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Zhang Z, Kumar V, Dybkov O, Will CL, Urlaub H, Stark H, Lührmann R. Cryo-EM analyses of dimerized spliceosomes provide new insights into the functions of B complex proteins. EMBO J 2024; 43:1065-1088. [PMID: 38383864 PMCID: PMC10943123 DOI: 10.1038/s44318-024-00052-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 02/23/2024] Open
Abstract
The B complex is a key intermediate stage of spliceosome assembly. To improve the structural resolution of monomeric, human spliceosomal B (hB) complexes and thereby generate a more comprehensive hB molecular model, we determined the cryo-EM structure of B complex dimers formed in the presence of ATP γ S. The enhanced resolution of these complexes allows a finer molecular dissection of how the 5' splice site (5'ss) is recognized in hB, and new insights into molecular interactions of FBP21, SNU23 and PRP38 with the U6/5'ss helix and with each other. It also reveals that SMU1 and RED are present as a heterotetrameric complex and are located at the interface of the B dimer protomers. We further show that MFAP1 and UBL5 form a 5' exon binding channel in hB, and elucidate the molecular contacts stabilizing the 5' exon at this stage. Our studies thus yield more accurate models of protein and RNA components of hB complexes. They further allow the localization of additional proteins and protein domains (such as SF3B6, BUD31 and TCERG1) whose position was not previously known, thereby uncovering new functions for B-specific and other hB proteins during pre-mRNA splicing.
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Affiliation(s)
- Zhenwei Zhang
- Department of Structural Dynamics, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Vinay Kumar
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Olexandr Dybkov
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- Bioanalytical Mass Spectrometry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Cindy L Will
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
| | - Holger Stark
- Department of Structural Dynamics, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany.
| | - Reinhard Lührmann
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany.
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Rogalska ME, Vivori C, Valcárcel J. Regulation of pre-mRNA splicing: roles in physiology and disease, and therapeutic prospects. Nat Rev Genet 2023; 24:251-269. [PMID: 36526860 DOI: 10.1038/s41576-022-00556-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2022] [Indexed: 12/23/2022]
Abstract
The removal of introns from mRNA precursors and its regulation by alternative splicing are key for eukaryotic gene expression and cellular function, as evidenced by the numerous pathologies induced or modified by splicing alterations. Major recent advances have been made in understanding the structures and functions of the splicing machinery, in the description and classification of physiological and pathological isoforms and in the development of the first therapies for genetic diseases based on modulation of splicing. Here, we review this progress and discuss important remaining challenges, including predicting splice sites from genomic sequences, understanding the variety of molecular mechanisms and logic of splicing regulation, and harnessing this knowledge for probing gene function and disease aetiology and for the design of novel therapeutic approaches.
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Affiliation(s)
- Malgorzata Ewa Rogalska
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Claudia Vivori
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain
- The Francis Crick Institute, London, UK
| | - Juan Valcárcel
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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Eberle AB, Mühlemann O. Tethered Function Assays to Elucidate the Role of RNA-Binding Proteins. Methods Mol Biol 2022; 2537:285-306. [PMID: 35895271 DOI: 10.1007/978-1-0716-2521-7_17] [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] [Indexed: 06/15/2023]
Abstract
The fate of each RNA molecule is strongly determined by RNA-binding proteins (RBPs) which accompany transcripts from its synthesis to its degradation. To elucidate the effect of a specific RBP on bound RNA, it can be artificially recruited to a specific site on a reporter mRNA that can be followed by a variety of methods. In this so-called tethering assay, the protein of interest (POI) is fused to the coat protein of the MS2 bacteriophage and expressed in your favorite cells together with a reporter gene containing MS2 binding sites. The MS2 binding sites are recognized by the MS2 coat protein (MS2CP) with high affinity and specificity and by doing so, the POI is tethered to the reporter RNA. Here, we describe how with the help of this assay the human cytoplasmic poly(A) binding protein is recruited to a mini-μ RNA reporter, thereby influencing the stability of the reporter transcript.
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Affiliation(s)
- Andrea B Eberle
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Oliver Mühlemann
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland.
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