1
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Fu X, Hoskins AA. Dynamics and Evolutionary Conservation of B Complex Protein Recruitment During Spliceosome Activation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.08.606642. [PMID: 39149324 PMCID: PMC11326307 DOI: 10.1101/2024.08.08.606642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Spliceosome assembly and catalytic site formation (called activation) involve dozens of protein and snRNA binding and unbinding events. The B-complex specific proteins Prp38, Snu23, and Spp381 have critical roles in stabilizing the spliceosome during conformational changes essential for activation. While these proteins are conserved, different mechanisms have been proposed for their recruitment to spliceosomes. To visualize recruitment directly, we used Colocalization Single Molecule Spectroscopy (CoSMoS) to study the dynamics of Prp38, Snu23, and Spp381 during splicing in real time. These proteins bind to and release from spliceosomes simultaneously and are likely associated with one another. We designate the complex of Prp38, Snu23, and Spp381 as the B Complex Protein (BCP) subcomplex. Under splicing conditions, the BCP associates with pre-mRNA after tri-snRNP binding. BCP release predominantly occurs after U4 snRNP dissociation and after NineTeen Complex (NTC) association. Under low concentrations of ATP, the BCP pre-associates with the tri-snRNP resulting in their simultaneous binding to pre-mRNA. Together, our results reveal that the BCP recruitment pathway to the spliceosome is conserved between S. cerevisiae and humans. Binding of the BCP to the tri-snRNP when ATP is limiting may result in formation of unproductive complexes that could be used to regulate splicing.
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Affiliation(s)
- Xingyang Fu
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Current Address: Department of Neuroscience, Yale University, New Haven, CT, 06520, USA
| | - Aaron A. Hoskins
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
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2
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Vorländer MK, Rothe P, Kleifeld J, Cormack ED, Veleti L, Riabov-Bassat D, Fin L, Phillips AW, Cochella L, Plaschka C. Mechanism for the initiation of spliceosome disassembly. Nature 2024; 632:443-450. [PMID: 38925148 DOI: 10.1038/s41586-024-07741-1] [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: 12/15/2023] [Accepted: 06/19/2024] [Indexed: 06/28/2024]
Abstract
Precursor-mRNA (pre-mRNA) splicing requires the assembly, remodelling and disassembly of the multi-megadalton ribonucleoprotein complex called the spliceosome1. Recent studies have shed light on spliceosome assembly and remodelling for catalysis2-6, but the mechanism of disassembly remains unclear. Here we report cryo-electron microscopy structures of nematode and human terminal intron lariat spliceosomes along with biochemical and genetic data. Our results uncover how four disassembly factors and the conserved RNA helicase DHX15 initiate spliceosome disassembly. The disassembly factors probe large inner and outer spliceosome surfaces to detect the release of ligated mRNA. Two of these factors, TFIP11 and C19L1, and three general spliceosome subunits, SYF1, SYF2 and SDE2, then dock and activate DHX15 on the catalytic U6 snRNA to initiate disassembly. U6 therefore controls both the start5 and end of pre-mRNA splicing. Taken together, our results explain the molecular basis of the initiation of canonical spliceosome disassembly and provide a framework to understand general spliceosomal RNA helicase control and the discard of aberrant spliceosomes.
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Affiliation(s)
- Matthias K Vorländer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Patricia Rothe
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Justus Kleifeld
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Eric D Cormack
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lalitha Veleti
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Daria Riabov-Bassat
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Laura Fin
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Alex W Phillips
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Luisa Cochella
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria.
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Clemens Plaschka
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria.
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3
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Zhan X, Lu Y, Shi Y. Molecular basis for the activation of human spliceosome. Nat Commun 2024; 15:6348. [PMID: 39068178 PMCID: PMC11283556 DOI: 10.1038/s41467-024-50785-0] [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: 02/25/2024] [Accepted: 07/20/2024] [Indexed: 07/30/2024] Open
Abstract
The spliceosome executes pre-mRNA splicing through four sequential stages: assembly, activation, catalysis, and disassembly. Activation of the spliceosome, namely remodeling of the pre-catalytic spliceosome (B complex) into the activated spliceosome (Bact complex) and the catalytically activated spliceosome (B* complex), involves major flux of protein components and structural rearrangements. Relying on a splicing inhibitor, we have captured six intermediate states between the B and B* complexes: pre-Bact, Bact-I, Bact-II, Bact-III, Bact-IV, and post-Bact. Their cryo-EM structures, together with an improved structure of the catalytic step I spliceosome (C complex), reveal how the catalytic center matures around the internal stem loop of U6 snRNA, how the branch site approaches 5'-splice site, how the RNA helicase PRP2 rearranges to bind pre-mRNA, and how U2 snRNP undergoes remarkable movement to facilitate activation. We identify a previously unrecognized key role of PRP2 in spliceosome activation. Our study recapitulates a molecular choreography of the human spliceosome during its catalytic activation.
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Affiliation(s)
- Xiechao Zhan
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China.
- Research Center for Industries of the Future, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China.
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China.
| | - Yichen Lu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- Research Center for Industries of the Future, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
- College of Life Sciences, Fudan University, Shanghai, China
| | - Yigong Shi
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China.
- Research Center for Industries of the Future, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China.
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China.
- Beijing Frontier Research Center for Biological Structure, Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China.
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4
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Clarke BP, Angelos AE, Mei M, Hill PS, Xie Y, Ren Y. Cryo-EM structure of the CBC-ALYREF complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.01.559959. [PMID: 37873070 PMCID: PMC10592852 DOI: 10.1101/2023.10.01.559959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
In eukaryotes, RNAs transcribed by RNA Pol II are modified at the 5' end with a 7-methylguanosine (m 7 G) cap, which is recognized by the nuclear cap binding complex (CBC). The CBC plays multiple important roles in mRNA metabolism including transcription, splicing, polyadenylation, and export. It promotes mRNA export through direct interaction with a key mRNA export factor, ALYREF, which in turn links the TRanscription and EXport (TREX) complex to the 5' end of mRNA. However, the molecular mechanism for CBC mediated recruitment of the mRNA export machinery is not well understood. Here, we present the first structure of the CBC in complex with an mRNA export factor, ALYREF. The cryo-EM structure of CBC-ALYREF reveals that the RRM domain of ALYREF makes direct contact with both the NCBP1 and NCBP2 subunits of the CBC. Comparing CBC-ALYREF with other cellular complexes containing CBC and/or ALYREF components provides insights into the coordinated events during mRNA transcription, splicing, and export.
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5
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Senn KA, Lipinski KA, Zeps NJ, Griffin AF, Wilkinson ME, Hoskins AA. Control of 3' splice site selection by the yeast splicing factor Fyv6. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.04.592262. [PMID: 38746449 PMCID: PMC11092753 DOI: 10.1101/2024.05.04.592262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Pre-mRNA splicing is catalyzed in two steps: 5' splice site (SS) cleavage and exon ligation. A number of proteins transiently associate with spliceosomes to specifically impact these steps (1st and 2nd step factors). We recently identified Fyv6 (FAM192A in humans) as a 2nd step factor in S. cerevisiae; however, we did not determine how widespread Fyv6's impact is on the transcriptome. To answer this question, we have used RNA-seq to analyze changes in splicing. These results show that loss of Fyv6 results in activation of non-consensus, branch point (BP) proximal 3' SS transcriptome-wide. To identify the molecular basis of these observations, we determined a high-resolution cryo-EM structure of a yeast product complex spliceosome containing Fyv6 at 2.3 Å. The structure reveals that Fyv6 is the only 2nd step factor that contacts the Prp22 ATPase and that Fyv6 binding is mutually exclusive with that of the 1st step factor Yju2. We then use this structure to dissect Fyv6 functional domains and interpret results of a genetic screen for fyv6Δ suppressor mutations. The combined transcriptomic, structural, and genetic studies allow us to propose a model in which Yju2/Fyv6 exchange facilitates exon ligation and Fyv6 promotes usage of consensus, BP distal 3' SS.
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Affiliation(s)
- Katherine A. Senn
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Karli A. Lipinski
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Natalie J. Zeps
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Amory F. Griffin
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Max E. Wilkinson
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH UK
- Present Addresses: Broad Institute of MIT and Harvard, Cambridge MA 02142 USA and McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - Aaron A. Hoskins
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
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6
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Yang Z, Li H, Zang D, Han R, Zhang F. Improved Denoising of Cryo-Electron Microscopy Micrographs with Simulation-Aware Pretraining. J Comput Biol 2024; 31:564-575. [PMID: 38805340 DOI: 10.1089/cmb.2024.0513] [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: 05/30/2024] Open
Abstract
Cryo-electron microscopy (cryo-EM) has emerged as a potent technique for determining the structure and functionality of biological macromolecules. However, limited by the physical imaging conditions, such as low electron beam dose, micrographs in cryo-EM typically contend with an extremely low signal-to-noise ratio (SNR), impeding the efficiency and efficacy of subsequent analyses. Therefore, there is a growing demand for an efficient denoising algorithm designed for cryo-EM micrographs, aiming to enhance the quality of macromolecular analysis. However, owing to the absence of a comprehensive and well-defined dataset with ground truth images, supervised image denoising methods exhibit limited generalization when applied to experimental micrographs. To tackle this challenge, we introduce a simulation-aware image denoising (SaID) pretrained model designed to enhance the SNR of cryo-EM micrographs where the training is solely based on an accurately simulated dataset. First, we propose a parameter calibration algorithm for simulated dataset generation, aiming to align simulation parameters with those of experimental micrographs. Second, leveraging the accurately simulated dataset, we propose to train a deep general denoising model that can well generalize to real experimental cryo-EM micrographs. Comprehensive experimental results demonstrate that our pretrained denoising model achieves excellent denoising performance on experimental cryo-EM micrographs, significantly streamlining downstream analysis.
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Affiliation(s)
- Zhidong Yang
- High Performance Computer Research Center, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hongjia Li
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Dawei Zang
- High Performance Computer Research Center, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China
| | - Renmin Han
- Research Center for Mathematics and Interdisciplinary Sciences, Frontiers Science Center for Nonlinear Expectations (Ministry of Education), Shandong University, Qingdao, China
| | - Fa Zhang
- School of Medical Technology, Beijing Institute of Technology, Beijing, China
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7
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Segovia D, Adams DW, Hoffman N, Safaric Tepes P, Wee TL, Cifani P, Joshua-Tor L, Krainer AR. SRSF1 interactome determined by proximity labeling reveals direct interaction with spliceosomal RNA helicase DDX23. Proc Natl Acad Sci U S A 2024; 121:e2322974121. [PMID: 38743621 PMCID: PMC11126954 DOI: 10.1073/pnas.2322974121] [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: 01/03/2024] [Accepted: 04/15/2024] [Indexed: 05/16/2024] Open
Abstract
SRSF1 is the founding member of the SR protein family. It is required-interchangeably with other SR proteins-for pre-mRNA splicing in vitro, and it regulates various alternative splicing events. Dysregulation of SRSF1 expression contributes to cancer and other pathologies. Here, we characterized SRSF1's interactome using proximity labeling and mass spectrometry. This approach yielded 190 proteins enriched in the SRSF1 samples, independently of the N- or C-terminal location of the biotin-labeling domain. The detected proteins reflect established functions of SRSF1 in pre-mRNA splicing and reveal additional connections to spliceosome proteins, in addition to other recently identified functions. We validated a robust interaction with the spliceosomal RNA helicase DDX23/PRP28 using bimolecular fluorescence complementation and in vitro binding assays. The interaction is mediated by the N-terminal RS-like domain of DDX23 and both RRM1 and the RS domain of SRSF1. During pre-mRNA splicing, DDX23's ATPase activity is essential for the pre-B to B spliceosome complex transition and for release of U1 snRNP from the 5' splice site. We show that the RS-like region of DDX23's N-terminal domain is important for spliceosome incorporation, while larger deletions in this domain alter subnuclear localization. We discuss how the identified interaction of DDX23 with SRSF1 and other SR proteins may be involved in the regulation of these processes.
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Affiliation(s)
- Danilo Segovia
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY11724
- Graduate Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, NY11794
| | - Dexter W. Adams
- HHMI, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY11724
- W. M. Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY11724
- Graduate Program in Genetics, Stony Brook University, Stony Brook, NY11794
| | | | | | - Tse-Luen Wee
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY11724
| | - Paolo Cifani
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY11724
| | - Leemor Joshua-Tor
- HHMI, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY11724
- W. M. Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY11724
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8
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Atkinson R, Georgiou M, Yang C, Szymanska K, Lahat A, Vasconcelos EJR, Ji Y, Moya Molina M, Collin J, Queen R, Dorgau B, Watson A, Kurzawa-Akanbi M, Laws R, Saxena A, Shyan Beh C, Siachisumo C, Goertler F, Karwatka M, Davey T, Inglehearn CF, McKibbin M, Lührmann R, Steel DH, Elliott DJ, Armstrong L, Urlaub H, Ali RR, Grellscheid SN, Johnson CA, Mozaffari-Jovin S, Lako M. PRPF8-mediated dysregulation of hBrr2 helicase disrupts human spliceosome kinetics and 5´-splice-site selection causing tissue-specific defects. Nat Commun 2024; 15:3138. [PMID: 38605034 PMCID: PMC11009313 DOI: 10.1038/s41467-024-47253-0] [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: 09/21/2023] [Accepted: 03/19/2024] [Indexed: 04/13/2024] Open
Abstract
The carboxy-terminus of the spliceosomal protein PRPF8, which regulates the RNA helicase Brr2, is a hotspot for mutations causing retinitis pigmentosa-type 13, with unclear role in human splicing and tissue-specificity mechanism. We used patient induced pluripotent stem cells-derived cells, carrying the heterozygous PRPF8 c.6926 A > C (p.H2309P) mutation to demonstrate retinal-specific endophenotypes comprising photoreceptor loss, apical-basal polarity and ciliary defects. Comprehensive molecular, transcriptomic, and proteomic analyses revealed a role of the PRPF8/Brr2 regulation in 5'-splice site (5'SS) selection by spliceosomes, for which disruption impaired alternative splicing and weak/suboptimal 5'SS selection, and enhanced cryptic splicing, predominantly in ciliary and retinal-specific transcripts. Altered splicing efficiency, nuclear speckles organisation, and PRPF8 interaction with U6 snRNA, caused accumulation of active spliceosomes and poly(A)+ mRNAs in unique splicing clusters located at the nuclear periphery of photoreceptors. Collectively these elucidate the role of PRPF8/Brr2 regulatory mechanisms in splicing and the molecular basis of retinal disease, informing therapeutic approaches.
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Affiliation(s)
| | - Maria Georgiou
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Chunbo Yang
- Biosciences Institute, Newcastle University, Newcastle, UK
| | | | - Albert Lahat
- Department of Biosciences, Durham University, Durham, UK
| | | | - Yanlong Ji
- Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Marina Moya Molina
- Biosciences Institute, Newcastle University, Newcastle, UK
- Newcells Biotech, Newcastle, UK
| | - Joseph Collin
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Rachel Queen
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Birthe Dorgau
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Avril Watson
- Biosciences Institute, Newcastle University, Newcastle, UK
- Newcells Biotech, Newcastle, UK
| | | | - Ross Laws
- Electron Microscopy Research Services, Newcastle University, Newcastle, UK
| | - Abhijit Saxena
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Chia Shyan Beh
- Biosciences Institute, Newcastle University, Newcastle, UK
| | | | | | | | - Tracey Davey
- Electron Microscopy Research Services, Newcastle University, Newcastle, UK
| | | | - Martin McKibbin
- Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Reinhard Lührmann
- Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - David H Steel
- Biosciences Institute, Newcastle University, Newcastle, UK
| | | | - Lyle Armstrong
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Henning Urlaub
- Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
- Göttingen Center for Molecular Biosciences, Georg August University of Göttingen, Göttingen, Germany
| | - Robin R Ali
- Centre for Cell and Gene Therapy, Kings College London, London, UK
| | - Sushma-Nagaraja Grellscheid
- Department of Biosciences, Durham University, Durham, UK
- Department of Informatics, University of Bergen, Bergen, Norway
| | - Colin A Johnson
- Leeds Institute of Medical Research, University of Leeds, Leeds, UK.
| | - Sina Mozaffari-Jovin
- Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany.
- Department of Medical Genetics and Medical Genetics Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Majlinda Lako
- Biosciences Institute, Newcastle University, Newcastle, UK.
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9
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Shen L, Ma X, Wang Y, Wang Z, Zhang Y, Pham HQH, Tao X, Cui Y, Wei J, Lin D, Abeywanada T, Hardikar S, Halabelian L, Smith N, Chen T, Barsyte-Lovejoy D, Qiu S, Xing Y, Yang Y. Loss-of-function mutation in PRMT9 causes abnormal synapse development by dysregulation of RNA alternative splicing. Nat Commun 2024; 15:2809. [PMID: 38561334 PMCID: PMC10984984 DOI: 10.1038/s41467-024-47107-9] [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: 07/18/2023] [Accepted: 03/16/2024] [Indexed: 04/04/2024] Open
Abstract
Protein arginine methyltransferase 9 (PRMT9) is a recently identified member of the PRMT family, yet its biological function remains largely unknown. Here, by characterizing an intellectual disability associated PRMT9 mutation (G189R) and establishing a Prmt9 conditional knockout (cKO) mouse model, we uncover an important function of PRMT9 in neuronal development. The G189R mutation abolishes PRMT9 methyltransferase activity and reduces its protein stability. Knockout of Prmt9 in hippocampal neurons causes alternative splicing of ~1900 genes, which likely accounts for the aberrant synapse development and impaired learning and memory in the Prmt9 cKO mice. Mechanistically, we discover a methylation-sensitive protein-RNA interaction between the arginine 508 (R508) of the splicing factor 3B subunit 2 (SF3B2), the site that is exclusively methylated by PRMT9, and the pre-mRNA anchoring site, a cis-regulatory element that is critical for RNA splicing. Additionally, using human and mouse cell lines, as well as an SF3B2 arginine methylation-deficient mouse model, we provide strong evidence that SF3B2 is the primary methylation substrate of PRMT9, thus highlighting the conserved function of the PRMT9/SF3B2 axis in regulating pre-mRNA splicing.
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Affiliation(s)
- Lei Shen
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
| | - Xiaokuang Ma
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, 85004, USA
| | - Yuanyuan Wang
- Bioinformatics Interdepartmental Graduate Program, University of California, Los Angeles, CA, 90095, USA
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Zhihao Wang
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
| | - Yi Zhang
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
| | - Hoang Quoc Hai Pham
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
- Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope, Duarte, CA, 91010, USA
| | - Xiaoqun Tao
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
- Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope, Duarte, CA, 91010, USA
| | - Yuehua Cui
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, 85004, USA
| | - Jing Wei
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, 85004, USA
| | - Dimitri Lin
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
| | - Tharindumala Abeywanada
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
| | - Swanand Hardikar
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Levon Halabelian
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
| | - Noah Smith
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Taiping Chen
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | | | - Shenfeng Qiu
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, 85004, USA.
| | - Yi Xing
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
| | - Yanzhong Yang
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA.
- Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope, Duarte, CA, 91010, USA.
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10
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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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11
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Dubiez E, Pellegrini E, Finderup Brask M, Garland W, Foucher AE, Huard K, Heick Jensen T, Cusack S, Kadlec J. Structural basis for competitive binding of productive and degradative co-transcriptional effectors to the nuclear cap-binding complex. Cell Rep 2024; 43:113639. [PMID: 38175753 DOI: 10.1016/j.celrep.2023.113639] [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: 07/17/2023] [Revised: 11/07/2023] [Accepted: 12/15/2023] [Indexed: 01/06/2024] Open
Abstract
The nuclear cap-binding complex (CBC) coordinates co-transcriptional maturation, transport, or degradation of nascent RNA polymerase II (Pol II) transcripts. CBC with its partner ARS2 forms mutually exclusive complexes with diverse "effectors" that promote either productive or destructive outcomes. Combining AlphaFold predictions with structural and biochemical validation, we show how effectors NCBP3, NELF-E, ARS2, PHAX, and ZC3H18 form competing binary complexes with CBC and how PHAX, NCBP3, ZC3H18, and other effectors compete for binding to ARS2. In ternary CBC-ARS2 complexes with PHAX, NCBP3, or ZC3H18, ARS2 is responsible for the initial effector recruitment but inhibits their direct binding to the CBC. We show that in vivo ZC3H18 binding to both CBC and ARS2 is required for nuclear RNA degradation. We propose that recruitment of PHAX to CBC-ARS2 can lead, with appropriate cues, to competitive displacement of ARS2 and ZC3H18 from the CBC, thus promoting a productive rather than a degradative RNA fate.
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Affiliation(s)
- Etienne Dubiez
- European Molecular Biology Laboratory, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France; Univ. Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | - Erika Pellegrini
- European Molecular Biology Laboratory, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Maja Finderup Brask
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - William Garland
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | | | - Karine Huard
- European Molecular Biology Laboratory, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Stephen Cusack
- European Molecular Biology Laboratory, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France.
| | - Jan Kadlec
- Univ. Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France.
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12
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Chen Y, Zhang X, Zhang M, Fan W, Lin Y, Li G. UTP11 promotes the growth of hepatocellular carcinoma by enhancing the mRNA stability of Oct4. BMC Cancer 2024; 24:93. [PMID: 38233795 PMCID: PMC10795422 DOI: 10.1186/s12885-023-11794-2] [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: 04/14/2023] [Accepted: 12/24/2023] [Indexed: 01/19/2024] Open
Abstract
BACKGROUND Several publications suggest that UTP11 may be a promising gene engaged for involvement of hepatocellular carcinoma (HCC) pathology. However, there are extremely limited biological, mechanistic and clinical studies of UTP11 in HCC. METHODS To anayze the UTP11 mRNA expression in HCC and normal clinical samples and further investigate the correlation between UTP11 expression and pathology and clinical prognosis via the Cancer Tissue Gene Atlas (TCGA) database. The protein levels of UTP11 were checked using the Human Protein Atlas (HPA) database. GO-KEGG enrichment was performed from Cancer Cell Line Encyclopedia (CCLE) database and TCGA dataset. The levels of UTP11 were tested with qRT-PCR and western blotting assays. Cell viability, immunofluorescence and flow cytometry assays and animal models were used to explore the potential involvement of UTP11 in regulating HCC growth in vitro and in vivo. The correlation of UTP11 and tumor stemness scores and stemness-associated proteins from TCGA database. The mRNA stability was treated with Actinomycin D, followed by testing the mRNA expression using qRT-PCR assay. RESULTS UTP11 was highly expressed in HCC samples compared to normal tissues from TCGA database. Similarly, UTP11 protein expression levels were obviously elevated in HCC tissue samples from HPA database. Furthermore, UTP11 levels were correlated with poor prognosis in HCC patient samples in TCGA dataset. In addition, the UTP11 mRNA levels was notably enhanced in different HCC cell lines than in normal liver cells and knocking down UTP11 was obviously reduced the viability and cell death of HCC cells. UTP11 knockdown suppressed the tumor growth of HCC in vivo experiment and extended the mice survival time. GO-KEEG analysis from CCLE and TCGA database suggested that UTP11 might involve in RNA splicing and the stability of mRNA. Further, UTP11 was positively correlated with tumor stemness scores and stemness-associated proteins from TCGA database. Knockdown of UTP11 was reduced the expression of stem cell-related genes and regulated the mRNA stability of Oct4. CONCLUSIONS UTP11 is potentially a diagnostic molecule and a therapeutic candidate for treatment of HCC.
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Affiliation(s)
- Yan Chen
- Department of Gastroenterology, The Second Affiliated Hospital of Shandong First Medical University, Tai an City, China
| | - Xiaowei Zhang
- Department of Gastroenterology, The Second Affiliated Hospital of Shandong First Medical University, Tai an City, China
| | - Mingcheng Zhang
- Department of Endoscopy Center, The Second Affiliated Hospital of Shandong First Medical University, Tai an City, China
| | - Wenting Fan
- Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Shandong First Medical University, 271000, Tai an City, China
| | - Yueyue Lin
- Department of Endoscopy Center, The Second Affiliated Hospital of Shandong First Medical University, Tai an City, China
| | - Guodong Li
- Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Shandong First Medical University, 271000, Tai an City, China.
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13
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Chung CS, Wai HL, Kao CY, Cheng SC. An ATP-independent role for Prp16 in promoting aberrant splicing. Nucleic Acids Res 2023; 51:10815-10828. [PMID: 37858289 PMCID: PMC10639067 DOI: 10.1093/nar/gkad861] [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: 06/30/2023] [Revised: 09/03/2023] [Accepted: 09/23/2023] [Indexed: 10/21/2023] Open
Abstract
The spliceosome is assembled through a step-wise process of binding and release of its components to and from the pre-mRNA. The remodeling process is facilitated by eight DExD/H-box RNA helicases, some of which have also been implicated in splicing fidelity control. In this study, we unveil a contrasting role for the prototypic splicing proofreader, Prp16, in promoting the utilization of aberrant 5' splice sites and mutated branchpoints. Prp16 is not essential for the branching reaction in wild-type pre-mRNA. However, when a mutation is present at the 5' splice site or if Cwc24 is absent, Prp16 facilitates the reaction and encourages aberrant 5' splice site usage independently of ATP. Prp16 also promotes the utilization of mutated branchpoints while preventing the use of nearby cryptic branch sites. Our study demonstrates that Prp16 can either enhance or impede the utilization of faulty splice sites by stabilizing or destabilizing interactions with other splicing components. Thus, Prp16 exerts dual roles in 5' splice site and branch site selection, via ATP-dependent and ATP-independent activities. Furthermore, we provide evidence that these functions of Prp16 are mediated through the step-one factor Cwc25.
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Affiliation(s)
- Che-Sheng Chung
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 115, Republic of China
| | - Hsu Lei Wai
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 115, Republic of China
| | - Ching-Yang Kao
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 115, Republic of China
| | - Soo-Chen Cheng
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 115, Republic of China
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14
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Zhang M, Chen C, Lu Z, Cai Y, Li Y, Zhang F, Liu Y, Chen S, Zhang H, Yang S, Gen H, Jiang Y, Ning C, Huang J, Wang W, Fan L, Zhang Y, Jin M, Han J, Xiong Z, Cai M, Liu J, Huang C, Yang X, Xu B, Li H, Li B, Zhu X, Wei Y, Zhu Y, Tian J, Miao X. Genetic Control of Alternative Splicing and its Distinct Role in Colorectal Cancer Mechanisms. Gastroenterology 2023; 165:1151-1167. [PMID: 37541527 DOI: 10.1053/j.gastro.2023.07.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 07/20/2023] [Accepted: 07/23/2023] [Indexed: 08/06/2023]
Abstract
BACKGROUND & AIMS Dysregulation of alternative splicing is implicated in many human diseases, and understanding the genetic variation underlying transcript splicing is essential to dissect the molecular mechanisms of cancers. We aimed to provide a comprehensive functional dissection of splicing quantitative trait loci (sQTLs) in cancer and focus on elucidating its distinct role in colorectal cancer (CRC) mechanisms. METHODS We performed a comprehensive sQTL analysis to identify genetic variants that control messenger RNA splicing across 33 cancer types from The Cancer Genome Atlas and independently validated in our 154 CRC tissues. Then, large-scale, multicenter, multi-ethnic case-control studies (34,585 cases and 76,023 controls) were conducted to examine the association of these sQTLs with CRC risk. A series of biological experiments in vitro and in vivo were performed to investigate the potential mechanisms of the candidate sQTLs and target genes. RESULTS The molecular characterization of sQTL revealed its distinct role in cancer susceptibility. Tumor-specific sQTL further showed better response to cancer development. In addition, functionally informed polygenic risk score highlighted the potentiality of sQTLs in the CRC prediction. Complemented by large-scale population studies, we identified that the risk allele (T) of a multi-ancestry-associated sQTL rs61746794 significantly increased the risk of CRC in Chinese (odds ratio, 1.20; 95% CI, 1.12-1.29; P = 8.82 × 10-7) and European (odds ratio, 1.11; 95% CI, 1.07-1.16; P = 1.13 × 10-7) populations. rs61746794-T facilitated PRMT7 exon 16 splicing mediated by the RNA-binding protein PRPF8, thus increasing the level of canonical PRMT7 isoform (PRMT7-V2). Overexpression of PRMT7-V2 significantly enhanced the growth of CRC cells and xenograft tumors compared with PRMT7-V1. Mechanistically, PRMT7-V2 functions as an epigenetic writer that catalyzes the arginine methylation of H4R3 and H3R2, subsequently regulating diverse biological processes, including YAP, AKT, and KRAS pathway. A selective PRMT7 inhibitor, SGC3027, exhibited antitumor effects on human CRC cells. CONCLUSIONS Our study provides an informative sQTLs resource and insights into the regulatory mechanisms linking splicing variants to cancer risk and serving as biomarkers and therapeutic targets.
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Affiliation(s)
- Ming Zhang
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China; Department of Radiation Oncology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Can Chen
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China; Department of Radiation Oncology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zequn Lu
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China; Department of Radiation Oncology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yimin Cai
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Yanmin Li
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Fuwei Zhang
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Yizhuo Liu
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Shuoni Chen
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Heng Zhang
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Shuhui Yang
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Hui Gen
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Yuan Jiang
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Caibo Ning
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Jinyu Huang
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Wenzhuo Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Linyun Fan
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Yi Zhang
- Department of Hygiene Toxicology, School of Public Health, Zunyi Medical University, Zunyi, Guizhou, China
| | - Meng Jin
- Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jinxin Han
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhen Xiong
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ming Cai
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiuyang Liu
- Department of Gastrointestinal Surgery, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Chaoqun Huang
- Department of Gastrointestinal Surgery, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Xiaojun Yang
- Department of Gastrointestinal Surgery, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Bin Xu
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Heng Li
- Department of Urology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bin Li
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Xu Zhu
- Department of Gastrointestinal Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yongchang Wei
- Department of Gastrointestinal Oncology, Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Ying Zhu
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Jianbo Tian
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China; Department of Radiation Oncology, Renmin Hospital of Wuhan University, Wuhan, China.
| | - Xiaoping Miao
- Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University; Department of Gastrointestinal Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China; Department of Radiation Oncology, Renmin Hospital of Wuhan University, Wuhan, China; Jiangsu Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China; Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Sciences and Technology, Wuhan, China.
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15
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Sharma T, Kundu N, Kaur S, Shankaraswamy J, Saxena S. Why to target G-quadruplexes using peptides: Next-generation G4-interacting ligands. J Pept Sci 2023; 29:e3491. [PMID: 37009771 DOI: 10.1002/psc.3491] [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: 11/18/2022] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 04/04/2023]
Abstract
Guanine-rich oligonucleotides existing in both DNA and RNA are able to fold into four-stranded DNA secondary structures via Hoogsteen type hydrogen-bonding, where four guanines self-assemble into a square planar arrangement, which, when stacked upon each other, results in the formation of higher-order structures called G-quadruplexes. Their distribution is not random; they are more frequently present at telomeres, proto-oncogenic promoters, introns, 5'- and 3'-untranslated regions, stem cell markers, ribosome binding sites and so forth and are associated with various biological functions, all of which play a pivotal role in various incurable diseases like cancer and cellular ageing. Several studies have suggested that G-quadruplexes could not regulate biological processes by themselves; instead, various proteins take part in this regulation and can be important therapeutic targets. There are certain limitations in using whole G4-protein for therapeutics purpose because of its high manufacturing cost, laborious structure prediction, dynamic nature, unavailability for oral administration due to its degradation in the gut and inefficient penetration to reach the target site because of the large size. Hence, biologically active peptides can be the potential candidates for therapeutic intervention instead of the whole G4-protein complex. In this review, we aimed to clarify the biological roles of G4s, how we can identify them throughout the genome via bioinformatics, the proteins interacting with G4s and how G4-interacting peptide molecules may be the potential next-generation ligands for targeting the G4 motifs located in biologically important regions.
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Affiliation(s)
- Taniya Sharma
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Nikita Kundu
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Sarvpreet Kaur
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Jadala Shankaraswamy
- Department of Fruit Science, College of Horticulture, Mojerla, Sri Konda Laxman Telangana State Horticultural University, Budwel, Telangana, India
| | - Sarika Saxena
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
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16
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Black CS, Whelan TA, Garside EL, MacMillan AM, Fast NM, Rader SD. Spliceosome assembly and regulation: insights from analysis of highly reduced spliceosomes. RNA (NEW YORK, N.Y.) 2023; 29:531-550. [PMID: 36737103 PMCID: PMC10158995 DOI: 10.1261/rna.079273.122] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 01/06/2023] [Indexed: 05/06/2023]
Abstract
Premessenger RNA splicing is catalyzed by the spliceosome, a multimegadalton RNA-protein complex that assembles in a highly regulated process on each intronic substrate. Most studies of splicing and spliceosomes have been carried out in human or S. cerevisiae model systems. There exists, however, a large diversity of spliceosomes, particularly in organisms with reduced genomes, that suggests a means of analyzing the essential elements of spliceosome assembly and regulation. In this review, we characterize changes in spliceosome composition across phyla, describing those that are most frequently observed and highlighting an analysis of the reduced spliceosome of the red alga Cyanidioschyzon merolae We used homology modeling to predict what effect splicing protein loss would have on the spliceosome, based on currently available cryo-EM structures. We observe strongly correlated loss of proteins that function in the same process, for example, in interacting with the U1 snRNP (which is absent in C. merolae), regulation of Brr2, or coupling transcription and splicing. Based on our observations, we predict splicing in C. merolae to be inefficient, inaccurate, and post-transcriptional, consistent with the apparent trend toward its elimination in this lineage. This work highlights the striking flexibility of the splicing pathway and the spliceosome when viewed in the context of eukaryotic diversity.
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Affiliation(s)
- Corbin S Black
- Department of Chemistry and Biochemistry, University of Northern British Columbia, Prince George, British Columbia, Canada V2N 4Z9
- Department of Anatomy and Cell Biology, McGill University, Montréal, Quebec, Canada H3A 0C7
| | - Thomas A Whelan
- Biodiversity Research Center and Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Erin L Garside
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | - Andrew M MacMillan
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | - Naomi M Fast
- Biodiversity Research Center and Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Stephen D Rader
- Department of Chemistry and Biochemistry, University of Northern British Columbia, Prince George, British Columbia, Canada V2N 4Z9
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17
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Bartolec TK, Vázquez-Campos X, Norman A, Luong C, Johnson M, Payne RJ, Wilkins MR, Mackay JP, Low JKK. Cross-linking mass spectrometry discovers, evaluates, and corroborates structures and protein-protein interactions in the human cell. Proc Natl Acad Sci U S A 2023; 120:e2219418120. [PMID: 37071682 PMCID: PMC10151615 DOI: 10.1073/pnas.2219418120] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/16/2023] [Indexed: 04/19/2023] Open
Abstract
Significant recent advances in structural biology, particularly in the field of cryoelectron microscopy, have dramatically expanded our ability to create structural models of proteins and protein complexes. However, many proteins remain refractory to these approaches because of their low abundance, low stability, or-in the case of complexes-simply not having yet been analyzed. Here, we demonstrate the power of using cross-linking mass spectrometry (XL-MS) for the high-throughput experimental assessment of the structures of proteins and protein complexes. This included those produced by high-resolution but in vitro experimental data, as well as in silico predictions based on amino acid sequence alone. We present the largest XL-MS dataset to date, describing 28,910 unique residue pairs captured across 4,084 unique human proteins and 2,110 unique protein-protein interactions. We show that models of proteins and their complexes predicted by AlphaFold2, and inspired and corroborated by the XL-MS data, offer opportunities to deeply mine the structural proteome and interactome and reveal mechanisms underlying protein structure and function.
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Affiliation(s)
- Tara K. Bartolec
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Randwick, NSW2052, Australia
| | - Xabier Vázquez-Campos
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Randwick, NSW2052, Australia
| | - Alexander Norman
- School of Chemistry, University of Sydney, Sydney, NSW2006, Australia
| | - Clement Luong
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW2006, Australia
| | - Marcus Johnson
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW2006, Australia
| | - Richard J. Payne
- School of Chemistry, University of Sydney, Sydney, NSW2006, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, NSW2006, Australia
| | - Marc R. Wilkins
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Randwick, NSW2052, Australia
| | - Joel P. Mackay
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW2006, Australia
| | - Jason K. K. Low
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW2006, Australia
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18
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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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19
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Dybkov O, Preußner M, El Ayoubi L, Feng VY, Harnisch C, Merz K, Leupold P, Yudichev P, Agafonov DE, Will CL, Girard C, Dienemann C, Urlaub H, Kastner B, Heyd F, Lührmann R. Regulation of 3' splice site selection after step 1 of splicing by spliceosomal C* proteins. SCIENCE ADVANCES 2023; 9:eadf1785. [PMID: 36867703 PMCID: PMC9984181 DOI: 10.1126/sciadv.adf1785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
Alternative precursor messenger RNA splicing is instrumental in expanding the proteome of higher eukaryotes, and changes in 3' splice site (3'ss) usage contribute to human disease. We demonstrate by small interfering RNA-mediated knockdowns, followed by RNA sequencing, that many proteins first recruited to human C* spliceosomes, which catalyze step 2 of splicing, regulate alternative splicing, including the selection of alternatively spliced NAGNAG 3'ss. Cryo-electron microscopy and protein cross-linking reveal the molecular architecture of these proteins in C* spliceosomes, providing mechanistic and structural insights into how they influence 3'ss usage. They further elucidate the path of the 3' region of the intron, allowing a structure-based model for how the C* spliceosome potentially scans for the proximal 3'ss. By combining biochemical and structural approaches with genome-wide functional analyses, our studies reveal widespread regulation of alternative 3'ss usage after step 1 of splicing and the likely mechanisms whereby C* proteins influence NAGNAG 3'ss choices.
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Affiliation(s)
- Olexandr Dybkov
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Marco Preußner
- Institut für Chemie und Biochemie, RNA Biochemie, Freie Universität Berlin, Takustr. 6, Berlin 14195, Germany
| | - Leyla El Ayoubi
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Vivi-Yun Feng
- Institut für Chemie und Biochemie, RNA Biochemie, Freie Universität Berlin, Takustr. 6, Berlin 14195, Germany
| | - Caroline Harnisch
- Institut für Chemie und Biochemie, RNA Biochemie, Freie Universität Berlin, Takustr. 6, Berlin 14195, Germany
| | - Kilian Merz
- Institut für Chemie und Biochemie, RNA Biochemie, Freie Universität Berlin, Takustr. 6, Berlin 14195, Germany
| | - Paula Leupold
- Institut für Chemie und Biochemie, RNA Biochemie, Freie Universität Berlin, Takustr. 6, Berlin 14195, Germany
| | - Peter Yudichev
- Institut für Chemie und Biochemie, RNA Biochemie, Freie Universität Berlin, Takustr. 6, Berlin 14195, Germany
| | - Dmitry E. Agafonov
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Cindy L. Will
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Cyrille Girard
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Christian Dienemann
- Department of Molecular Biology, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Henning Urlaub
- Research Group of Bioanalytical Mass Spectrometry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
- Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, Göttingen D-37075, Germany
| | - Berthold Kastner
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Florian Heyd
- Institut für Chemie und Biochemie, RNA Biochemie, Freie Universität Berlin, Takustr. 6, Berlin 14195, Germany
| | - Reinhard Lührmann
- Cellular Biochemistry, Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
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20
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Lipinski KA, Chi J, Chen X, Hoskins AA, Brow DA. Yeast U6 snRNA made by RNA polymerase II is less stable but functional. RNA (NEW YORK, N.Y.) 2022; 28:1606-1620. [PMID: 36195346 PMCID: PMC9670810 DOI: 10.1261/rna.079328.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
U6 small nuclear (sn)RNA is the shortest and most conserved snRNA in the spliceosome and forms a substantial portion of its active site. Unlike the other four spliceosomal snRNAs, which are synthesized by RNA polymerase (RNAP) II, U6 is made by RNAP III. To determine if some aspect of U6 function is incompatible with synthesis by RNAP II, we created a U6 snRNA gene with RNAP II promoter and terminator sequences. This "U6-II" gene is functional as the sole source of U6 snRNA in yeast, but its transcript is much less stable than U6 snRNA made by RNAP III. Addition of the U4 snRNA Sm protein binding site to U6-II increased its stability and led to formation of U6-II•Sm complexes. We conclude that synthesis of U6 snRNA by RNAP III is not required for its function and that U6 snRNPs containing the Sm complex can form in vivo. The ability to synthesize U6 snRNA with RNAP II relaxes sequence restraints imposed by intragenic RNAP III promoter and terminator elements and allows facile control of U6 levels via regulators of RNAP II transcription.
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Affiliation(s)
- Karli A Lipinski
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Jing Chi
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
| | - Xin Chen
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Aaron A Hoskins
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - David A Brow
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
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21
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Cartwright-Acar CH, Osterhoudt K, Suzuki JMNGL, Gomez D, Katzman S, Zahler AM. A forward genetic screen in C. elegans identifies conserved residues of spliceosomal proteins PRP8 and SNRNP200/BRR2 with a role in maintaining 5' splice site identity. Nucleic Acids Res 2022; 50:11834-11857. [PMID: 36321655 PMCID: PMC9723624 DOI: 10.1093/nar/gkac991] [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: 11/24/2021] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 11/07/2022] Open
Abstract
The spliceosome undergoes extensive rearrangements as it assembles onto precursor messenger RNAs. In the earliest assembly step, U1snRNA identifies the 5' splice site. However, U1snRNA leaves the spliceosome relatively early in assembly, and 5' splice site identity is subsequently maintained through interactions with U6snRNA, protein factor PRP8, and other components during the rearrangements that build the catalytic site. Using a forward genetic screen in Caenorhabditis elegans, we have identified suppressors of a locomotion defect caused by a 5'ss mutation. Here we report three new suppressor alleles from this screen, two in PRP8 and one in SNRNP200/BRR2. mRNASeq studies of these suppressor strains indicate that they also affect specific native alternative 5'ss, especially for suppressor PRP8 D1549N. A strong suppressor at the unstructured N-terminus of SNRNP200, N18K, indicates a novel role for this region. By examining distinct changes in the splicing of native genes, examining double mutants between suppressors, comparing these new suppressors to previously identified splicing suppressors from yeast, and mapping conserved suppressor residues onto cryoEM structural models of assembling human spliceosomes, we conclude that there are multiple interactions at multiple stages in spliceosome assembly responsible for maintaining the initial 5'ss identified by U1snRNA for entry into the catalytic core.
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Affiliation(s)
- Catiana H Cartwright-Acar
- Department of MCD Biology and The Center for Molecular Biology of RNA, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Kenneth Osterhoudt
- Department of MCD Biology and The Center for Molecular Biology of RNA, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Jessie M N G L Suzuki
- Department of MCD Biology and The Center for Molecular Biology of RNA, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Destiny R Gomez
- Department of MCD Biology and The Center for Molecular Biology of RNA, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Sol Katzman
- Genomics Institute, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Alan M Zahler
- Department of MCD Biology and The Center for Molecular Biology of RNA, University of California Santa Cruz, Santa Cruz, CA 95060, USA
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22
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Preussner M, Santos KF, Alles J, Heroven C, Heyd F, Wahl MC, Weber G. Structural and functional investigation of the human snRNP assembly factor AAR2 in complex with the RNase H-like domain of PRPF8. ACTA CRYSTALLOGRAPHICA SECTION D STRUCTURAL BIOLOGY 2022; 78:1373-1383. [PMID: 36322420 PMCID: PMC9629490 DOI: 10.1107/s2059798322009755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 10/05/2022] [Indexed: 11/07/2022]
Abstract
The crystal structure of human AAR2 bound to the central spliceosomal factor PRPF8 and in vitro functional data yield insights into the structural basis of snRNP assembly in humans. Small nuclear ribonucleoprotein complexes (snRNPs) represent the main subunits of the spliceosome. While the assembly of the snRNP core particles has been well characterized, comparably little is known of the incorporation of snRNP-specific proteins and the mechanisms of snRNP recycling. U5 snRNP assembly in yeast requires binding of the the Aar2 protein to Prp8p as a placeholder to preclude premature assembly of the SNRNP200 helicase, but the role of the human AAR2 homolog has not yet been investigated in detail. Here, a crystal structure of human AAR2 in complex with the RNase H-like domain of the U5-specific PRPF8 (PRP8F RH) is reported, revealing a significantly different interaction between the two proteins compared with that in yeast. Based on the structure of the AAR2–PRPF8 RH complex, the importance of the interacting regions and residues was probed and AAR2 variants were designed that failed to stably bind PRPF8 in vitro. Protein-interaction studies of AAR2 with U5 proteins using size-exclusion chromatography reveal similarities and marked differences in the interaction patterns compared with yeast Aar2p and imply phosphorylation-dependent regulation of AAR2 reminiscent of that in yeast. It is found that in vitro AAR2 seems to lock PRPF8 RH in a conformation that is only compatible with the first transesterification step of the splicing reaction and blocks a conformational switch to the step 2-like, Mg2+-coordinated conformation that is likely during U5 snRNP biogenesis. These findings extend the picture of AAR2 PRP8 interaction from yeast to humans and indicate a function for AAR2 in the spliceosomal assembly process beyond its role as an SNRNP200 placeholder in yeast.
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23
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Nameki N, Takizawa M, Suzuki T, Tani S, Kobayashi N, Sakamoto T, Muto Y, Kuwasako K. Structural basis for the interaction between the first SURP domain of the SF3A1 subunit in U2 snRNP and the human splicing factor SF1. Protein Sci 2022; 31:e4437. [PMID: 36173164 PMCID: PMC9514218 DOI: 10.1002/pro.4437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/24/2022] [Accepted: 08/28/2022] [Indexed: 11/08/2022]
Abstract
SURP domains are exclusively found in splicing-related proteins in all eukaryotes. SF3A1, a component of the U2 snRNP, has two tandem SURP domains, SURP1, and SURP2. SURP2 is permanently associated with a specific short region of SF3A3 within the SF3A protein complex whereas, SURP1 binds to the splicing factor SF1 for recruitment of U2 snRNP to the early spliceosomal complex, from which SF1 is dissociated during complex conversion. Here, we determined the solution structure of the complex of SURP1 and the human SF1 fragment using nuclear magnetic resonance (NMR) methods. SURP1 adopts the canonical topology of α1-α2-310 -α3, in which α1 and α2 are connected by a single glycine residue in a particular backbone conformation, allowing the two α-helices to be fixed at an acute angle. A hydrophobic patch, which is part of the characteristic surface formed by α1 and α2, specifically contacts a hydrophobic cluster on a 16-residue α-helix of the SF1 fragment. Furthermore, whereas only hydrophobic interactions occurred between SURP2 and the SF3A3 fragment, several salt bridges and hydrogen bonds were found between the residues of SURP1 and the SF1 fragment. This finding was confirmed through mutational studies using bio-layer interferometry. The study also revealed that the dissociation constant between SURP1 and the SF1 fragment peptide was approximately 20 μM, indicating a weak or transient interaction. Collectively, these results indicate that the interplay between U2 snRNP and SF1 involves a transient interaction of SURP1, and this transient interaction appears to be common to most SURP domains, except for SURP2.
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Affiliation(s)
- Nobukazu Nameki
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma, Japan
| | - Masayuki Takizawa
- Faculty of Pharmacy and Research Institute of Pharmaceutical Sciences, Musashino University, Nishitokyo, Tokyo, Japan
| | - Takayuki Suzuki
- Faculty of Pharmacy and Research Institute of Pharmaceutical Sciences, Musashino University, Nishitokyo, Tokyo, Japan
| | - Shoko Tani
- Faculty of Pharmacy and Research Institute of Pharmaceutical Sciences, Musashino University, Nishitokyo, Tokyo, Japan
| | - Naohiro Kobayashi
- RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa, Japan
| | - Taiichi Sakamoto
- Department of Life Science, Faculty of Advanced Engineering, Chiba Institute of Technology, Narashino, Chiba, Japan
| | - Yutaka Muto
- Faculty of Pharmacy and Research Institute of Pharmaceutical Sciences, Musashino University, Nishitokyo, Tokyo, Japan
| | - Kanako Kuwasako
- Faculty of Pharmacy and Research Institute of Pharmaceutical Sciences, Musashino University, Nishitokyo, Tokyo, Japan
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24
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Hluchý M, Gajdušková P, Ruiz de Los Mozos I, Rájecký M, Kluge M, Berger BT, Slabá Z, Potěšil D, Weiß E, Ule J, Zdráhal Z, Knapp S, Paruch K, Friedel CC, Blazek D. CDK11 regulates pre-mRNA splicing by phosphorylation of SF3B1. Nature 2022; 609:829-834. [PMID: 36104565 DOI: 10.1038/s41586-022-05204-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 08/08/2022] [Indexed: 11/09/2022]
Abstract
RNA splicing, the process of intron removal from pre-mRNA, is essential for the regulation of gene expression. It is controlled by the spliceosome, a megadalton RNA-protein complex that assembles de novo on each pre-mRNA intron through an ordered assembly of intermediate complexes1,2. Spliceosome activation is a major control step that requires substantial protein and RNA rearrangements leading to a catalytically active complex1-5. Splicing factor 3B subunit 1 (SF3B1) protein-a subunit of the U2 small nuclear ribonucleoprotein6-is phosphorylated during spliceosome activation7-10, but the kinase that is responsible has not been identified. Here we show that cyclin-dependent kinase 11 (CDK11) associates with SF3B1 and phosphorylates threonine residues at its N terminus during spliceosome activation. The phosphorylation is important for the association between SF3B1 and U5 and U6 snRNAs in the activated spliceosome, termed the Bact complex, and the phosphorylation can be blocked by OTS964, a potent and selective inhibitor of CDK11. Inhibition of CDK11 prevents spliceosomal transition from the precatalytic complex B to the activated complex Bact and leads to widespread intron retention and accumulation of non-functional spliceosomes on pre-mRNAs and chromatin. We demonstrate a central role of CDK11 in spliceosome assembly and splicing regulation and characterize OTS964 as a highly selective CDK11 inhibitor that suppresses spliceosome activation and splicing.
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Affiliation(s)
- Milan Hluchý
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Pavla Gajdušková
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Igor Ruiz de Los Mozos
- The Francis Crick Institute, London, UK
- Department of Personalized Medicine, NASERTIC, Government of Navarra, Pamplona, Spain
- Center for Applied Medical Research, University of Navarra, Pamplona, Spain
| | - Michal Rájecký
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Michael Kluge
- Institut für Informatik, Ludwig-Maximilians-Universität München, München, Germany
| | - Benedict-Tilman Berger
- Structural Genomics Consortium (SGC), Buchmann Institute for Life Sciences (BMLS), Goethe University Frankfurt am Main, Frankfurt am Main, Germany
- Institut für Pharmazeutische Chemie, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Zuzana Slabá
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - David Potěšil
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Elena Weiß
- Institut für Informatik, Ludwig-Maximilians-Universität München, München, Germany
| | - Jernej Ule
- The Francis Crick Institute, London, UK
- UK Dementia Research Institute, King's College London, London, UK
| | - Zbyněk Zdráhal
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Stefan Knapp
- Structural Genomics Consortium (SGC), Buchmann Institute for Life Sciences (BMLS), Goethe University Frankfurt am Main, Frankfurt am Main, Germany
- Institut für Pharmazeutische Chemie, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Kamil Paruch
- Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
- International Clinical Research Center, St Anne's University Hospital in Brno, Brno, Czech Republic
| | - Caroline C Friedel
- Institut für Informatik, Ludwig-Maximilians-Universität München, München, Germany
| | - Dalibor Blazek
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic.
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25
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Cytogenetic and Genetic Abnormalities with Diagnostic Value in Myelodysplastic Syndromes (MDS): Focus on the Pre-Messenger RNA Splicing Process. Diagnostics (Basel) 2022; 12:diagnostics12071658. [PMID: 35885562 PMCID: PMC9320363 DOI: 10.3390/diagnostics12071658] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 12/19/2022] Open
Abstract
Myelodysplastic syndromes (MDS) are considered to be diseases associated with splicing defects. A large number of genes involved in the pre-messenger RNA splicing process are mutated in MDS. Deletion of 5q and 7q are of diagnostic value, and those chromosome regions bear the numbers of splicing genes potentially deleted in del(5q) and del(7q)/-7 MDS. In this review, we present the splicing genes already known or suspected to be implicated in MDS pathogenesis. First, we focus on the splicing genes located on chromosome 5 (HNRNPA0, RBM27, RBM22, SLU7, DDX41), chromosome 7 (LUC7L2), and on the SF3B1 gene since both chromosome aberrations and the SF3B1 mutation are the only genetic abnormalities in splicing genes with clear diagnostic values. Then, we present and discuss other splicing genes that are showing a prognostic interest (SRSF2, U2AF1, ZRSR2, U2AF2, and PRPF8). Finally, we discuss the haploinsufficiency of splicing genes, especially from chromosomes 5 and 7, the important amplifier process of splicing defects, and the cumulative and synergistic effect of splicing genes defects in the MDS pathogenesis. At the time, when many authors suggest including the sequencing of some splicing genes to improve the diagnosis and the prognosis of MDS, a better understanding of these cooperative defects is needed.
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26
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Kumar J, Lackey L, Waldern JM, Dey A, Mustoe AM, Weeks KM, Mathews DH, Laederach A. Quantitative prediction of variant effects on alternative splicing in MAPT using endogenous pre-messenger RNA structure probing. eLife 2022; 11:73888. [PMID: 35695373 PMCID: PMC9236610 DOI: 10.7554/elife.73888] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 06/12/2022] [Indexed: 11/29/2022] Open
Abstract
Splicing is highly regulated and is modulated by numerous factors. Quantitative predictions for how a mutation will affect precursor mRNA (pre-mRNA) structure and downstream function are particularly challenging. Here, we use a novel chemical probing strategy to visualize endogenous precursor and mature MAPT mRNA structures in cells. We used these data to estimate Boltzmann suboptimal structural ensembles, which were then analyzed to predict consequences of mutations on pre-mRNA structure. Further analysis of recent cryo-EM structures of the spliceosome at different stages of the splicing cycle revealed that the footprint of the Bact complex with pre-mRNA best predicted alternative splicing outcomes for exon 10 inclusion of the alternatively spliced MAPT gene, achieving 74% accuracy. We further developed a β-regression weighting framework that incorporates splice site strength, RNA structure, and exonic/intronic splicing regulatory elements capable of predicting, with 90% accuracy, the effects of 47 known and 6 newly discovered mutations on inclusion of exon 10 of MAPT. This combined experimental and computational framework represents a path forward for accurate prediction of splicing-related disease-causing variants.
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Affiliation(s)
- Jayashree Kumar
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Lela Lackey
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Department of Genetics and Biochemistry, Center for Human Genetics, Clemson University, Greenwood, United States
| | - Justin M Waldern
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Abhishek Dey
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Anthony M Mustoe
- Verna and Marrs McClean Department of Biochemistry and Molecular Biology, Therapeutic Innovation Center (THINC), and Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Kevin M Weeks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - David H Mathews
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, United States
| | - Alain Laederach
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States
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27
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Neuhaus D. Zinc finger structure determination by NMR: Why zinc fingers can be a handful. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 130-131:62-105. [PMID: 36113918 PMCID: PMC7614390 DOI: 10.1016/j.pnmrs.2022.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/09/2022] [Accepted: 07/10/2022] [Indexed: 06/07/2023]
Abstract
Zinc fingers can be loosely defined as protein domains containing one or more tetrahedrally-co-ordinated zinc ions whose role is to stabilise the structure rather than to be involved in enzymatic chemistry; such zinc ions are often referred to as "structural zincs". Although structural zincs can occur in proteins of any size, they assume particular significance for very small protein domains, where they are often essential for maintaining a folded state. Such small structures, that sometimes have only marginal stability, can present particular difficulties in terms of sample preparation, handling and structure determination, and early on they gained a reputation for being resistant to crystallisation. As a result, NMR has played a more prominent role in structural studies of zinc finger proteins than it has for many other types of proteins. This review will present an overview of the particular issues that arise for structure determination of zinc fingers by NMR, and ways in which these may be addressed.
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Affiliation(s)
- David Neuhaus
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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28
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Sarnowski CP, Bikaki M, Leitner A. Cross-linking and mass spectrometry as a tool for studying the structural biology of ribonucleoproteins. Structure 2022; 30:441-461. [PMID: 35366400 DOI: 10.1016/j.str.2022.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 02/03/2022] [Accepted: 03/01/2022] [Indexed: 11/17/2022]
Abstract
Cross-linking and mass spectrometry (XL-MS) workflows represent an increasingly popular technique for low-resolution structural studies of macromolecular complexes. Cross-linking reactions take place in the solution state, capturing contact sites between components of a complex that represent the native, functionally relevant structure. Protein-protein XL-MS protocols are widely adopted, providing precise localization of cross-linking sites to single amino acid positions within a pair of cross-linked peptides. In contrast, protein-RNA XL-MS workflows are evolving rapidly and differ in their ability to localize interaction regions within the RNA sequence. Here, we review protein-protein and protein-RNA XL-MS workflows, and discuss their applications in studies of protein-RNA complexes. The examples highlight the complementary value of XL-MS in structural studies of protein-RNA complexes, where more established high-resolution techniques might be unable to produce conclusive data.
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Affiliation(s)
- Chris P Sarnowski
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, 8093 Zurich, Switzerland; Systems Biology PhD Program, University of Zürich and ETH Zürich, Zurich, Switzerland
| | - Maria Bikaki
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, 8093 Zurich, Switzerland
| | - Alexander Leitner
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, 8093 Zurich, Switzerland.
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29
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Bergfort A, Preußner M, Kuropka B, Ilik İA, Hilal T, Weber G, Freund C, Aktaş T, Heyd F, Wahl MC. A multi-factor trafficking site on the spliceosome remodeling enzyme BRR2 recruits C9ORF78 to regulate alternative splicing. Nat Commun 2022; 13:1132. [PMID: 35241646 PMCID: PMC8894380 DOI: 10.1038/s41467-022-28754-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 02/10/2022] [Indexed: 11/09/2022] Open
Abstract
The intrinsically unstructured C9ORF78 protein was detected in spliceosomes but its role in splicing is presently unclear. We find that C9ORF78 tightly interacts with the spliceosome remodeling factor, BRR2, in vitro. Affinity purification/mass spectrometry and RNA UV-crosslinking analyses identify additional C9ORF78 interactors in spliceosomes. Cryogenic electron microscopy structures reveal how C9ORF78 and the spliceosomal B complex protein, FBP21, wrap around the C-terminal helicase cassette of BRR2 in a mutually exclusive manner. Knock-down of C9ORF78 leads to alternative NAGNAG 3'-splice site usage and exon skipping, the latter dependent on BRR2. Inspection of spliceosome structures shows that C9ORF78 could contact several detected spliceosome interactors when bound to BRR2, including the suggested 3'-splice site regulating helicase, PRPF22. Together, our data establish C9ORF78 as a late-stage splicing regulatory protein that takes advantage of a multi-factor trafficking site on BRR2, providing one explanation for suggested roles of BRR2 during splicing catalysis and alternative splicing.
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Affiliation(s)
- Alexandra Bergfort
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Berlin, Germany.,Yale University, Molecular Biophysics and Biochemistry, New Haven, CT, USA
| | - Marco Preußner
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Berlin, Germany
| | - Benno Kuropka
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Protein Biochemistry, Berlin, Germany.,Freie Universität Berlin, Institute of Chemistry and Biochemistry, Core Facility BioSupraMol, Berlin, Germany
| | | | - Tarek Hilal
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Berlin, Germany.,Freie Universität Berlin, Institute of Chemistry and Biochemistry, Core Facility BioSupraMol, Berlin, Germany.,Freie Universität Berlin, Institute of Chemistry and Biochemistry, Research Center of Electron Microscopy and Core Facility BioSupraMol, Berlin, Germany
| | - Gert Weber
- Helmholtz-Zentrum Berlin für Materialien und Energie, Macromolecular Crystallography, Berlin, Germany
| | - Christian Freund
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Protein Biochemistry, Berlin, Germany
| | - Tuğçe Aktaş
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Florian Heyd
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Berlin, Germany
| | - Markus C Wahl
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Berlin, Germany. .,Helmholtz-Zentrum Berlin für Materialien und Energie, Macromolecular Crystallography, Berlin, Germany.
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Idrissou M, Maréchal A. The PRP19 Ubiquitin Ligase, Standing at the Cross-Roads of mRNA Processing and Genome Stability. Cancers (Basel) 2022; 14:878. [PMID: 35205626 PMCID: PMC8869861 DOI: 10.3390/cancers14040878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/01/2022] [Accepted: 02/04/2022] [Indexed: 12/07/2022] Open
Abstract
mRNA processing factors are increasingly being recognized as important regulators of genome stability. By preventing and resolving RNA:DNA hybrids that form co-transcriptionally, these proteins help avoid replication-transcription conflicts and thus contribute to genome stability through their normal function in RNA maturation. Some of these factors also have direct roles in the activation of the DNA damage response and in DNA repair. One of the most intriguing cases is that of PRP19, an evolutionarily conserved essential E3 ubiquitin ligase that promotes mRNA splicing, but also participates directly in ATR activation, double-strand break resection and mitosis. Here, we review historical and recent work on PRP19 and its associated proteins, highlighting their multifarious cellular functions as central regulators of spliceosome activity, R-loop homeostasis, DNA damage signaling and repair and cell division. Finally, we discuss open questions that are bound to shed further light on the functions of PRP19-containing complexes in both normal and cancer cells.
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Affiliation(s)
- Mouhamed Idrissou
- Faculty of Sciences, Department of Biology, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada;
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC J1H 5N3, Canada
| | - Alexandre Maréchal
- Faculty of Sciences, Department of Biology, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada;
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC J1H 5N3, Canada
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31
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A genetic screen in C. elegans reveals roles for KIN17 and PRCC in maintaining 5' splice site identity. PLoS Genet 2022; 18:e1010028. [PMID: 35143478 PMCID: PMC8865678 DOI: 10.1371/journal.pgen.1010028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 02/23/2022] [Accepted: 01/10/2022] [Indexed: 01/11/2023] Open
Abstract
Pre-mRNA splicing is an essential step of eukaryotic gene expression carried out by a series of dynamic macromolecular protein/RNA complexes, known collectively and individually as the spliceosome. This series of spliceosomal complexes define, assemble on, and catalyze the removal of introns. Molecular model snapshots of intermediates in the process have been created from cryo-EM data, however, many aspects of the dynamic changes that occur in the spliceosome are not fully understood. Caenorhabditis elegans follow the GU-AG rule of splicing, with almost all introns beginning with 5’ GU and ending with 3’ AG. These splice sites are identified early in the splicing cycle, but as the cycle progresses and “custody” of the pre-mRNA splice sites is passed from factor to factor as the catalytic site is built, the mechanism by which splice site identity is maintained or re-established through these dynamic changes is unclear. We performed a genetic screen in C. elegans for factors that are capable of changing 5’ splice site choice. We report that KIN17 and PRCC are involved in splice site choice, the first functional splicing role proposed for either of these proteins. Previously identified suppressors of cryptic 5’ splicing promote distal cryptic GU splice sites, however, mutations in KIN17 and PRCC instead promote usage of an unusual proximal 5’ splice site which defines an intron beginning with UU, separated by 1nt from a GU donor. We performed high-throughput mRNA sequencing analysis and found that mutations in PRCC, and to a lesser extent KIN17, changed alternative 5’ splice site usage at native sites genome-wide, often promoting usage of nearby non-consensus sites. Our work has uncovered both fine and coarse mechanisms by which the spliceosome maintains splice site identity during the complex assembly process. Pre-messenger RNA splicing is an important regulator of eukaryotic gene expression, changing the content, frame, and functionality of both coding and non-coding transcripts. Our understanding of how the spliceosome chooses where to cut has focused on the initial identification of splice sites. However, our results suggest that the spliceosome also relies on other components in later steps to maintain the identity of the splice donor sites. We are currently in the midst of a “resolution revolution”, with ever-clearer cryo-EM snapshots of stalled complexes, allowing researchers to visualize moments in time in the splicing cycle. These models are illuminating, but do not always elucidate mechanistic functioning of a highly dynamic ribonucleoprotein complex. Therefore, our lab takes a complementary approach, using the power of genetics in a multicellular animal to gain functional insights into the spliceosome. Using a C.elegans genetic screen, we have found novel functional splicing roles for two proteins, KIN17 and PRCC. Mutations in PRCC in particular promote nearby alternative 5’ splice sites at native loci. This work improves our understanding of how the spliceosome maintains the identity of where to cut the pre-mRNA, and thus how genes are expressed and used in multicellular animals.
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El Fatimy R, Zhang Y, Deforzh E, Ramadas M, Saravanan H, Wei Z, Rabinovsky R, Teplyuk NM, Uhlmann EJ, Krichevsky AM. A nuclear function for an oncogenic microRNA as a modulator of snRNA and splicing. Mol Cancer 2022; 21:17. [PMID: 35033060 PMCID: PMC8760648 DOI: 10.1186/s12943-022-01494-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/23/2021] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND miRNAs are regulatory transcripts established as repressors of mRNA stability and translation that have been functionally implicated in carcinogenesis. miR-10b is one of the key onco-miRs associated with multiple forms of cancer. Malignant gliomas exhibit particularly striking dependence on miR-10b. However, despite the therapeutic potential of miR-10b targeting, this miRNA's poorly investigated and largely unconventional properties hamper the clinical translation. METHODS We utilized Covalent Ligation of Endogenous Argonaute-bound RNAs and their high-throughput RNA sequencing to identify miR-10b interactome and a combination of biochemical and imaging approaches for target validation. They included Crosslinking and RNA immunoprecipitation with spliceosomal proteins, a combination of miRNA FISH with protein immunofluorescence in glioma cells and patient-derived tumors, native Northern blotting, and the transcriptome-wide analysis of alternative splicing. RESULTS We demonstrate that miR-10b binds to U6 snRNA, a core component of the spliceosomal machinery. We provide evidence of the direct binding between miR-10b and U6, in situ imaging of miR-10b and U6 co-localization in glioma cells and tumors, and biochemical co-isolation of miR-10b with the components of the spliceosome. We further demonstrate that miR-10b modulates U6 N-6-adenosine methylation and pseudouridylation, U6 binding to splicing factors SART3 and PRPF8, and regulates U6 stability, conformation, and levels. These effects on U6 result in global splicing alterations, exemplified by the altered ratio of the isoforms of a small GTPase CDC42, reduced overall CDC42 levels, and downstream CDC42 -mediated effects on cell viability. CONCLUSIONS We identified U6 snRNA, the key RNA component of the spliceosome, as the top miR-10b target in glioblastoma. We, therefore, present an unexpected intersection of the miRNA and splicing machineries and a new nuclear function for a major cancer-associated miRNA.
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Affiliation(s)
- Rachid El Fatimy
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, 60 Fenwood Rd, Room 9002T, Boston, MA, 02115, USA
- Current Address: Institute of Biological Sciences (ISSB-P), Mohammed VI Polytechnic University (UM6P), 43150, Benguerir, Morocco
| | - Yanhong Zhang
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, 60 Fenwood Rd, Room 9002T, Boston, MA, 02115, USA
| | - Evgeny Deforzh
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, 60 Fenwood Rd, Room 9002T, Boston, MA, 02115, USA
| | - Mahalakshmi Ramadas
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, 60 Fenwood Rd, Room 9002T, Boston, MA, 02115, USA
| | - Harini Saravanan
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, 60 Fenwood Rd, Room 9002T, Boston, MA, 02115, USA
| | - Zhiyun Wei
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, 60 Fenwood Rd, Room 9002T, Boston, MA, 02115, USA
- Current Address: Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai, 200092, China
| | - Rosalia Rabinovsky
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, 60 Fenwood Rd, Room 9002T, Boston, MA, 02115, USA
| | - Nadiya M Teplyuk
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, 60 Fenwood Rd, Room 9002T, Boston, MA, 02115, USA
| | - Erik J Uhlmann
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, 60 Fenwood Rd, Room 9002T, Boston, MA, 02115, USA
| | - Anna M Krichevsky
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, 60 Fenwood Rd, Room 9002T, Boston, MA, 02115, USA.
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Jobbins AM, Campagne S, Weinmeister R, Lucas CM, Gosliga AR, Clery A, Chen L, Eperon LP, Hodson MJ, Hudson AJ, Allain FHT, Eperon IC. Exon-independent recruitment of SRSF1 is mediated by U1 snRNP stem-loop 3. EMBO J 2022; 41:e107640. [PMID: 34779515 PMCID: PMC8724738 DOI: 10.15252/embj.2021107640] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 10/04/2021] [Accepted: 10/07/2021] [Indexed: 12/11/2022] Open
Abstract
SRSF1 protein and U1 snRNPs are closely connected splicing factors. They both stimulate exon inclusion, SRSF1 by binding to exonic splicing enhancer sequences (ESEs) and U1 snRNPs by binding to the downstream 5' splice site (SS), and both factors affect 5' SS selection. The binding of U1 snRNPs initiates spliceosome assembly, but SR proteins such as SRSF1 can in some cases substitute for it. The mechanistic basis of this relationship is poorly understood. We show here by single-molecule methods that a single molecule of SRSF1 can be recruited by a U1 snRNP. This reaction is independent of exon sequences and separate from the U1-independent process of binding to an ESE. Structural analysis and cross-linking data show that SRSF1 contacts U1 snRNA stem-loop 3, which is required for splicing. We suggest that the recruitment of SRSF1 to a U1 snRNP at a 5'SS is the basis for exon definition by U1 snRNP and might be one of the principal functions of U1 snRNPs in the core reactions of splicing in mammals.
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Affiliation(s)
- Andrew M Jobbins
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Present address:
MRC London Institute of Medical SciencesLondonUK
- Present address:
Institute of Clinical SciencesImperial College LondonLondonUK
| | - Sébastien Campagne
- Institute of BiochemistryETH ZürichSwitzerland
- Present address:
Inserm U1212CNRS UMR5320ARNA LaboratoryBordeaux CedexFrance
| | - Robert Weinmeister
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Leicester Institute of Structural & Chemical Biology and Department of ChemistryUniversity of LeicesterLeicesterUK
| | - Christian M Lucas
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Alison R Gosliga
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Present address:
Institut für Industrielle GenetikAbt.(eilung) SystembiologieUniversität StuttgartStuttgartGermany
| | | | - Li Chen
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Lucy P Eperon
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Mark J Hodson
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Andrew J Hudson
- Leicester Institute of Structural & Chemical Biology and Department of ChemistryUniversity of LeicesterLeicesterUK
| | | | - Ian C Eperon
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
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Graziadei A, Rappsilber J. Leveraging crosslinking mass spectrometry in structural and cell biology. Structure 2021; 30:37-54. [PMID: 34895473 DOI: 10.1016/j.str.2021.11.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/11/2021] [Accepted: 11/17/2021] [Indexed: 12/18/2022]
Abstract
Crosslinking mass spectrometry (crosslinking-MS) is a versatile tool providing structural insights into protein conformation and protein-protein interactions. Its medium-resolution residue-residue distance restraints have been used to validate protein structures proposed by other methods and have helped derive models of protein complexes by integrative structural biology approaches. The use of crosslinking-MS in integrative approaches is underpinned by progress in estimating error rates in crosslinking-MS data and in combining these data with other information. The flexible and high-throughput nature of crosslinking-MS has allowed it to complement the ongoing resolution revolution in electron microscopy by providing system-wide residue-residue distance restraints, especially for flexible regions or systems. Here, we review how crosslinking-MS information has been leveraged in structural model validation and integrative modeling. Crosslinking-MS has also been a key technology for cell biology studies and structural systems biology where, in conjunction with cryoelectron tomography, it can provide structural and mechanistic insights directly in situ.
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Affiliation(s)
- Andrea Graziadei
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany
| | - Juri Rappsilber
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany; Wellcome Centre for Cell Biology, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK.
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35
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Sales-Lee J, Perry DS, Bowser BA, Diedrich JK, Rao B, Beusch I, Yates JR, Roy SW, Madhani HD. Coupling of spliceosome complexity to intron diversity. Curr Biol 2021; 31:4898-4910.e4. [PMID: 34555349 DOI: 10.1016/j.cub.2021.09.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 08/17/2021] [Accepted: 09/01/2021] [Indexed: 10/20/2022]
Abstract
We determined that over 40 spliceosomal proteins are conserved between many fungal species and humans but were lost during the evolution of S. cerevisiae, an intron-poor yeast with unusually rigid splicing signals. We analyzed null mutations in a subset of these factors, most of which had not been investigated previously, in the intron-rich yeast Cryptococcus neoformans. We found they govern splicing efficiency of introns with divergent spacing between intron elements. Importantly, most of these factors also suppress usage of weak nearby cryptic/alternative splice sites. Among these, orthologs of GPATCH1 and the helicase DHX35 display correlated functional signatures and copurify with each other as well as components of catalytically active spliceosomes, identifying a conserved G patch/helicase pair that promotes splicing fidelity. We propose that a significant fraction of spliceosomal proteins in humans and most eukaryotes are involved in limiting splicing errors, potentially through kinetic proofreading mechanisms, thereby enabling greater intron diversity.
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Affiliation(s)
- Jade Sales-Lee
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Daniela S Perry
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Bradley A Bowser
- Department of Molecular and Cellular Biology, University of California, Merced, Merced, CA 95343, USA
| | - Jolene K Diedrich
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Beiduo Rao
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Irene Beusch
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - John R Yates
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Scott W Roy
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA.
| | - Hiten D Madhani
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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Urabe VK, Stevers M, Ghosh AK, Jurica MS. U2 snRNA structure is influenced by SF3A and SF3B proteins but not by SF3B inhibitors. PLoS One 2021; 16:e0258551. [PMID: 34648557 PMCID: PMC8516221 DOI: 10.1371/journal.pone.0258551] [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: 07/14/2021] [Accepted: 09/29/2021] [Indexed: 11/19/2022] Open
Abstract
U2 snRNP is an essential component of the spliceosome. It is responsible for branch point recognition in the spliceosome A-complex via base-pairing of U2 snRNA with an intron to form the branch helix. Small molecule inhibitors target the SF3B component of the U2 snRNP and interfere with A-complex formation during spliceosome assembly. We previously found that the first SF3B inhibited-complex is less stable than A-complex and hypothesized that SF3B inhibitors interfere with U2 snRNA secondary structure changes required to form the branch helix. Using RNA chemical modifiers, we probed U2 snRNA structure in A-complex and SF3B inhibited splicing complexes. The reactivity pattern for U2 snRNA in the SF3B inhibited-complex is indistinguishable from that of A-complex, suggesting that they have the same secondary structure conformation, including the branch helix. This observation suggests SF3B inhibited-complex instability does not stem from an alternate RNA conformation and instead points to the inhibitors interfering with protein component interactions that normally stabilize U2 snRNP’s association with an intron. In addition, we probed U2 snRNA in the free U2 snRNP in the presence of SF3B inhibitor and again saw no differences. However, increased protection of nucleotides upstream of Stem I in the absence of SF3A and SF3B proteins suggests a change of secondary structure at the very 5′ end of U2 snRNA. Chemical probing of synthetic U2 snRNA in the absence of proteins results in similar protections and predicts a previously uncharacterized extension of Stem I. Because this stem must be disrupted for SF3A and SF3B proteins to stably join the snRNP, the structure has the potential to influence snRNP assembly and recycling after spliceosome disassembly.
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Affiliation(s)
- Veronica K. Urabe
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, California, United States of America
| | - Meredith Stevers
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, California, United States of America
| | - Arun K. Ghosh
- Department of Chemistry and Department of Medicinal Chemistry, Purdue University, West Lafayette, Indiana, United States of America
| | - Melissa S. Jurica
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, California, United States of America
- Center for Molecular Biology of RNA, University of California, Santa Cruz, California, United States of America
- * E-mail:
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de Lourenço IO, Seixas FAV, Fernandez MA, Almeida FCL, Fossey MA, de Souza FP, Caruso ÍP. 1H, 15N, and 13C resonance assignments of the SH3-like tandem domain of human KIN protein. BIOMOLECULAR NMR ASSIGNMENTS 2021; 15:449-453. [PMID: 34417717 DOI: 10.1007/s12104-021-10044-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
KIN is a DNA/RNA-binding protein conserved evolutionarily from yeast to humans and expressed ubiquitously in mammals. It is an essential nuclear protein involved in numerous cellular processes, such as DNA replication, class-switch recombination, cell cycle regulation, and response to UV or ionizing radiation-induced DNA damage. The C-terminal region of the human KIN (hKIN) protein is composed of an SH3-like tandem domain, which is crucial for the anti-proliferation effect of the full-length protein. Herein, we present the 1H, 15N, and 13C resonances assignment of the backbone and side chains for the SH3-like tandem domain of the hKIN protein, as well as the secondary structure prediction based on the assigned chemical shifts using TALOS-N software. This work prepares the ground for future studies of RNA-binding and backbone dynamics.
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Affiliation(s)
- Isabella Otenio de Lourenço
- Department of Physics, Institute of Biosciences, Letters and Exact Sciences (IBILCE), Multiuser Center for Biomolecular Innovation (CMIB), São Paulo State University "Júlio de Mesquita Filho" (UNESP), São José do Rio Preto, SP, 15054-000, Brazil
| | | | - Maria Aparecida Fernandez
- Department of Biotechnology, Genetics and Cell Biology, Maringá State University (UEM), Maringá, PR, 87020-900, Brazil
| | - Fabio Ceneviva Lacerda Almeida
- Institute of Medical Biochemistry Leopoldo de Meis (IBqM) and National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, 21941-590, Brazil
| | - Marcelo Andrés Fossey
- Department of Physics, Institute of Biosciences, Letters and Exact Sciences (IBILCE), Multiuser Center for Biomolecular Innovation (CMIB), São Paulo State University "Júlio de Mesquita Filho" (UNESP), São José do Rio Preto, SP, 15054-000, Brazil
| | - Fátima Pereira de Souza
- Department of Physics, Institute of Biosciences, Letters and Exact Sciences (IBILCE), Multiuser Center for Biomolecular Innovation (CMIB), São Paulo State University "Júlio de Mesquita Filho" (UNESP), São José do Rio Preto, SP, 15054-000, Brazil
| | - Ícaro Putinhon Caruso
- Department of Physics, Institute of Biosciences, Letters and Exact Sciences (IBILCE), Multiuser Center for Biomolecular Innovation (CMIB), São Paulo State University "Júlio de Mesquita Filho" (UNESP), São José do Rio Preto, SP, 15054-000, Brazil.
- Institute of Medical Biochemistry Leopoldo de Meis (IBqM) and National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, 21941-590, Brazil.
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Chanarat S. UBL5/Hub1: An Atypical Ubiquitin-Like Protein with a Typical Role as a Stress-Responsive Regulator. Int J Mol Sci 2021; 22:ijms22179384. [PMID: 34502293 PMCID: PMC8431670 DOI: 10.3390/ijms22179384] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 08/25/2021] [Accepted: 08/29/2021] [Indexed: 11/23/2022] Open
Abstract
Members of the ubiquitin-like protein family are known for their ability to modify substrates by covalent conjugation. The highly conserved ubiquitin relative UBL5/Hub1, however, is atypical because it lacks a carboxy-terminal di-glycine motif required for conjugation, and the whole E1-E2-E3 enzyme cascade is likely absent. Though the conjugation-mediated role of UBL5/Hub1 is controversial, it undoubtedly functions by interacting non-covalently with its partners. Several interactors of UBL5/Hub1 identified to date have suggested broad stress-responsive functions of the protein, for example, stress-induced control of pre-mRNA splicing, Fanconi anemia pathway of DNA damage repair, and mitochondrial unfolded protein response. While having an atypical mode of function, UBL5/Hub1 is still a stress protein that regulates feedback to various stimuli in a similar manner to other ubiquitin-like proteins. In this review, I discuss recent progress in understanding the functions of UBL5/Hub1 and the fundamental questions which remain to be answered.
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Affiliation(s)
- Sittinan Chanarat
- Laboratory of Molecular Cell Biology, Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
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Bizarro J, Deryusheva S, Wacheul L, Gupta V, Ernst FGM, Lafontaine DLJ, Gall JG, Meier UT. Nopp140-chaperoned 2'-O-methylation of small nuclear RNAs in Cajal bodies ensures splicing fidelity. Genes Dev 2021; 35:1123-1141. [PMID: 34301768 PMCID: PMC8336889 DOI: 10.1101/gad.348660.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/29/2021] [Indexed: 12/27/2022]
Abstract
In this study, Bizarro et al. sought to understand the function and subcellular site of snRNA modification, and found that Cajal body (CB) localization of the protein Nopp140 is essential for concentration of small Cajal body-specific ribonucleoproteins (scaRNPs) in nuclear condensate and that phosphorylation by casein kinase 2 (CK2) at ∼80 serines targets Nopp140 to CBs. Nopp140 knockdown-mediated release of scaRNPs from CBs severely compromises 2′-O-methylation of spliceosomal snRNAs, identifying CBs as the site of scaRNP catalysis. Spliceosomal small nuclear RNAs (snRNAs) are modified by small Cajal body (CB)-specific ribonucleoproteins (scaRNPs) to ensure snRNP biogenesis and pre-mRNA splicing. However, the function and subcellular site of snRNA modification are largely unknown. We show that CB localization of the protein Nopp140 is essential for concentration of scaRNPs in that nuclear condensate; and that phosphorylation by casein kinase 2 (CK2) at ∼80 serines targets Nopp140 to CBs. Transiting through CBs, snRNAs are apparently modified by scaRNPs. Indeed, Nopp140 knockdown-mediated release of scaRNPs from CBs severely compromises 2′-O-methylation of spliceosomal snRNAs, identifying CBs as the site of scaRNP catalysis. Additionally, alternative splicing patterns change indicating that these modifications in U1, U2, U5, and U12 snRNAs safeguard splicing fidelity. Given the importance of CK2 in this pathway, compromised splicing could underlie the mode of action of small molecule CK2 inhibitors currently considered for therapy in cholangiocarcinoma, hematological malignancies, and COVID-19.
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Affiliation(s)
| | | | - Ludivine Wacheul
- RNA Molecular Biology, Fonds National de la Recherche Scientifique (FRS/FNRS), Université Libre de Bruxelles (ULB), B-6041 Gosselies, Belgium
| | - Varun Gupta
- Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Felix G M Ernst
- RNA Molecular Biology, Fonds National de la Recherche Scientifique (FRS/FNRS), Université Libre de Bruxelles (ULB), B-6041 Gosselies, Belgium
| | - Denis L J Lafontaine
- RNA Molecular Biology, Fonds National de la Recherche Scientifique (FRS/FNRS), Université Libre de Bruxelles (ULB), B-6041 Gosselies, Belgium
| | - Joseph G Gall
- Carnegie Institution for Science, Baltimore, Maryland 21218, USA
| | - U Thomas Meier
- Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Biology of the mRNA Splicing Machinery and Its Dysregulation in Cancer Providing Therapeutic Opportunities. Int J Mol Sci 2021; 22:ijms22105110. [PMID: 34065983 PMCID: PMC8150589 DOI: 10.3390/ijms22105110] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/07/2021] [Accepted: 05/07/2021] [Indexed: 12/13/2022] Open
Abstract
Dysregulation of messenger RNA (mRNA) processing—in particular mRNA splicing—is a hallmark of cancer. Compared to normal cells, cancer cells frequently present aberrant mRNA splicing, which promotes cancer progression and treatment resistance. This hallmark provides opportunities for developing new targeted cancer treatments. Splicing of precursor mRNA into mature mRNA is executed by a dynamic complex of proteins and small RNAs called the spliceosome. Spliceosomes are part of the supraspliceosome, a macromolecular structure where all co-transcriptional mRNA processing activities in the cell nucleus are coordinated. Here we review the biology of the mRNA splicing machinery in the context of other mRNA processing activities in the supraspliceosome and present current knowledge of its dysregulation in lung cancer. In addition, we review investigations to discover therapeutic targets in the spliceosome and give an overview of inhibitors and modulators of the mRNA splicing process identified so far. Together, this provides insight into the value of targeting the spliceosome as a possible new treatment for lung cancer.
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Bizarro J, Deryusheva S, Wacheul L, Gupta V, Ernst FGM, Lafontaine DLJ, Gall JG, Meier UT. Nopp140-chaperoned 2'-O-methylation of small nuclear RNAs in Cajal bodies ensures splicing fidelity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2021.04.29.441821. [PMID: 33948588 PMCID: PMC8095195 DOI: 10.1101/2021.04.29.441821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Spliceosomal small nuclear RNAs (snRNAs) are modified by small Cajal body (CB) specific ribonucleoproteins (scaRNPs) to ensure snRNP biogenesis and pre-mRNA splicing. However, the function and subcellular site of snRNA modification are largely unknown. We show that CB localization of the protein Nopp140 is essential for concentration of scaRNPs in that nuclear condensate; and that phosphorylation by casein kinase 2 (CK2) at some 80 serines targets Nopp140 to CBs. Transiting through CBs, snRNAs are apparently modified by scaRNPs. Indeed, Nopp140 knockdown-mediated release of scaRNPs from CBs severely compromises 2'-O-methylation of spliceosomal snRNAs, identifying CBs as the site of scaRNP catalysis. Additionally, alternative splicing patterns change indicating that these modifications in U1, U2, U5, and U12 snRNAs safeguard splicing fidelity. Given the importance of CK2 in this pathway, compromised splicing could underlie the mode of action of small molecule CK2 inhibitors currently considered for therapy in cholangiocarcinoma, hematological malignancies, and COVID-19.
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42
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van der Feltz C, Nikolai B, Schneider C, Paulson JC, Fu X, Hoskins AA. Saccharomyces cerevisiae Ecm2 Modulates the Catalytic Steps of pre-mRNA Splicing. RNA (NEW YORK, N.Y.) 2021; 27:rna.077727.120. [PMID: 33547186 PMCID: PMC8051269 DOI: 10.1261/rna.077727.120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 02/03/2021] [Indexed: 05/10/2023]
Abstract
Genetic, biochemical, and structural studies have elucidated the molecular basis for spliceosome catalysis. Splicing is RNA catalyzed and the essential snRNA and protein factors are well-conserved. However, little is known about how non-essential components of the spliceosome contribute to the reaction and modulate the activities of the fundamental core machinery. Ecm2 is a non-essential yeast splicing factor that is a member of the Prp19-related complex of proteins. Cryo-electron microscopy (cryo-EM) structures have revealed that Ecm2 binds the U6 snRNA and is entangled with Cwc2, a factor previously found to promote a catalytically active conformation of the spliceosome. These structures also indicate that Ecm2 and the U2 snRNA likely form a transient interaction during 5' splice site (SS) cleavage. We have characterized genetic interactions between ECM2 and alleles of splicing factors that alter the catalytic steps in splicing. In addition, we have studied how loss of ECM2 impacts splicing of pre-mRNAs containing non-consensus or competing SS. Our results show that ECM2 functions during the catalytic stages of splicing. Our data are consistent with Ecm2 facilitating the formation and stabilization of the 1st-step catalytic site, promoting 2nd-step catalysis, and permiting alternate 5' SS usage. We propose that Cwc2 and Ecm2 can each fine-tune the spliceosome active site in unique ways. Their interaction network may act as a conduit through which splicing of certain pre-mRNAs, such as those containing weak or alternate splice sites, can be regulated.
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Bai R, Wan R, Wang L, Xu K, Zhang Q, Lei J, Shi Y. Structure of the activated human minor spliceosome. Science 2021; 371:science.abg0879. [PMID: 33509932 DOI: 10.1126/science.abg0879] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 01/18/2021] [Indexed: 12/31/2022]
Abstract
The minor spliceosome mediates splicing of the rare but essential U12-type precursor messenger RNA. Here, we report the atomic features of the activated human minor spliceosome determined by cryo-electron microscopy at 2.9-angstrom resolution. The 5' splice site and branch point sequence of the U12-type intron are recognized by the U6atac and U12 small nuclear RNAs (snRNAs), respectively. Five newly identified proteins stabilize the conformation of the catalytic center: The zinc finger protein SCNM1 functionally mimics the SF3a complex of the major spliceosome, the RBM48-ARMC7 complex binds the γ-monomethyl phosphate cap at the 5' end of U6atac snRNA, the U-box protein PPIL2 coordinates loop I of U5 snRNA and stabilizes U5 small nuclear ribonucleoprotein (snRNP), and CRIPT stabilizes U12 snRNP. Our study provides a framework for the mechanistic understanding of the function of the human minor spliceosome.
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Affiliation(s)
- Rui Bai
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Xihu District, Hangzhou 310024, Zhejiang Province, China.,Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, Xihu District, Hangzhou 310024, Zhejiang Province, China
| | - Ruixue Wan
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Xihu District, Hangzhou 310024, Zhejiang Province, China. .,Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, Xihu District, Hangzhou 310024, Zhejiang Province, China
| | - Lin Wang
- Beijing Advanced Innovation Center for Structural Biology and Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Kui Xu
- Beijing Advanced Innovation Center for Structural Biology and Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qiangfeng Zhang
- Beijing Advanced Innovation Center for Structural Biology and Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianlin Lei
- Beijing Advanced Innovation Center for Structural Biology and Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.,Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yigong Shi
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Xihu District, Hangzhou 310024, Zhejiang Province, China. .,Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, Xihu District, Hangzhou 310024, Zhejiang Province, China.,Beijing Advanced Innovation Center for Structural Biology and Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
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