAP1 and Spp381 both form higher-order complexes that additionally include Snu23, suggesting that they are parts of equivalent spliceosomal sub-complexes. Finally, similar to yeast Spp381, human MFAP1 partially rescued a growth defect of the temperature-sensitive mutant yeast strain prp38-1. Conclusions Human B-specific protein MFAP1 structurally and functionally resembles the yeast tri-snRNP-specific protein Spp381 and thus qualifies as its so far missing ortholog. Our study indicates that the yeast Snu23-Prp38-Spp381 triple complex was evolutionarily reprogrammed from a tri-snRNP-specific module in yeast to the B-specific Snu23-Prp38-MFAP1 module in metazoa, affording higher flexibility in spliceosome assembly and thus, presumably, in splicing regulation. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0923-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexander K C Ulrich
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustr. 6, D-14195, Berlin, Germany.
| | - Markus C Wahl
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustr. 6, D-14195, Berlin, Germany. .,Helmholtz-Zentrum Berlin für Materialien und Energie, Macromolecular Crystallography, Albert-Einstein-Straße 15, D-12489, Berlin, Germany.
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18
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Ulrich AKC, Seeger M, Schütze T, Bartlick N, Wahl MC. Scaffolding in the Spliceosome via Single α Helices. Structure 2016; 24:1972-1983. [PMID: 27773687 DOI: 10.1016/j.str.2016.09.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/08/2016] [Accepted: 09/28/2016] [Indexed: 12/16/2022]
Abstract
The spliceosomal B complex-specific protein Prp38 forms a complex with the intrinsically unstructured proteins MFAP1 and Snu23. Our binding and crystal structure analyses show that MFAP1 and Snu23 contact Prp38 via ER/K motif-stabilized single α helices, which have previously been recognized only as rigid connectors or force springs between protein domains. A variant of the Prp38-binding single α helix of MFAP1, in which ER/K motifs not involved in Prp38 binding were mutated, was less α-helical in isolation and showed a reduced Prp38 affinity, with opposing tendencies in interaction enthalpy and entropy. Our results indicate that the strengths of single α helix-based interactions can be tuned by the degree of helix stabilization in the unbound state. MFAP1, Snu23, and several other spliceosomal proteins contain multiple regions that likely form single α helices via which they might tether several binding partners and act as intermittent scaffolds that facilitate remodeling steps during assembly of an active spliceosome.
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Affiliation(s)
- Alexander K C Ulrich
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Martin Seeger
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Tonio Schütze
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Natascha Bartlick
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
| | - Markus C Wahl
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany; Helmholtz-Zentrum Berlin für Materialien und Energie, Macromolecular Crystallography, Albert-Einstein-Straße 15, 12489 Berlin, Germany.
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19
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Ulrich A, Schulz J, Kamprad A, Schütze T, Wahl M. Structural Basis for the Functional Coupling of the Alternative Splicing Factors Smu1 and RED. Structure 2016; 24:762-773. [DOI: 10.1016/j.str.2016.03.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 02/22/2016] [Accepted: 03/08/2016] [Indexed: 12/25/2022]
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20
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Gao X, Teng Y, Luo J, Huang L, Li M, Zhang Z, Ma YC, Ma L. The survival motor neuron gene smn-1 interacts with the U2AF large subunit gene uaf-1 to regulate Caenorhabditis elegans lifespan and motor functions. RNA Biol 2015; 11:1148-60. [PMID: 25483032 DOI: 10.4161/rna.36100] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Spinal muscular atrophy (SMA), the most frequent human congenital motor neuron degenerative disease, is caused by loss-of-function mutations in the highly conserved survival motor neuron gene SMN1. Mutations in SMN could affect several molecular processes, among which aberrant pre-mRNA splicing caused by defective snRNP biogenesis is hypothesized as a major cause of SMA. To date little is known about the interactions of SMN with other splicing factor genes and how SMN affects splicing in vivo. The nematode Caenorhabditis elegans carries a single ortholog of SMN, smn-1, and has been used as a model for studying the molecular functions of SMN. We analyzed RNA splicing of reporter genes in an smn-1 deletion mutant and found that smn-1 is required for efficient splicing at weak 3' splice sites. Genetic studies indicate that the defective lifespan and motor functions of the smn-1 deletion mutants could be significantly improved by mutations of the splicing factor U2AF large subunit gene uaf-1. In smn-1 mutants we detected a reduced expression of U1 and U5 snRNAs and an increased expression of U2, U4 and U6 snRNAs. Our study verifies an essential role of smn-1 for RNA splicing in vivo, identifies the uaf-1 gene as a potential genetic modifier of smn-1 mutants, and suggests that SMN-1 has multifaceted effects on the expression of spliceosomal snRNAs.
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Affiliation(s)
- Xiaoyang Gao
- a State Key Laboratory of Medical Genetics; School of Life Sciences ; Central South University ; Changsha , Hunan , China
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21
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Mecham RP, Gibson MA. The microfibril-associated glycoproteins (MAGPs) and the microfibrillar niche. Matrix Biol 2015; 47:13-33. [PMID: 25963142 DOI: 10.1016/j.matbio.2015.05.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/23/2015] [Accepted: 03/24/2015] [Indexed: 10/23/2022]
Abstract
The microfibril-associated glycoproteins MAGP-1 and MAGP-2 are extracellular matrix proteins that interact with fibrillin to influence microfibril function. The two proteins are related through a 60 amino acid matrix-binding domain but their sequences differ outside of this region. A distinguishing feature of both proteins is their ability to interact with TGFβ family growth factors, Notch and Notch ligands, and multiple elastic fiber proteins. MAGP-2 can also interact with αvβ3 integrins via a RGD sequence that is not found in MAGP-1. Morpholino knockdown of MAGP-1 expression in zebrafish resulted in abnormal vessel wall architecture and altered vascular network formation. In the mouse, MAGP-1 deficiency had little effect on elastic fibers in blood vessels and lung but resulted in numerous unexpected phenotypes including bone abnormalities, hematopoietic changes, increased fat deposition, diabetes, impaired wound repair, and a bleeding diathesis. Inactivation of the gene for MAGP-2 in mice produced a neutropenia yet had minimal effects on bone or adipose homeostasis. Double knockouts had phenotypes characteristic of each individual knockout as well as several additional traits only seen when both genes are inactivated. A common mechanism underlying all of the traits associated with the knockout phenotypes is altered TGFβ signaling. This review summarizes our current understanding of the function of the MAGPs and discusses ideas related to their role in growth factor regulation.
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Affiliation(s)
- Robert P Mecham
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Mark A Gibson
- School of Medical Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
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22
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de la Cruz IP, Ma L, Horvitz HR. The Caenorhabditis elegans iodotyrosine deiodinase ortholog SUP-18 functions through a conserved channel SC-box to regulate the muscle two-pore domain potassium channel SUP-9. PLoS Genet 2014; 10:e1004175. [PMID: 24586202 PMCID: PMC3930498 DOI: 10.1371/journal.pgen.1004175] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Accepted: 12/28/2013] [Indexed: 02/04/2023] Open
Abstract
Loss-of-function mutations in the Caenorhabditis elegans gene sup-18 suppress the defects in muscle contraction conferred by a gain-of-function mutation in SUP-10, a presumptive regulatory subunit of the SUP-9 two-pore domain K+ channel associated with muscle membranes. We cloned sup-18 and found that it encodes the C. elegans ortholog of mammalian iodotyrosine deiodinase (IYD), an NADH oxidase/flavin reductase that functions in iodine recycling and is important for the biosynthesis of thyroid hormones that regulate metabolism. The FMN-binding site of mammalian IYD is conserved in SUP-18, which appears to require catalytic activity to function. Genetic analyses suggest that SUP-10 can function with SUP-18 to activate SUP-9 through a pathway that is independent of the presumptive SUP-9 regulatory subunit UNC-93. We identified a novel evolutionarily conserved serine-cysteine-rich region in the C-terminal cytoplasmic domain of SUP-9 required for its specific activation by SUP-10 and SUP-18 but not by UNC-93. Since two-pore domain K+ channels regulate the resting membrane potentials of numerous cell types, we suggest that the SUP-18 IYD regulates the activity of the SUP-9 channel using NADH as a coenzyme and thus couples the metabolic state of muscle cells to muscle membrane excitability. Iodotyrosine deiodinase (IYD) controls the recycling of iodide in the biogenesis of thyroid hormones that regulate metabolism. Defects in IYD result in congenital hypothyroidism, a multisystem disorder that can lead to growth failure and severe mental retardation. We identified the gene sup-18 of the nematode Caenorhabditis elegans as a regulator of the SUP-9/UNC-93/SUP-10 two-pore domain potassium channel complex and showed that SUP-18 is an ortholog of IYD, a member of the NADH oxidase/flavin reductase family. SUP-18 IYD is required for the activation of the channel complex by a gain-of-function mutation of the SUP-10 protein. SUP-9 channel activation by SUP-18 requires a conserved serine-cysteine-rich region in the C-terminus of SUP-9 and is independent of the function of the conserved multi-transmembrane protein UNC-93. We propose that SUP-18 uses NADH as a coenzyme to activate the SUP-9 channel in response to the activity of SUP-10 and the metabolic state of muscle cells.
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Affiliation(s)
- Ignacio Perez de la Cruz
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Long Ma
- State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - H. Robert Horvitz
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
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23
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Roukos DH, Katsouras CS, Baltogiannis GG, Naka KK, Michalis LK. Network-based drugs: promise and clinical challenges in cardiovascular disease. Expert Rev Proteomics 2013; 10:119-22. [DOI: 10.1586/epr.13.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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