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Ma L, Zhang X, Li C, Ma X, Zhao X, Zhao X, Zhang P, Zhu X. A U2 snRNP-specific protein, U2A', is involved in stress response and drug resistance in Cryptococcus deneoformans. Biochimie 2024; 220:179-187. [PMID: 37806618 DOI: 10.1016/j.biochi.2023.10.005] [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: 03/14/2023] [Revised: 08/14/2023] [Accepted: 10/06/2023] [Indexed: 10/10/2023]
Abstract
The spliceosome, a large complex containing five conserved small ribonucleoprotein particles (snRNPs) U1, U2, U4, U5 and U6, plays important roles in precursor messenger RNA splicing. However, the function and mechanism of the spliceosomal snRNPs have not been thoroughly studied in the pathogenic yeast Cryptococcus deneoformans. In this study, we identified a U2A' homologous protein as a component of the cryptococcal U2 snRNP, which was encoded by the LEA1 gene. Using the "suicide" CRISPR-Cas9 tool, we deleted the LEA1 gene in C. deneoformans JEC21 strain and obtained the disruption mutant lea1Δ. The mutant showed a hypersensitivity to 0.03 % sodium dodecyl sulfate, as well as disordered chitin distribution in cell wall observed with Calcofluor White staining, which collectively illustrated the function of U2A' in maintenance of cell wall integrity. Further examination showed that lea1Δ displayed a decreased tolerance to lower or elevated temperatures, osmotic pressure and oxidative stress. The lea1Δ still exhibited susceptibility to geneticin and 5-flucytosine, and increased resistance to ketoconazole. Even, the mutant had a reduced capsule, and the virulence of lea1Δ in the Galleria mellonella model was decreased. Our results indicate that the U2A'-mediated RNA-processing has a particular role in the processing of gene products involved in response to stresses and virulence.
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Affiliation(s)
- Lan Ma
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Xueqing Zhang
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Chenxi Li
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Xiaoyu Ma
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Xuan Zhao
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Xueru Zhao
- Henan Provincial People's Hospital, Zhengzhou, 450003, China
| | - Ping Zhang
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China.
| | - Xudong Zhu
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, 100875, China.
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2
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Porat J, Slat VA, Rader SD, Bayfield MA. The fission yeast methyl phosphate capping enzyme Bmc1 guides 2'-O-methylation of the U6 snRNA. Nucleic Acids Res 2023; 51:8805-8819. [PMID: 37403782 PMCID: PMC10484740 DOI: 10.1093/nar/gkad563] [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: 04/29/2023] [Revised: 06/15/2023] [Accepted: 06/23/2023] [Indexed: 07/06/2023] Open
Abstract
Splicing requires the tight coordination of dynamic spliceosomal RNAs and proteins. U6 is the only spliceosomal RNA transcribed by RNA Polymerase III and undergoes an extensive maturation process. In humans and fission yeast, this includes addition of a 5' γ-monomethyl phosphate cap by members of the Bin3/MePCE family as well as snoRNA guided 2'-O-methylation. Previously, we have shown that the Bin3/MePCE homolog Bmc1 is recruited to the S. pombe telomerase holoenzyme by the LARP7 family protein Pof8, where it acts in a catalytic-independent manner to protect the telomerase RNA and facilitate holoenzyme assembly. Here, we show that Bmc1 and Pof8 are required for the formation of a distinct U6 snRNP that promotes 2'-O-methylation of U6, and identify a non-canonical snoRNA that guides this methylation. We also show that the 5' γ-monomethyl phosphate capping activity of Bmc1 is not required for its role in promoting snoRNA guided 2'-O-methylation, and that this role relies on different regions of Pof8 from those required for Pof8 function in telomerase. Our results are consistent with a novel role for Bmc1/MePCE family members in stimulating 2'-O-methylation and a more general role for Bmc1 and Pof8 in guiding noncoding RNP assembly beyond the telomerase RNP.
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Affiliation(s)
| | - Viktor A Slat
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Stephen D Rader
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
- Department of Chemistry and Biochemistry, University of Northern British Columbia, Prince George, Canada
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3
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Ding Z, Meng YR, Fan YJ, Xu YZ. Roles of minor spliceosome in intron recognition and the convergence with the better understood major spliceosome. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1761. [PMID: 36056453 DOI: 10.1002/wrna.1761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 06/06/2022] [Accepted: 08/06/2022] [Indexed: 01/31/2023]
Abstract
Catalyzed by spliceosomes in the nucleus, RNA splicing removes intronic sequences from precursor RNAs in eukaryotes to generate mature RNA, which also significantly increases proteome complexity and fine-tunes gene expression. Most metazoans have two coexisting spliceosomes; the major spliceosome, which removes >99.5% of introns, and the minor spliceosome, which removes far fewer introns (only 770 at present have been predicted in the human genome). Both spliceosomes are large and dynamic machineries, each consisting of five small nuclear RNAs (snRNAs) and more than 100 proteins. However, the dynamic assembly, catalysis, and protein composition of the minor spliceosome are still poorly understood. With different splicing signals, minor introns are rare and usually distributed alone and flanked by major introns in genes, raising questions of how they are recognized by the minor spliceosome and how their processing deals with the splicing of neighboring major introns. Due to large numbers of introns and close similarities between the two machinery, cooperative, and competitive recognition by the two spliceosomes has been investigated. Functionally, many minor-intron-containing genes are evolutionarily conserved and essential. Mutations in the minor spliceosome exhibit a variety of developmental defects in plants and animals and are linked to numerous human diseases. Here, we review recent progress in the understanding of minor splicing, compare currently known components of the two spliceosomes, survey minor introns in a wide range of organisms, discuss cooperation and competition of the two spliceosomes in splicing of minor-intron-containing genes, and contributions of minor splicing mutations in development and diseases. This article is categorized under: RNA Processing > Processing of Small RNAs RNA Processing > Splicing Mechanisms RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry.
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Affiliation(s)
- Zhan Ding
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China.,Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yan-Ran Meng
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China
| | - Yu-Jie Fan
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China
| | - Yong-Zhen Xu
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China
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4
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Anil AT, Choudhary K, Pandian R, Gupta P, Thakran P, Singh A, Sharma M, Mishra SK. Splicing of branchpoint-distant exons is promoted by Cactin, Tls1 and the ubiquitin-fold-activated Sde2. Nucleic Acids Res 2022; 50:10000-10014. [PMID: 36095128 PMCID: PMC9508853 DOI: 10.1093/nar/gkac769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/22/2022] [Accepted: 08/27/2022] [Indexed: 11/13/2022] Open
Abstract
Intron diversity facilitates regulated gene expression and alternative splicing. Spliceosomes excise introns after recognizing their splicing signals: the 5'-splice site (5'ss), branchpoint (BP) and 3'-splice site (3'ss). The latter two signals are recognized by U2 small nuclear ribonucleoprotein (snRNP) and its accessory factors (U2AFs), but longer spacings between them result in weaker splicing. Here, we show that excision of introns with a BP-distant 3'ss (e.g. rap1 intron 2) requires the ubiquitin-fold-activated splicing regulator Sde2 in Schizosaccharomyces pombe. By monitoring splicing-specific ura4 reporters in a collection of S. pombe mutants, Cay1 and Tls1 were identified as additional regulators of this process. The role of Sde2, Cay1 and Tls1 was further confirmed by increasing BP-3'ss spacings in a canonical tho5 intron. We also examined BP-distant exons spliced independently of these factors and observed that RNA secondary structures possibly bridged the gap between the two signals. These proteins may guide the 3'ss towards the spliceosome's catalytic centre by folding the RNA between the BP and 3'ss. Orthologues of Sde2, Cay1 and Tls1, although missing in the intron-poor Saccharomyces cerevisiae, are present in intron-rich eukaryotes, including humans. This type of intron-specific pre-mRNA splicing appears to have evolved for regulated gene expression and alternative splicing of key heterochromatin factors.
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Affiliation(s)
- Anupa T Anil
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Karan Choudhary
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Rakesh Pandian
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Praver Gupta
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Poonam Thakran
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Arashdeep Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Monika Sharma
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Shravan Kumar Mishra
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
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5
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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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6
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Covelo-Molares H, Obrdlik A, Poštulková I, Dohnálková M, Gregorová P, Ganji R, Potěšil D, Gawriyski L, Varjosalo M, Vaňáčová Š. The comprehensive interactomes of human adenosine RNA methyltransferases and demethylases reveal distinct functional and regulatory features. Nucleic Acids Res 2021; 49:10895-10910. [PMID: 34634806 PMCID: PMC8565353 DOI: 10.1093/nar/gkab900] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 09/18/2021] [Accepted: 09/22/2021] [Indexed: 12/26/2022] Open
Abstract
N6-methyladenosine (m6A) and N6,2′-O-dimethyladenosine (m6Am) are two abundant modifications found in mRNAs and ncRNAs that can regulate multiple aspects of RNA biology. They function mainly by regulating interactions with specific RNA-binding proteins. Both modifications are linked to development, disease and stress response. To date, three methyltransferases and two demethylases have been identified that modify adenosines in mammalian mRNAs. Here, we present a comprehensive analysis of the interactomes of these enzymes. PCIF1 protein network comprises mostly factors involved in nascent RNA synthesis by RNA polymerase II, whereas ALKBH5 is closely linked with most aspects of pre-mRNA processing and mRNA export to the cytoplasm. METTL16 resides in subcellular compartments co-inhabited by several other RNA modifiers and processing factors. FTO interactome positions this demethylase at a crossroad between RNA transcription, RNA processing and DNA replication and repair. Altogether, these enzymes share limited spatial interactomes, pointing to specific molecular mechanisms of their regulation.
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Affiliation(s)
- Helena Covelo-Molares
- Central European Institute of Technology (CEITEC), Masaryk University, Brno 62500, Czech Republic
| | - Ales Obrdlik
- Central European Institute of Technology (CEITEC), Masaryk University, Brno 62500, Czech Republic
| | - Ivana Poštulková
- Central European Institute of Technology (CEITEC), Masaryk University, Brno 62500, Czech Republic
| | - Michaela Dohnálková
- Central European Institute of Technology (CEITEC), Masaryk University, Brno 62500, Czech Republic
| | - Pavlína Gregorová
- Central European Institute of Technology (CEITEC), Masaryk University, Brno 62500, Czech Republic
| | - Ranjani Ganji
- Central European Institute of Technology (CEITEC), Masaryk University, Brno 62500, Czech Republic
| | - David Potěšil
- Central European Institute of Technology (CEITEC), Masaryk University, Brno 62500, Czech Republic
| | - Lisa Gawriyski
- Institute of Biotechnology & HiLIFE - Helsinki Institute of Life Science, University of Helsinki, Helsinki 00014, Finland
| | - Markku Varjosalo
- Institute of Biotechnology & HiLIFE - Helsinki Institute of Life Science, University of Helsinki, Helsinki 00014, Finland
| | - Štěpánka Vaňáčová
- Central European Institute of Technology (CEITEC), Masaryk University, Brno 62500, Czech Republic
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7
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Floro J, Dai A, Metzger A, Mora-Martin A, Ganem N, Cifuentes D, Wu CS, Dalal J, Lyons S, Labadorf A, Flynn R. SDE2 is an essential gene required for ribosome biogenesis and the regulation of alternative splicing. Nucleic Acids Res 2021; 49:9424-9443. [PMID: 34365507 PMCID: PMC8450105 DOI: 10.1093/nar/gkab647] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 07/08/2021] [Accepted: 07/21/2021] [Indexed: 11/22/2022] Open
Abstract
RNA provides the framework for the assembly of some of the most intricate macromolecular complexes within the cell, including the spliceosome and the mature ribosome. The assembly of these complexes relies on the coordinated association of RNA with hundreds of trans-acting protein factors. While some of these trans-acting factors are RNA-binding proteins (RBPs), others are adaptor proteins, and others still, function as both. Defects in the assembly of these complexes results in a number of human pathologies including neurodegeneration and cancer. Here, we demonstrate that Silencing Defective 2 (SDE2) is both an RNA binding protein and also a trans-acting adaptor protein that functions to regulate RNA splicing and ribosome biogenesis. SDE2 depletion leads to widespread changes in alternative splicing, defects in ribosome biogenesis and ultimately complete loss of cell viability. Our data highlight SDE2 as a previously uncharacterized essential gene required for the assembly and maturation of the complexes that carry out two of the most fundamental processes in mammalian cells.
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Affiliation(s)
- Jess Floro
- Departments of Pharmacology and Experimental Therapeutics, and Medicine, Cancer Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Anqi Dai
- Departments of Pharmacology and Experimental Therapeutics, and Medicine, Cancer Center, Boston University School of Medicine, Boston, MA 02118, USA
- Bioinformatics Program, Boston University, Boston, MA 02118 USA
| | - Abigail Metzger
- Departments of Pharmacology and Experimental Therapeutics, and Medicine, Cancer Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Alexandra Mora-Martin
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Neil J Ganem
- Departments of Pharmacology and Experimental Therapeutics, and Medicine, Cancer Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Daniel Cifuentes
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Ching-Shyi Wu
- Department and Graduate Institute of Pharmacology, National Taiwan University College of Medicine, Taipei, 10051, Taiwan
| | - Jasbir Dalal
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Shawn M Lyons
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Adam Labadorf
- Bioinformatics Program, Boston University, Boston, MA 02118 USA
- Department of Neurology, Boston University School of Medicine, Boston, MA 02118 USA
| | - Rachel L Flynn
- Departments of Pharmacology and Experimental Therapeutics, and Medicine, Cancer Center, Boston University School of Medicine, Boston, MA 02118, USA
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8
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Mohanta A, Chakrabarti K. Dbr1 functions in mRNA processing, intron turnover and human diseases. Biochimie 2020; 180:134-142. [PMID: 33038423 DOI: 10.1016/j.biochi.2020.10.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/01/2020] [Accepted: 10/05/2020] [Indexed: 12/29/2022]
Abstract
Pre-mRNA processing and mRNA stability play direct roles in controlling protein abundance in a cell. Before the mRNA can be translated into a protein, the introns in the pre-mRNA transcripts need to be removed by splicing, such that exons can be ligated together and can code for a protein. In this process, the function of the RNA lariat debranching enzyme or Dbr1 provides a rate-limiting step in the intron turnover process and possibly regulating the production of translation competent mRNAs. Surprising new roles of Dbr1 are emerging in cellular metabolism which extends beyond intron turnover processes, ranging from splicing regulation to translational control. In this review, we highlight the importance of the Dbr1 enzyme, its structure and how anomalies in its function could relate to various human diseases.
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Affiliation(s)
- Arundhati Mohanta
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA
| | - Kausik Chakrabarti
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA.
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9
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Wang J, Chen S, Jiang N, Li N, Wang X, Li Z, Li X, Liu H, Li L, Yang Y, Ni T, Yu C, Ma J, Zheng B, Ren G. Spliceosome disassembly factors ILP1 and NTR1 promote miRNA biogenesis in Arabidopsis thaliana. Nucleic Acids Res 2019; 47:7886-7900. [PMID: 31216029 PMCID: PMC6736097 DOI: 10.1093/nar/gkz526] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 05/13/2019] [Accepted: 06/03/2019] [Indexed: 12/23/2022] Open
Abstract
The intron-lariat spliceosome (ILS) complex is highly conserved among eukaryotes, and its disassembly marks the end of a canonical splicing cycle. In this study, we show that two conserved disassembly factors of the ILS complex, Increased Level of Polyploidy1-1D (ILP1) and NTC-Related protein 1 (NTR1), positively regulate microRNA (miRNA) biogenesis by facilitating transcriptional elongation of MIRNA (MIR) genes in Arabidopsis thaliana. ILP1 and NTR1 formed a stable complex and co-regulated alternative splicing of more than a hundred genes across the Arabidopsis genome, including some primary transcripts of miRNAs (pri-miRNAs). Intriguingly, pri-miRNAs, regardless of having introns or not, were globally down-regulated when the ILP1 or NTR1 function was compromised. ILP1 and NTR1 interacted with core miRNA processing proteins Dicer-like 1 and Serrate, and were required for proper RNA polymerase II occupancy at elongated regions of MIR chromatin, without affecting either MIR promoter activity or pri-miRNA decay. Our results provide further insights into the regulatory role of spliceosomal machineries in the biogenesis of miRNAs.
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Affiliation(s)
- Junli Wang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Susu Chen
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Ning Jiang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Ning Li
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Xiaoyan Wang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Zhongpeng Li
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Xu Li
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences, Shanghai 200032, P.R. China
| | - Hongtao Liu
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences, Shanghai 200032, P.R. China
| | - Lin Li
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Yu Yang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Ting Ni
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Chaoyi Yu
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Jinbiao Ma
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Binglian Zheng
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Guodong Ren
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Huashan Hospital and School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
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10
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Toroney R, Nielsen KH, Staley JP. Termination of pre-mRNA splicing requires that the ATPase and RNA unwindase Prp43p acts on the catalytic snRNA U6. Genes Dev 2019; 33:1555-1574. [PMID: 31558568 PMCID: PMC6824469 DOI: 10.1101/gad.328294.119] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 09/03/2019] [Indexed: 11/25/2022]
Abstract
In this study, Toroney et al. set out to identify the mechanism of Prp43p action in splicing. The authors use biochemical approaches to demonstrate that the 3' end of U6 acts as the key substrate by which Prp43p promotes disassembly and intron release, thereby terminating splicing. The termination of pre-mRNA splicing functions to discard suboptimal substrates, thereby enhancing fidelity, and to release excised introns in a manner coupled to spliceosome disassembly, thereby allowing recycling. The mechanism of termination, including the RNA target of the DEAH-box ATPase Prp43p, remains ambiguous. We discovered a critical role for nucleotides at the 3′ end of the catalytic U6 small nuclear RNA in splicing termination. Although conserved sequence at the 3′ end is not required, 2′ hydroxyls are, paralleling requirements for Prp43p biochemical activities. Although the 3′ end of U6 is not required for recruiting Prp43p to the spliceosome, the 3′ end cross-links directly to Prp43p in an RNA-dependent manner. Our data indicate a mechanism of splicing termination in which Prp43p translocates along U6 from the 3′ end to disassemble the spliceosome and thereby release suboptimal substrates or excised introns. This mechanism reveals that the spliceosome becomes primed for termination at the same stage it becomes activated for catalysis, implying a requirement for stringent control of spliceosome activity within the cell.
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Affiliation(s)
- Rebecca Toroney
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637, USA
| | - Klaus H Nielsen
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637, USA
| | - Jonathan P Staley
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637, USA
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11
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Yan C, Wan R, Shi Y. Molecular Mechanisms of pre-mRNA Splicing through Structural Biology of the Spliceosome. Cold Spring Harb Perspect Biol 2019; 11:11/1/a032409. [PMID: 30602541 DOI: 10.1101/cshperspect.a032409] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Precursor messenger RNA (pre-mRNA) splicing is executed by the spliceosome. In the past 3 years, cryoelectron microscopy (cryo-EM) structures have been elucidated for a majority of the yeast spliceosomal complexes and for a few human spliceosomes. During the splicing reaction, the dynamic spliceosome has an immobile core of about 20 protein and RNA components, which are organized around a conserved splicing active site. The divalent metal ions, coordinated by U6 small nuclear RNA (snRNA), catalyze the branching reaction and exon ligation. The spliceosome also contains a mobile but compositionally stable group of about 13 proteins and a portion of U2 snRNA, which facilitate substrate delivery into the splicing active site. The spliceosomal transitions are driven by the RNA-dependent ATPase/helicases, resulting in the recruitment and dissociation of specific splicing factors that enable the reaction. In summary, the spliceosome is a protein-directed metalloribozyme.
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Affiliation(s)
- Chuangye Yan
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ruixue Wan
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.,Institute of Biology, Westlake Institute for Advanced Study, Westlake University, Hangzhou 310064, Zhejiang Province, China
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12
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Emerging Roles of Ubiquitin-like Proteins in Pre-mRNA Splicing. Trends Biochem Sci 2018; 43:896-907. [PMID: 30269981 DOI: 10.1016/j.tibs.2018.09.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/31/2018] [Accepted: 09/06/2018] [Indexed: 12/12/2022]
Abstract
Ubiquitin-like proteins (UBLs) belong to the protein family whose members share a globular beta-grasp fold structure. The archetypal member, ubiquitin, is known for its function in proteasome-mediated protein degradation. UBLs have been shown to play several crucial roles besides protein turnover, including DNA damage response, cell cycle control, cellular signaling, protein trafficking, and innate immunity activation. In the past few years, accumulating evidence illustrates that four UBLs, namely, ubiquitin, SUMO, Hub1, and Sde2, are involved in eukaryotic pre-mRNA splicing. They modify the spliceosomes and promote splicing by adding new surfaces for intermolecular interactions, thereby refining the outcome of gene expression. In this review article, we highlight recent discoveries with an emphasis on the emerging roles of UBLs in splicing regulation.
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13
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Herzel L, Straube K, Neugebauer KM. Long-read sequencing of nascent RNA reveals coupling among RNA processing events. Genome Res 2018; 28:1008-1019. [PMID: 29903723 PMCID: PMC6028129 DOI: 10.1101/gr.232025.117] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 05/24/2018] [Indexed: 12/13/2022]
Abstract
Pre-mRNA splicing is accomplished by the spliceosome, a megadalton complex that assembles de novo on each intron. Because spliceosome assembly and catalysis occur cotranscriptionally, we hypothesized that introns are removed in the order of their transcription in genomes dominated by constitutive splicing. Remarkably little is known about splicing order and the regulatory potential of nascent transcript remodeling by splicing, due to the limitations of existing methods that focus on analysis of mature splicing products (mRNAs) rather than substrates and intermediates. Here, we overcome this obstacle through long-read RNA sequencing of nascent, multi-intron transcripts in the fission yeast Schizosaccharomyces pombe. Most multi-intron transcripts were fully spliced, consistent with rapid cotranscriptional splicing. However, an unexpectedly high proportion of transcripts were either fully spliced or fully unspliced, suggesting that splicing of any given intron is dependent on the splicing status of other introns in the transcript. Supporting this, mild inhibition of splicing by a temperature-sensitive mutation in prp2, the homolog of vertebrate U2AF65, increased the frequency of fully unspliced transcripts. Importantly, fully unspliced transcripts displayed transcriptional read-through at the polyA site and were degraded cotranscriptionally by the nuclear exosome. Finally, we show that cellular mRNA levels were reduced in genes with a high number of unspliced nascent transcripts during caffeine treatment, showing regulatory significance of cotranscriptional splicing. Therefore, overall splicing of individual nascent transcripts, 3′ end formation, and mRNA half-life depend on the splicing status of neighboring introns, suggesting crosstalk among spliceosomes and the polyA cleavage machinery during transcription elongation.
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Affiliation(s)
- Lydia Herzel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Korinna Straube
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
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14
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Chen W, Moore J, Ozadam H, Shulha HP, Rhind N, Weng Z, Moore MJ. Transcriptome-wide Interrogation of the Functional Intronome by Spliceosome Profiling. Cell 2018; 173:1031-1044.e13. [PMID: 29727662 PMCID: PMC6090549 DOI: 10.1016/j.cell.2018.03.062] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 02/09/2018] [Accepted: 03/23/2018] [Indexed: 12/31/2022]
Abstract
Full understanding of eukaryotic transcriptomes and how they respond to different conditions requires deep knowledge of all sites of intron excision. Although RNA sequencing (RNA-seq) provides much of this information, the low abundance of many spliced transcripts (often due to their rapid cytoplasmic decay) limits the ability of RNA-seq alone to reveal the full repertoire of spliced species. Here, we present "spliceosome profiling," a strategy based on deep sequencing of RNAs co-purifying with late-stage spliceosomes. Spliceosome profiling allows for unambiguous mapping of intron ends to single-nucleotide resolution and branchpoint identification at unprecedented depths. Our data reveal hundreds of new introns in S. pombe and numerous others that were previously misannotated. By providing a means to directly interrogate sites of spliceosome assembly and catalysis genome-wide, spliceosome profiling promises to transform our understanding of RNA processing in the nucleus, much as ribosome profiling has transformed our understanding mRNA translation in the cytoplasm.
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Affiliation(s)
- Weijun Chen
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jill Moore
- Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Hakan Ozadam
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Hennady P Shulha
- Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Nicholas Rhind
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Zhiping Weng
- Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Melissa J Moore
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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15
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Wilkinson ME, Lin PC, Plaschka C, Nagai K. Cryo-EM Studies of Pre-mRNA Splicing: From Sample Preparation to Model Visualization. Annu Rev Biophys 2018; 47:175-199. [PMID: 29494253 DOI: 10.1146/annurev-biophys-070317-033410] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The removal of noncoding introns from pre-messenger RNA (pre-mRNA) is an essential step in eukaryotic gene expression and is catalyzed by a dynamic multi-megadalton ribonucleoprotein complex called the spliceosome. The spliceosome assembles on pre-mRNA substrates by the stepwise addition of small nuclear ribonucleoprotein particles and numerous protein factors. Extensive remodeling is required to form the RNA-based active site and to mediate the pre-mRNA branching and ligation reactions. In the past two years, cryo-electron microscopy (cryo-EM) structures of spliceosomes captured in different assembly and catalytic states have greatly advanced our understanding of its mechanism. This was made possible by long-standing efforts in the purification of spliceosome intermediates as well as recent developments in cryo-EM imaging and computational methodology. The resulting high-resolution densities allow for de novo model building in core regions of the complexes. In peripheral and less ordered regions, the combination of cross-linking, bioinformatics, biochemical, and genetic data is essential for accurate modeling. Here, we summarize these achievements and highlight the critical steps in obtaining near-atomic resolution structures of the spliceosome.
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Affiliation(s)
- Max E Wilkinson
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom; , , ,
| | - Pei-Chun Lin
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom; , , ,
| | - Clemens Plaschka
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom; , , ,
| | - Kiyoshi Nagai
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom; , , ,
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16
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Mechanistic insights into precursor messenger RNA splicing by the spliceosome. Nat Rev Mol Cell Biol 2017; 18:655-670. [DOI: 10.1038/nrm.2017.86] [Citation(s) in RCA: 234] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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17
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Thakran P, Pandit PA, Datta S, Kolathur KK, Pleiss JA, Mishra SK. Sde2 is an intron-specific pre-mRNA splicing regulator activated by ubiquitin-like processing. EMBO J 2017; 37:89-101. [PMID: 28947618 DOI: 10.15252/embj.201796751] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 08/11/2017] [Accepted: 08/16/2017] [Indexed: 12/31/2022] Open
Abstract
The expression of intron-containing genes in eukaryotes requires generation of protein-coding messenger RNAs (mRNAs) via RNA splicing, whereby the spliceosome removes non-coding introns from pre-mRNAs and joins exons. Spliceosomes must ensure accurate removal of highly diverse introns. We show that Sde2 is a ubiquitin-fold-containing splicing regulator that supports splicing of selected pre-mRNAs in an intron-specific manner in Schizosaccharomyces pombe Both fission yeast and human Sde2 are translated as inactive precursor proteins harbouring the ubiquitin-fold domain linked through an invariant GGKGG motif to a C-terminal domain (referred to as Sde2-C). Precursor processing after the first di-glycine motif by the ubiquitin-specific proteases Ubp5 and Ubp15 generates a short-lived activated Sde2-C fragment with an N-terminal lysine residue, which subsequently gets incorporated into spliceosomes. Absence of Sde2 or defects in Sde2 activation both result in inefficient excision of selected introns from a subset of pre-mRNAs. Sde2 facilitates spliceosomal association of Cactin/Cay1, with a functional link between Sde2 and Cactin further supported by genetic interactions and pre-mRNA splicing assays. These findings suggest that ubiquitin-like processing of Sde2 into a short-lived activated form may function as a checkpoint to ensure proper splicing of certain pre-mRNAs in fission yeast.
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Affiliation(s)
- Poonam Thakran
- Max Planck - DST Partner Group, Department of Biological Sciences, Centre for Protein Science Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India
| | - Prashant Arun Pandit
- Max Planck - DST Partner Group, Department of Biological Sciences, Centre for Protein Science Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India
| | - Sumanjit Datta
- Max Planck - DST Partner Group, Department of Biological Sciences, Centre for Protein Science Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India
| | - Kiran Kumar Kolathur
- Max Planck - DST Partner Group, Department of Biological Sciences, Centre for Protein Science Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India
| | - Jeffrey A Pleiss
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Shravan Kumar Mishra
- Max Planck - DST Partner Group, Department of Biological Sciences, Centre for Protein Science Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India
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18
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Scheres SH, Nagai K. CryoEM structures of spliceosomal complexes reveal the molecular mechanism of pre-mRNA splicing. Curr Opin Struct Biol 2017; 46:130-139. [PMID: 28888105 DOI: 10.1016/j.sbi.2017.08.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 07/26/2017] [Accepted: 08/07/2017] [Indexed: 01/09/2023]
Abstract
The spliceosome is an intricate molecular machine which catalyses the removal of introns from eukaryotic mRNA precursors by two trans-esterification reactions (branching and exon ligation) to produce mature mRNA with uninterrupted protein coding sequences. The structures of the spliceosome in several key states determined by electron cryo-microscopy have greatly advanced our understanding of its molecular mechanism. The catalytic RNA core is formed during the activation of the fully assembled B to Bact complex and remains largely unchanged throughout the splicing cycle. RNA helicases and step specific factors regulate docking and undocking of the substrates (branch site and 3' splice site) to the single RNA-based active site to catalyse the two trans-esterification reactions.
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Affiliation(s)
- Sjors Hw Scheres
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom.
| | - Kiyoshi Nagai
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom.
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19
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Abstract
Here we focus on the biogenesis and function of messenger RNA (mRNA) in fission yeast cells. Following a general introduction that also briefly touches on other classes of RNA, we provide an overview of methods used to analyze mRNAs throughout their life cycles.
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Affiliation(s)
- Jo Ann Wise
- Center for RNA Molecular Biology and Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106-4906
| | - Olaf Nielsen
- Department of Biology, Functional Genomics Division, University of Copenhagen, DK-2200 Copenhagen, Denmark
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20
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Cryo-EM structure of the spliceosome immediately after branching. Nature 2016; 537:197-201. [PMID: 27459055 PMCID: PMC5156311 DOI: 10.1038/nature19316] [Citation(s) in RCA: 177] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 07/19/2016] [Indexed: 12/11/2022]
Abstract
Precursor mRNA (pre-mRNA) splicing proceeds by two consecutive transesterification reactions via a lariat-intron intermediate. Here we present the 3.8 Å cryo-electron microscopy structure of the spliceosome immediately after lariat formation. The 5'-splice site is cleaved but remains close to the catalytic Mg2+ site in the U2/U6 small nuclear RNA (snRNA) triplex, and the 5'-phosphate of the intron nucleotide G(+1) is linked to the branch adenosine 2'OH. The 5'-exon is held between the Prp8 amino-terminal and linker domains, and base-pairs with U5 snRNA loop 1. Non-Watson-Crick interactions between the branch helix and 5'-splice site dock the branch adenosine into the active site, while intron nucleotides +3 to +6 base-pair with the U6 snRNA ACAGAGA sequence. Isy1 and the step-one factors Yju2 and Cwc25 stabilize docking of the branch helix. The intron downstream of the branch site emerges between the Prp8 reverse transcriptase and linker domains and extends towards the Prp16 helicase, suggesting a plausible mechanism of remodelling before exon ligation.
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21
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Yan C, Wan R, Bai R, Huang G, Shi Y. Structure of a yeast activated spliceosome at 3.5 Å resolution. Science 2016; 353:904-11. [PMID: 27445306 DOI: 10.1126/science.aag0291] [Citation(s) in RCA: 200] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/13/2016] [Indexed: 12/18/2022]
Abstract
Pre-messenger RNA (pre-mRNA) splicing is carried out by the spliceosome, which undergoes an intricate assembly and activation process. Here, we report an atomic structure of an activated spliceosome (known as the B(act) complex) from Saccharomyces cerevisiae, determined by cryo-electron microscopy at an average resolution of 3.52 angstroms. The final refined model contains U2 and U5 small nuclear ribonucleoprotein particles (snRNPs), U6 small nuclear RNA (snRNA), nineteen complex (NTC), NTC-related (NTR) protein, and a 71-nucleotide pre-mRNA molecule, which amount to 13,505 amino acids from 38 proteins and a combined molecular mass of about 1.6 megadaltons. The 5' exon is anchored by loop I of U5 snRNA, whereas the 5' splice site (5'SS) and the branch-point sequence (BPS) of the intron are specifically recognized by U6 and U2 snRNA, respectively. Except for coordination of the catalytic metal ions, the RNA elements at the catalytic cavity of Prp8 are mostly primed for catalysis. The catalytic latency is maintained by the SF3b complex, which encircles the BPS, and the splicing factors Cwc24 and Prp11, which shield the 5' exon-5'SS junction. This structure, together with those determined earlier, outlines a molecular framework for the pre-mRNA splicing reaction.
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Affiliation(s)
- Chuangye Yan
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ruixue Wan
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Rui Bai
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Gaoxingyu Huang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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22
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Wan R, Yan C, Bai R, Huang G, Shi Y. Structure of a yeast catalytic step I spliceosome at 3.4 Å resolution. Science 2016; 353:895-904. [PMID: 27445308 DOI: 10.1126/science.aag2235] [Citation(s) in RCA: 162] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 07/14/2016] [Indexed: 12/30/2022]
Abstract
Each cycle of pre-messenger RNA splicing, carried out by the spliceosome, comprises two sequential transesterification reactions, which result in the removal of an intron and the joining of two exons. Here we report an atomic structure of a catalytic step I spliceosome (known as the C complex) from Saccharomyces cerevisiae, as determined by cryo-electron microscopy at an average resolution of 3.4 angstroms. In the structure, the 2'-OH of the invariant adenine nucleotide in the branch point sequence (BPS) is covalently joined to the phosphate at the 5' end of the 5' splice site (5'SS), forming an intron lariat. The freed 5' exon remains anchored to loop I of U5 small nuclear RNA (snRNA), and the 5'SS and BPS of the intron form duplexes with conserved U6 and U2 snRNA sequences, respectively. Specific placement of these RNA elements at the catalytic cavity of Prp8 is stabilized by 15 protein components, including Snu114 and the splicing factors Cwc21, Cwc22, Cwc25, and Yju2. These features, representing the conformation of the spliceosome after the first-step reaction, predict structural changes that are needed for the execution of the second-step transesterification reaction.
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Affiliation(s)
- Ruixue Wan
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Chuangye Yan
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Rui Bai
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Gaoxingyu Huang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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23
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Interconnections Between RNA-Processing Pathways Revealed by a Sequencing-Based Genetic Screen for Pre-mRNA Splicing Mutants in Fission Yeast. G3-GENES GENOMES GENETICS 2016; 6:1513-23. [PMID: 27172183 PMCID: PMC4889648 DOI: 10.1534/g3.116.027508] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Pre-mRNA splicing is an essential component of eukaryotic gene expression and is highly conserved from unicellular yeasts to humans. Here, we present the development and implementation of a sequencing-based reverse genetic screen designed to identify nonessential genes that impact pre-mRNA splicing in the fission yeast Schizosaccharomyces pombe, an organism that shares many of the complex features of splicing in higher eukaryotes. Using a custom-designed barcoding scheme, we simultaneously queried ∼3000 mutant strains for their impact on the splicing efficiency of two endogenous pre-mRNAs. A total of 61 nonessential genes were identified whose deletions resulted in defects in pre-mRNA splicing; enriched among these were factors encoding known or predicted components of the spliceosome. Included among the candidates identified here are genes with well-characterized roles in other RNA-processing pathways, including heterochromatic silencing and 3ʹ end processing. Splicing-sensitive microarrays confirm broad splicing defects for many of these factors, revealing novel functional connections between these pathways.
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24
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Nguyen THD, Galej WP, Bai XC, Oubridge C, Newman AJ, Scheres SHW, Nagai K. Cryo-EM structure of the yeast U4/U6.U5 tri-snRNP at 3.7 Å resolution. Nature 2016; 530:298-302. [PMID: 26829225 PMCID: PMC4762201 DOI: 10.1038/nature16940] [Citation(s) in RCA: 162] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 12/18/2015] [Indexed: 12/12/2022]
Abstract
U4/U6.U5 tri-snRNP represents a substantial part of the spliceosome before activation. A cryoEM structure of Saccharomyces cerevisiae U4/U6.U5 tri-snRNP at 3.7Å resolution led to an essentially complete atomic model comprising 30 proteins plus U4/U6 and U5 snRNAs. The structure reveals striking interweaving interactions of the protein and RNA components including extended polypeptides penetrating into subunit interfaces. The invariant ACAGAGA sequence of U6 snRNA, which base-pairs with the 5′-splice site during catalytic activation, forms a hairpin stabilised by Dib1 and Prp8 while the adjacent nucleotides interact with the exon binding loop 1 of U5 snRNA. Snu114 harbours GTP but its putative catalytic histidine is held away from the γ-phosphate by hydrogen bonding to a tyrosine in Prp8’s N-terminal domain. Mutation of this histidine to alanine has no detectable effect on yeast growth. The structure provides important new insights into the spliceosome activation process leading to the formation of the catalytic centre.
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Affiliation(s)
| | - Wojciech P Galej
- MRC Laboratory of Molecular Biology Francis Crick Avenue Cambridge CB2 0QH UK
| | - Xiao-Chen Bai
- MRC Laboratory of Molecular Biology Francis Crick Avenue Cambridge CB2 0QH UK
| | - Chris Oubridge
- MRC Laboratory of Molecular Biology Francis Crick Avenue Cambridge CB2 0QH UK
| | - Andrew J Newman
- MRC Laboratory of Molecular Biology Francis Crick Avenue Cambridge CB2 0QH UK
| | - Sjors H W Scheres
- MRC Laboratory of Molecular Biology Francis Crick Avenue Cambridge CB2 0QH UK
| | - Kiyoshi Nagai
- MRC Laboratory of Molecular Biology Francis Crick Avenue Cambridge CB2 0QH UK
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25
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Qin D, Huang L, Wlodaver A, Andrade J, Staley JP. Sequencing of lariat termini in S. cerevisiae reveals 5' splice sites, branch points, and novel splicing events. RNA (NEW YORK, N.Y.) 2016; 22:237-53. [PMID: 26647463 PMCID: PMC4712674 DOI: 10.1261/rna.052829.115] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 11/04/2015] [Indexed: 05/23/2023]
Abstract
Pre-mRNA splicing is a central step in the shaping of the eukaryotic transcriptome and in the regulation of gene expression. Yet, due to a focus on fully processed mRNA, common approaches for defining pre-mRNA splicing genome-wide are suboptimal-especially with respect to defining the branch point sequence, a key cis-element that initiates the chemistry of splicing. Here, we report a complementary intron-centered approach designed to more efficiently, simply, and directly define splicing events genome-wide. Specifically, we developed a method distinguished by deep sequencing of lariat intron termini (LIT-seq). In a test of LIT-seq using the budding yeast Saccharomyces cerevisiae, we not only successfully captured the majority of annotated, expressed splicing events but also uncovered 45 novel splicing events, establishing the sensitivity of LIT-seq. Moreover, our libraries were highly enriched with reads that reported on splice sites; by a simple and direct inspection of sequencing reads, we empirically defined both 5' splice sites and branch sites, as well as their consensus sequences, with nucleotide resolution. Additionally, our study revealed that the 3' termini of lariat introns are subject to nontemplated addition of adenosines, characteristic of signals sensed by 3' to 5' RNA turnover machinery. Collectively, this work defines a novel, genome-wide approach for analyzing splicing with unprecedented depth, specificity, and resolution.
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Affiliation(s)
- Daoming Qin
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637, USA
| | - Lei Huang
- Center for Research Informatics, University of Chicago, Chicago, Illinois 60637, USA
| | - Alissa Wlodaver
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637, USA
| | - Jorge Andrade
- Center for Research Informatics, University of Chicago, Chicago, Illinois 60637, USA
| | - Jonathan P Staley
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637, USA
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26
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CryoEM structures of two spliceosomal complexes: starter and dessert at the spliceosome feast. Curr Opin Struct Biol 2016; 36:48-57. [PMID: 26803803 PMCID: PMC4830896 DOI: 10.1016/j.sbi.2015.12.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 12/21/2015] [Indexed: 12/31/2022]
Abstract
Recent advances in cryoEM are revolutionizing our understanding of how molecular machines function. The structure of Saccharomyces cerevisiae U4/U6.U5 tri-snRNP has been revealed. The structure of Schizosaccharomyces pombe U2.U6.U5 spliceosomal complex has been revealed. These structures greatly advanced our understanding of the mechanism of pre-mRNA splicing.
The spliceosome is formed on pre-mRNA substrates from five small nuclear ribonucleoprotein particles (U1, U2, U4/U6 and U5 snRNPs), and numerous non-snRNP factors. Saccharomyces cerevisiae U4/U6.U5 tri-snRNP comprises U5 snRNA, U4/U6 snRNA duplex and approximately 30 proteins and represents a substantial part of the spliceosome before activation. Schizosaccharomyces pombe U2.U6.U5 spliceosomal complex is a post-catalytic intron lariat spliceosome containing U2 and U5 snRNPs, NTC (nineteen complex), NTC-related proteins (NTR), U6 snRNA, and an RNA intron lariat. Two recent papers describe near-complete atomic structures of these complexes based on cryoEM single-particle analysis. The U4/U6.U5 tri-snRNP structure provides crucial insight into the activation mechanism of the spliceosome. The U2.U6.U5 complex reveals the striking architecture of NTC and NTR and important features of the group II intron-like catalytic RNA core remaining after spliced mRNA is released. These two structures greatly advance our understanding of the mechanism of pre-mRNA splicing.
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Wan R, Yan C, Bai R, Wang L, Huang M, Wong CCL, Shi Y. The 3.8 Å structure of the U4/U6.U5 tri-snRNP: Insights into spliceosome assembly and catalysis. Science 2016; 351:466-75. [PMID: 26743623 DOI: 10.1126/science.aad6466] [Citation(s) in RCA: 131] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/24/2015] [Indexed: 01/08/2023]
Abstract
Splicing of precursor messenger RNA is accomplished by a dynamic megacomplex known as the spliceosome. Assembly of a functional spliceosome requires a preassembled U4/U6.U5 tri-snRNP complex, which comprises the U5 small nuclear ribonucleoprotein (snRNP), the U4 and U6 small nuclear RNA (snRNA) duplex, and a number of protein factors. Here we report the three-dimensional structure of a Saccharomyces cerevisiae U4/U6.U5 tri-snRNP at an overall resolution of 3.8 angstroms by single-particle electron cryomicroscopy. The local resolution for the core regions of the tri-snRNP reaches 3.0 to 3.5 angstroms, allowing construction of a refined atomic model. Our structure contains U5 snRNA, the extensively base-paired U4/U6 snRNA, and 30 proteins including Prp8 and Snu114, which amount to 8495 amino acids and 263 nucleotides with a combined molecular mass of ~1 megadalton. The catalytic nucleotide U80 from U6 snRNA exists in an inactive conformation, stabilized by its base-pairing interactions with U4 snRNA and protected by Prp3. Pre-messenger RNA is bound in the tri-snRNP through base-pairing interactions with U6 snRNA and loop I of U5 snRNA. This structure, together with that of the spliceosome, reveals the molecular choreography of the snRNAs in the activation process of the spliceosomal ribozyme.
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Affiliation(s)
- Ruixue Wan
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Chuangye Yan
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Rui Bai
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lin Wang
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Min Huang
- National Center for Protein Science Shanghai, Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Catherine C L Wong
- National Center for Protein Science Shanghai, Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yigong Shi
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
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Aronica L, Kasparek T, Ruchman D, Marquez Y, Cipak L, Cipakova I, Anrather D, Mikolaskova B, Radtke M, Sarkar S, Pai CC, Blaikley E, Walker C, Shen KF, Schroeder R, Barta A, Forsburg SL, Humphrey TC. The spliceosome-associated protein Nrl1 suppresses homologous recombination-dependent R-loop formation in fission yeast. Nucleic Acids Res 2015; 44:1703-17. [PMID: 26682798 PMCID: PMC4770224 DOI: 10.1093/nar/gkv1473] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 12/03/2015] [Indexed: 01/07/2023] Open
Abstract
The formation of RNA–DNA hybrids, referred to as R-loops, can promote genome instability and cancer development. Yet the mechanisms by which R-loops compromise genome instability are poorly understood. Here, we establish roles for the evolutionarily conserved Nrl1 protein in pre-mRNA splicing regulation, R-loop suppression and in maintaining genome stability. nrl1Δ mutants exhibit endogenous DNA damage, are sensitive to exogenous DNA damage, and have defects in homologous recombination (HR) repair. Concomitantly, nrl1Δ cells display significant changes in gene expression, similar to those induced by DNA damage in wild-type cells. Further, we find that nrl1Δ cells accumulate high levels of R-loops, which co-localize with HR repair factors and require Rad51 and Rad52 for their formation. Together, our findings support a model in which R-loop accumulation and subsequent DNA damage sequesters HR factors, thereby compromising HR repair at endogenously or exogenously induced DNA damage sites, leading to genome instability.
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Affiliation(s)
- Lucia Aronica
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, Vienna A-1030, Austria Department of Oncology, Stanford University, Stanford 94305, USA
| | - Torben Kasparek
- CRUK/MRC Oxford Institute for Radiation Oncology, Oxford OX37DQ , UK
| | - David Ruchman
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, Vienna A-1030, Austria
| | - Yamile Marquez
- Department of Medical Biochemistry, Max F. Perutz Laboratories,Medical University of Vienna, Vienna A-1030, Austria
| | - Lubos Cipak
- Cancer Research Institute, Slovak Academy of Sciences, Bratislava 81438, Slovakia
| | - Ingrid Cipakova
- Cancer Research Institute, Slovak Academy of Sciences, Bratislava 81438, Slovakia
| | - Dorothea Anrather
- Max F. Perutz Laboratories, Mass Spectrometry Facility, Vienna A-1030, Austria
| | - Barbora Mikolaskova
- Cancer Research Institute, Slovak Academy of Sciences, Bratislava 81438, Slovakia
| | - Maximilian Radtke
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, Vienna A-1030, Austria
| | - Sovan Sarkar
- CRUK/MRC Oxford Institute for Radiation Oncology, Oxford OX37DQ , UK
| | - Chen-Chun Pai
- CRUK/MRC Oxford Institute for Radiation Oncology, Oxford OX37DQ , UK
| | | | - Carol Walker
- CRUK/MRC Oxford Institute for Radiation Oncology, Oxford OX37DQ , UK
| | - Kuo-Fang Shen
- University of Southern California, Los Angeles 90089-0911, USA
| | - Renee Schroeder
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, Vienna A-1030, Austria
| | - Andrea Barta
- Department of Medical Biochemistry, Max F. Perutz Laboratories,Medical University of Vienna, Vienna A-1030, Austria
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Yan C, Hang J, Wan R, Huang M, Wong CCL, Shi Y. Structure of a yeast spliceosome at 3.6-angstrom resolution. Science 2015; 349:1182-91. [DOI: 10.1126/science.aac7629] [Citation(s) in RCA: 278] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 08/10/2015] [Indexed: 12/20/2022]
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van Maldegem F, Maslen S, Johnson CM, Chandra A, Ganesh K, Skehel M, Rada C. CTNNBL1 facilitates the association of CWC15 with CDC5L and is required to maintain the abundance of the Prp19 spliceosomal complex. Nucleic Acids Res 2015; 43:7058-69. [PMID: 26130721 PMCID: PMC4538830 DOI: 10.1093/nar/gkv643] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 06/09/2015] [Indexed: 12/16/2022] Open
Abstract
In order to catalyse the splicing of messenger RNA, multiple proteins and RNA components associate and dissociate in a dynamic highly choreographed process. The Prp19 complex is a conserved essential part of the splicing machinery thought to facilitate the conformational changes the spliceosome undergoes during catalysis. Dynamic protein interactions often involve highly disordered regions that are difficult to study by structural methods. Using amine crosslinking and hydrogen-deuterium exchange coupled to mass spectrometry, we describe the architecture of the Prp19 sub-complex that contains CTNNBL1. Deficiency in CTNNBL1 leads to delayed initiation of cell division and embryonic lethality. Here we show that in vitro CTNNBL1 enhances the association of CWC15 and CDC5L, both core Prp19 complex proteins and identify an overlap in the region of CDC5L that binds either CTNNBL1 or CWC15 suggesting the two proteins might exchange places in the complex. Furthermore, in vivo, CTNNBL1 is required to maintain normal levels of the Prp19 complex and to facilitate the interaction of CWC15 with CDC5L. Our results identify a chaperone function for CTNNBL1 within the essential Prp19 complex, a function required to maintain the integrity of the complex and to support efficient splicing.
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Affiliation(s)
| | - Sarah Maslen
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | | | - Anita Chandra
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Karuna Ganesh
- Department of Medicine and Cancer Biology & Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Mark Skehel
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Cristina Rada
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
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Heyer EE, Ozadam H, Ricci EP, Cenik C, Moore MJ. An optimized kit-free method for making strand-specific deep sequencing libraries from RNA fragments. Nucleic Acids Res 2014; 43:e2. [PMID: 25505164 PMCID: PMC4288154 DOI: 10.1093/nar/gku1235] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Deep sequencing of strand-specific cDNA libraries is now a ubiquitous tool for identifying and quantifying RNAs in diverse sample types. The accuracy of conclusions drawn from these analyses depends on precise and quantitative conversion of the RNA sample into a DNA library suitable for sequencing. Here, we describe an optimized method of preparing strand-specific RNA deep sequencing libraries from small RNAs and variably sized RNA fragments obtained from ribonucleoprotein particle footprinting experiments or fragmentation of long RNAs. Our approach works across a wide range of input amounts (400 pg to 200 ng), is easy to follow and produces a library in 2–3 days at relatively low reagent cost, all while giving the user complete control over every step. Because all enzymatic reactions were optimized and driven to apparent completion, sequence diversity and species abundance in the input sample are well preserved.
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Affiliation(s)
- Erin E Heyer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Hakan Ozadam
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Emiliano P Ricci
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Can Cenik
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Melissa J Moore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
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Wang J, Tadeo X, Hou H, Andrews S, Moresco JJ, Yates JR, Nagy PL, Jia S. Tls1 regulates splicing of shelterin components to control telomeric heterochromatin assembly and telomere length. Nucleic Acids Res 2014; 42:11419-32. [PMID: 25245948 PMCID: PMC4191416 DOI: 10.1093/nar/gku842] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Heterochromatin preferentially forms at repetitive DNA elements through RNAi-mediated targeting of histone-modifying enzymes. It was proposed that splicing factors interact with the RNAi machinery or regulate the splicing of repeat transcripts to directly participate in heterochromatin assembly. Here, by screening the fission yeast deletion library, we comprehensively identified factors required for telomeric heterochromatin assembly, including a novel gene tls1+. Purification of Tls1 and mass spectrometry analysis of its interacting proteins show that Tls1 associates with the spliceosome subunit Brr2. RNA sequencing analysis shows that the splicing of a subset of mRNAs are affected in tls1Δ cells, including mRNAs of shelterin components rap1+ and poz1+. Importantly, replacing rap1+ and poz1+ with their cDNAs significantly alleviated heterochromatin defects of tls1Δ cells, suggesting that the missplicing of shelterin components is the cause of such defects, and that splicing factors regulate telomeric heterochromatin through the proper splicing of heterochromatin factors. In addition to its role in telomeric heterochromatin assembly, Tls1-mediated splicing of shelterin mRNAs also regulates telomere length. Given that its human homologue C9ORF78 also associates with the spliceosome and is overexpressed in multiple cancer cell lines, our results suggest that C9ORF78 overexpression might alter the proper splicing of genes during cancer progression.
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Affiliation(s)
- Jiyong Wang
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Xavier Tadeo
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Haitong Hou
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Stuart Andrews
- Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - James J Moresco
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
| | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Peter L Nagy
- Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Songtao Jia
- Department of Biological Sciences, Columbia University, New York, NY, USA
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Valdés J, Nozaki T, Sato E, Chiba Y, Nakada-Tsukui K, Villegas-Sepúlveda N, Winkler R, Azuara-Liceaga E, Mendoza-Figueroa MS, Watanabe N, Santos HJ, Saito-Nakano Y, Galindo-Rosales JM. Proteomic analysis of Entamoeba histolytica in vivo assembled pre-mRNA splicing complexes. J Proteomics 2014; 111:30-45. [PMID: 25109466 DOI: 10.1016/j.jprot.2014.07.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 06/27/2014] [Accepted: 07/23/2014] [Indexed: 10/24/2022]
Abstract
UNLABELLED The genome of the human intestinal parasite Entamoeba histolytica contains nearly 3000 introns and bioinformatic predictions indicate that major and minor spliceosomes occur in Entamoeba. However, except for the U2-, U4-, U5- and U6 snRNAs, no other splicing factor has been cloned and characterized. Here, we HA-tagged cloned the snRNP component U1A and assessed its expression and nuclear localization. Because the snRNP-free U1A form interacts with polyadenylate-binding protein, HA-U1A immunoprecipitates could identify early and late splicing complexes. Avoiding Entamoeba's endonucleases and ensuring the precipitation of RNA-binding proteins, parasite cultures were UV cross-linked prior to nuclear fraction immunoprecipitations with HA antibodies, and precipitates were subjected to tandem mass spectrometry (MS/MS) analyses. To discriminate their nuclear roles (chromatin-, co-transcriptional-, splicing-related), MS/MS analyses were carried out with proteins eluted with MS2-GST-sepharose from nuclear extracts of an MS2 aptamer-tagged Rabx13 intron amoeba transformant. Thus, we probed thirty-six Entamoeba proteins corresponding to 32 cognate splicing-specific factors, including 13 DExH/D helicases required for all stages of splicing, and 12 different splicing-related helicases were identified also. Furthermore 50 additional proteins, possibly involved in co-transcriptional processes were identified, revealing the complexity of co-transcriptional splicing in Entamoeba. Some of these later factors were not previously found in splicing complex analyses. BIOLOGICAL SIGNIFICANCE Numerous facts about the splicing of the nearly 3000 introns of the Entamoeba genome have not been unraveled, particularly the splicing factors and their activities. Considering that many of such introns are located in metabolic genes, the knowledge of the splicing cues has the potential to be used to attack or control the parasite. We have found numerous new splicing-related factors which could have therapeutic benefit. We also detected all the DExH/A RNA helicases involved in splicing and splicing proofreading control. Still, Entamoeba is very inefficient in splicing fidelity, thus we may have found a possible model system to study these processes.
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Affiliation(s)
- Jesús Valdés
- Departament of Biochemistry, CINVESTAV, México D.F., Mexico.
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Emi Sato
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Yoko Chiba
- University of Tsukuba, Graduate School of Life and Environmental Sciences, Tsukuba, Japan
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Robert Winkler
- Department of Biotechnology and Biochemistry, CINVESTAV Unidad Irapuato, Irapuato, Guanajuato, Mexico
| | | | | | - Natsuki Watanabe
- University of Tsukuba, Graduate School of Life and Environmental Sciences, Tsukuba, Japan
| | - Herbert J Santos
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan; University of Tsukuba, Graduate School of Life and Environmental Sciences, Tsukuba, Japan; Institute of Biology, College of Science, University of the Philippines Diliman, Quezon City, Philippines
| | - Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
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Garrey SM, Katolik A, Prekeris M, Li X, York K, Bernards S, Fields S, Zhao R, Damha MJ, Hesselberth JR. A homolog of lariat-debranching enzyme modulates turnover of branched RNA. RNA (NEW YORK, N.Y.) 2014; 20:1337-48. [PMID: 24919400 PMCID: PMC4105757 DOI: 10.1261/rna.044602.114] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Turnover of the branched RNA intermediates and products of pre-mRNA splicing is mediated by the lariat-debranching enzyme Dbr1. We characterized a homolog of Dbr1 from Saccharomyces cerevisiae, Drn1/Ygr093w, that has a pseudo-metallophosphodiesterase domain with primary sequence homology to Dbr1 but lacks essential active site residues found in Dbr1. Whereas loss of Dbr1 results in lariat-introns failing broadly to turnover, loss of Drn1 causes low levels of lariat-intron accumulation. Conserved residues in the Drn1 C-terminal CwfJ domains, which are not present in Dbr1, are required for efficient intron turnover. Drn1 interacts with Dbr1, components of the Nineteen Complex, U2 snRNA, branched intermediates, and products of splicing. Drn1 enhances debranching catalyzed by Dbr1 in vitro, but does so without significantly improving the affinity of Dbr1 for branched RNA. Splicing carried out in in vitro extracts in the absence of Drn1 results in an accumulation of branched splicing intermediates and products released from the spliceosome, likely due to less active debranching, as well as the promiscuous release of cleaved 5'-exon. Drn1 enhances Dbr1-mediated turnover of lariat-intermediates and lariat-intron products, indicating that branched RNA turnover is regulated at multiple steps during splicing.
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Affiliation(s)
- Stephen M Garrey
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Adam Katolik
- Department of Chemistry, McGill University, Montreal, Quebec H3A 2K6, Canada
| | - Mantas Prekeris
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Xueni Li
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Kerri York
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Sarah Bernards
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Stanley Fields
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Rui Zhao
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, Quebec H3A 2K6, Canada
| | - Jay R Hesselberth
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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