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Chen S, Jiang Q, Fan J, Cheng H. Nuclear mRNA export. Acta Biochim Biophys Sin (Shanghai) 2024; 57:84-100. [PMID: 39243141 PMCID: PMC11802349 DOI: 10.3724/abbs.2024145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Accepted: 07/17/2024] [Indexed: 09/09/2024] Open
Abstract
In eukaryotic cells, gene expression begins with transcription in the nucleus, followed by the maturation of messenger RNAs (mRNAs). These mRNA molecules are then exported to the cytoplasm through the nuclear pore complex (NPC), a process that serves as a critical regulatory phase of gene expression. The export of mRNA is intricately linked to precursor mRNA (pre-mRNA) processing, ensuring that only properly processed mRNA reaches the cytoplasm. This coordination is essential, as recent studies have revealed that mRNA export factors not only assist in transport but also influence upstream processing steps, adding a layer of complexity to gene regulation. Furthermore, the export process competes with RNA processing and degradation pathways, maintaining a delicate balance vital for accurate gene expression. While these mechanisms are generally conserved across eukaryotes, significant differences exist between yeast and higher eukaryotic cells, particularly due to the more genome complexity of the latter. This review delves into the current research on mRNA export in higher eukaryotic cells, focusing on its role in the broader context of gene expression regulation and highlighting how it interacts with other gene expression processes to ensure precise and efficient gene functionality in complex organisms.
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Affiliation(s)
- Suli Chen
- Key Laboratory of Systems Health Science of Zhejiang ProvinceSchool of Life ScienceHangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou310024China
| | - Qingyi Jiang
- Key Laboratory of RNA InnovationScience and EngineeringShanghai Key Laboratory of Molecular AndrologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghai200031China
| | - Jing Fan
- Key Laboratory of RNA InnovationScience and EngineeringShanghai Key Laboratory of Molecular AndrologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghai200031China
- The Key Laboratory of Developmental Genes and Human DiseaseSchool of Life Science and TechnologySoutheast UniversityNanjing210096China
| | - Hong Cheng
- Key Laboratory of Systems Health Science of Zhejiang ProvinceSchool of Life ScienceHangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou310024China
- Key Laboratory of RNA InnovationScience and EngineeringShanghai Key Laboratory of Molecular AndrologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghai200031China
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2
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Yin Y, Shen X. Noncoding RNA-chromatin association: Functions and mechanisms. FUNDAMENTAL RESEARCH 2023; 3:665-675. [PMID: 38933302 PMCID: PMC11197541 DOI: 10.1016/j.fmre.2023.03.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/12/2023] [Accepted: 03/23/2023] [Indexed: 06/28/2024] Open
Abstract
Pervasive transcription of the mammalian genome produces hundreds of thousands of noncoding RNAs (ncRNAs). Numerous studies have suggested that some of these ncRNAs regulate multiple cellular processes and play important roles in physiological and pathological processes. Notably, a large subset of ncRNAs is enriched on chromatin and participates in regulating gene expression and the dynamics of chromatin structure and status. In this review, we summarize recent advances in the functional study of chromatin-associated ncRNAs and mechanistic insights into how these ncRNAs associate with chromatin. We also discuss the potential future challenges which still need to be overcome in this field.
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Affiliation(s)
- Yafei Yin
- Department of Cell Biology and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Yuhangtang Road, Hangzhou, Zhejiang 310058, China
| | - Xiaohua Shen
- Tsinghua-Peking Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing 100084, China
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3
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Girardini KN, Olthof AM, Kanadia RN. Introns: the "dark matter" of the eukaryotic genome. Front Genet 2023; 14:1150212. [PMID: 37260773 PMCID: PMC10228655 DOI: 10.3389/fgene.2023.1150212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/28/2023] [Indexed: 06/02/2023] Open
Abstract
The emergence of introns was a significant evolutionary leap that is a major distinguishing feature between prokaryotic and eukaryotic genomes. While historically introns were regarded merely as the sequences that are removed to produce spliced transcripts encoding functional products, increasingly data suggests that introns play important roles in the regulation of gene expression. Here, we use an intron-centric lens to review the role of introns in eukaryotic gene expression. First, we focus on intron architecture and how it may influence mechanisms of splicing. Second, we focus on the implications of spliceosomal snRNAs and their variants on intron splicing. Finally, we discuss how the presence of introns and the need to splice them influences transcription regulation. Despite the abundance of introns in the eukaryotic genome and their emerging role regulating gene expression, a lot remains unexplored. Therefore, here we refer to introns as the "dark matter" of the eukaryotic genome and discuss some of the outstanding questions in the field.
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Affiliation(s)
- Kaitlin N. Girardini
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
| | - Anouk M. Olthof
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Rahul N. Kanadia
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, United States
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4
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Khan M, Hou S, Chen M, Lei H. Mechanisms of RNA export and nuclear retention. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1755. [PMID: 35978483 DOI: 10.1002/wrna.1755] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 06/21/2022] [Accepted: 07/06/2022] [Indexed: 05/13/2023]
Abstract
With the identification of huge amount of noncoding RNAs in recent years, the concept of RNA localization has extended from traditional mRNA export to RNA export of mRNA and ncRNA as well as nuclear retention of ncRNA. This review aims to summarize the recent findings from studies on the mechanisms of export of different RNAs and nuclear retention of some lncRNAs in higher eukaryotes, with a focus on splicing-dependent TREX recruitment for the export of spliced mRNA and the sequence-dependent mechanism of mRNA export in the absence of splicing. In addition, evidence to support the involvement of m6 A modification in RNA export with the coordination between the methylase complex and TREX complex as well as sequence-dependent nuclear retention of lncRNA is recapitulated. Finally, a model of sequence-dependent RNA localization is proposed along with the many questions that remain to be answered. This article is categorized under: RNA Export and Localization > RNA Localization RNA Export and Localization > Nuclear Export/Import.
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Affiliation(s)
- Misbah Khan
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
| | - Shuai Hou
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
| | - Mo Chen
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
| | - Haixin Lei
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
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5
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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: 9] [Impact Index Per Article: 4.5] [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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6
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Suzuki H, Abe R, Shimada M, Hirose T, Hirose H, Noguchi K, Ike Y, Yasui N, Furugori K, Yamaguchi Y, Toyoda A, Suzuki Y, Yamamoto T, Saitoh N, Sato S, Tomomori-Sato C, Conaway RC, Conaway JW, Takahashi H. The 3' Pol II pausing at replication-dependent histone genes is regulated by Mediator through Cajal bodies' association with histone locus bodies. Nat Commun 2022; 13:2905. [PMID: 35614107 PMCID: PMC9133132 DOI: 10.1038/s41467-022-30632-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 05/10/2022] [Indexed: 11/09/2022] Open
Abstract
Non-polyadenylated mRNAs of replication-dependent histones (RDHs) are synthesized by RNA polymerase II (Pol II) at histone locus bodies (HLBs). HLBs frequently associate with Cajal bodies (CBs), in which 3'-end processing factors for RDH genes are enriched; however, this association's role in transcription termination of RDH genes remains unclear. Here, we show that Pol II pauses immediately upstream of transcript end sites of RDH genes and Mediator plays a role in this Pol II pausing through CBs' association with HLBs. Disruption of the Mediator docking site for Little elongation complex (LEC)-Cap binding complex (CBC)-Negative elongation factor (NELF), components of CBs, interferes with CBs' association with HLBs and 3' Pol II pausing, resulting in increased aberrant unprocessed RDH gene transcripts. Our findings suggest Mediator's involvement in CBs' association with HLBs to facilitate 3' Pol II pausing and subsequent 3'-end processing of RDH genes by supplying 3'-end processing factors.
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Affiliation(s)
- Hidefumi Suzuki
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Ryota Abe
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Miho Shimada
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Tomonori Hirose
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Hiroko Hirose
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Keisuke Noguchi
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Yoko Ike
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Nanami Yasui
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Kazuki Furugori
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Yuki Yamaguchi
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, Kanagawa, 226-8501, Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Yutaka Suzuki
- Laboratory of Systems Genomics, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8562, Japan
| | - Tatsuro Yamamoto
- Division of Cancer Biology, The Cancer Institute of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan
| | - Noriko Saitoh
- Division of Cancer Biology, The Cancer Institute of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan
| | - Shigeo Sato
- Stowers Institute for Medical Research, 1000E 50th Street, Kansas City, MO, 64110, USA
| | - Chieri Tomomori-Sato
- Stowers Institute for Medical Research, 1000E 50th Street, Kansas City, MO, 64110, USA
| | - Ronald C Conaway
- Stowers Institute for Medical Research, 1000E 50th Street, Kansas City, MO, 64110, USA.,Department of Biochemistry & Molecular Biology, University of Kansas Medical Center, Kansas City, MO, 66160, USA
| | - Joan W Conaway
- Stowers Institute for Medical Research, 1000E 50th Street, Kansas City, MO, 64110, USA.,Department of Biochemistry & Molecular Biology, University of Kansas Medical Center, Kansas City, MO, 66160, USA
| | - Hidehisa Takahashi
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan.
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7
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Guiro J, Fagbemi M, Tellier M, Zaborowska J, Barker S, Fournier M, Murphy S. CAPTURE of the Human U2 snRNA Genes Expands the Repertoire of Associated Factors. Biomolecules 2022; 12:704. [PMID: 35625631 PMCID: PMC9138887 DOI: 10.3390/biom12050704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/29/2022] [Accepted: 05/12/2022] [Indexed: 11/29/2022] Open
Abstract
In order to identify factors involved in transcription of human snRNA genes and 3' end processing of the transcripts, we have carried out CRISPR affinity purification in situ of regulatory elements (CAPTURE), which is deadCas9-mediated pull-down, of the tandemly repeated U2 snRNA genes in human cells. CAPTURE enriched many factors expected to be associated with these human snRNA genes including RNA polymerase II (pol II), Cyclin-Dependent Kinase 7 (CDK7), Negative Elongation Factor (NELF), Suppressor of Ty 5 (SPT5), Mediator 23 (MED23) and several subunits of the Integrator Complex. Suppressor of Ty 6 (SPT6); Cyclin K, the partner of Cyclin-Dependent Kinase 12 (CDK12) and Cyclin-Dependent Kinase 13 (CDK13); and SWI/SNF chromatin remodelling complex-associated SWI/SNF-related, Matrix-associated, Regulator of Chromatin (SMRC) factors were also enriched. Several polyadenylation factors, including Cleavage and Polyadenylation Specificity Factor 1 (CPSF1), Cleavage Stimulation Factors 1 and 2 (CSTF1,and CSTF2) were enriched by U2 gene CAPTURE. We have already shown by chromatin immunoprecipitation (ChIP) that CSTF2-and Pcf11 and Ssu72, which are also polyadenylation factors-are associated with the human U1 and U2 genes. ChIP-seq and ChIP-qPCR confirm the association of SPT6, Cyclin K, and CDK12 with the U2 genes. In addition, knockdown of SPT6 causes loss of subunit 3 of the Integrator Complex (INTS3) from the U2 genes, indicating a functional role in snRNA gene expression. CAPTURE has therefore expanded the repertoire of transcription and RNA processing factors associated with these genes and helped to identify a functional role for SPT6.
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Affiliation(s)
- Joana Guiro
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; (J.G.); (M.F.); (M.T.); (J.Z.); (S.B.)
| | - Mathias Fagbemi
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; (J.G.); (M.F.); (M.T.); (J.Z.); (S.B.)
| | - Michael Tellier
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; (J.G.); (M.F.); (M.T.); (J.Z.); (S.B.)
| | - Justyna Zaborowska
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; (J.G.); (M.F.); (M.T.); (J.Z.); (S.B.)
| | - Stephanie Barker
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; (J.G.); (M.F.); (M.T.); (J.Z.); (S.B.)
| | - Marjorie Fournier
- Advanced Proteomics Facility, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK;
| | - Shona Murphy
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; (J.G.); (M.F.); (M.T.); (J.Z.); (S.B.)
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8
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Caizzi L, Monteiro-Martins S, Schwalb B, Lysakovskaia K, Schmitzova J, Sawicka A, Chen Y, Lidschreiber M, Cramer P. Efficient RNA polymerase II pause release requires U2 snRNP function. Mol Cell 2021; 81:1920-1934.e9. [PMID: 33689748 DOI: 10.1016/j.molcel.2021.02.016] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 01/07/2021] [Accepted: 02/10/2021] [Indexed: 12/21/2022]
Abstract
Transcription by RNA polymerase II (Pol II) is coupled to pre-mRNA splicing, but the underlying mechanisms remain poorly understood. Co-transcriptional splicing requires assembly of a functional spliceosome on nascent pre-mRNA, but whether and how this influences Pol II transcription remains unclear. Here we show that inhibition of pre-mRNA branch site recognition by the spliceosome component U2 snRNP leads to a widespread and strong decrease in new RNA synthesis from human genes. Multiomics analysis reveals that inhibition of U2 snRNP function increases the duration of Pol II pausing in the promoter-proximal region, impairs recruitment of the pause release factor P-TEFb, and reduces Pol II elongation velocity at the beginning of genes. Our results indicate that efficient release of paused Pol II into active transcription elongation requires the formation of functional spliceosomes and that eukaryotic mRNA biogenesis relies on positive feedback from the splicing machinery to the transcription machinery.
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Affiliation(s)
- Livia Caizzi
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Sara Monteiro-Martins
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Björn Schwalb
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Kseniia Lysakovskaia
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Jana Schmitzova
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Anna Sawicka
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Ying Chen
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Michael Lidschreiber
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
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9
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Davis MR, Delaleau M, Borden KLB. Nuclear eIF4E Stimulates 3'-End Cleavage of Target RNAs. Cell Rep 2020; 27:1397-1408.e4. [PMID: 31042468 PMCID: PMC6661904 DOI: 10.1016/j.celrep.2019.04.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 02/16/2019] [Accepted: 03/29/2019] [Indexed: 11/27/2022] Open
Abstract
The eukaryotic translation initiation factor eIF4E is nuclear and cytoplasmic where it plays roles in export and translation of specific transcripts, respectively. When we were studying its mRNA export activity, we unexpectedly discovered that eIF4E drives the protein expression of elements of the 3′-end core cleavage complex involved in cleavage and polyadenylation (CPA), including CPSF3, the enzyme responsible for cleavage, as well as its co-factors CPSF1, CPSF2, CPSF4, Symplekin, WDR33, and FIP1L1. Using multiple strategies, we demonstrate that eIF4E stimulates 3′-end cleavage of selected RNAs. eIF4E physically interacts with CPSF3, CPSF1, and uncleaved target RNA, suggesting it acts directly and indirectly on the pathway. Through these effects, eIF4E can generate better substrates for its mRNA export and translation activities. Thus, we identified an unanticipated function for eIF4E in 3′-end processing of specific target RNAs, and this function could potentially affect the expression of a broad range of oncoproteins. Davis et al. demonstrate that the eukaryotic translation initiation factor eIF4E, which is usually associated with nuclear export and translation of specific transcripts, also acts in 3′-end processing of selected RNAs. Through these effects, eIF4E can generate better substrates for its export and translation activities and, thus, modulate the proteome.
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Affiliation(s)
- Margaret Rose Davis
- Institute of Research in Immunology and Cancer (IRIC), Department of Pathology and Cell Biology, Université de Montréal, Pavillon Marcelle-Coutu, 2950 Chemin de Polytechnique, Montreal, QC H3T 1J4, Canada
| | - Mildred Delaleau
- Institute of Research in Immunology and Cancer (IRIC), Department of Pathology and Cell Biology, Université de Montréal, Pavillon Marcelle-Coutu, 2950 Chemin de Polytechnique, Montreal, QC H3T 1J4, Canada
| | - Katherine L B Borden
- Institute of Research in Immunology and Cancer (IRIC), Department of Pathology and Cell Biology, Université de Montréal, Pavillon Marcelle-Coutu, 2950 Chemin de Polytechnique, Montreal, QC H3T 1J4, Canada.
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10
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Sun C. The SF3b complex: splicing and beyond. Cell Mol Life Sci 2020; 77:3583-3595. [PMID: 32140746 PMCID: PMC7452928 DOI: 10.1007/s00018-020-03493-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/13/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022]
Abstract
The SF3b complex is an intrinsic component of the functional U2 small nuclear ribonucleoprotein (snRNP). As U2 snRNP enters nuclear pre-mRNA splicing, SF3b plays key roles in recognizing the branch point sequence (BPS) and facilitating spliceosome assembly and activation. Since the discovery of SF3b, substantial progress has been made in elucidating its molecular mechanism during splicing. In addition, numerous recent studies indicate that SF3b and its components are engaged in various molecular and cellular events that are beyond the canonical role in splicing. This review summarizes the current knowledge on the SF3b complex and highlights its multiple roles in splicing and beyond.
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Affiliation(s)
- Chengfu Sun
- Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, 610500, China.
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11
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van der Feltz C, Hoskins AA. Structural and functional modularity of the U2 snRNP in pre-mRNA splicing. Crit Rev Biochem Mol Biol 2019; 54:443-465. [PMID: 31744343 DOI: 10.1080/10409238.2019.1691497] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The U2 small nuclear ribonucleoprotein (snRNP) is an essential component of the spliceosome, the cellular machine responsible for removing introns from precursor mRNAs (pre-mRNAs) in all eukaryotes. U2 is an extraordinarily dynamic splicing factor and the most frequently mutated in cancers. Cryo-electron microscopy (cryo-EM) has transformed our structural and functional understanding of the role of U2 in splicing. In this review, we synthesize these and other data with respect to a view of U2 as an assembly of interconnected functional modules. These modules are organized by the U2 small nuclear RNA (snRNA) for roles in spliceosome assembly, intron substrate recognition, and protein scaffolding. We describe new discoveries regarding the structure of U2 components and how the snRNP undergoes numerous conformational and compositional changes during splicing. We specifically highlight large scale movements of U2 modules as the spliceosome creates and rearranges its active site. U2 serves as a compelling example for how cellular machines can exploit the modular organization and structural plasticity of an RNP.
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Affiliation(s)
| | - Aaron A Hoskins
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
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12
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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: 22] [Impact Index Per Article: 3.7] [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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13
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Abstract
To ensure efficient and accurate gene expression, pre-mRNA processing and mRNA export need to be balanced. However, how this balance is ensured remains largely unclear. Here, we found that SF3b, a component of U2 snRNP that participates in splicing and 3' processing of pre-mRNAs, interacts with the key mRNA export adaptor THO in vivo and in vitro. Depletion of SF3b reduces THO binding with the mRNA and causes nuclear mRNA retention. Consistently, introducing SF3b binding sites into the mRNA enhances THO recruitment and nuclear export in a dose-dependent manner. These data demonstrate a role of SF3b in promoting mRNA export. In support of this role, SF3b binds with mature mRNAs in the cells. Intriguingly, disruption of U2 snRNP by using a U2 antisense morpholino oligonucleotide does not inhibit, but promotes, the role of SF3b in mRNA export as a result of enhanced SF3b-THO interaction and THO recruitment to the mRNA. Together, our study uncovers a U2-snRNP-independent role of SF3b in mRNA export and suggests that SF3b contributes to balancing pre-mRNA processing and mRNA export.
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14
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Mei Q, Huang J, Chen W, Tang J, Xu C, Yu Q, Cheng Y, Ma L, Yu X, Li S. Regulation of DNA replication-coupled histone gene expression. Oncotarget 2017; 8:95005-95022. [PMID: 29212286 PMCID: PMC5706932 DOI: 10.18632/oncotarget.21887] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 09/20/2017] [Indexed: 12/21/2022] Open
Abstract
The expression of core histone genes is cell cycle regulated. Large amounts of histones are required to restore duplicated chromatin during S phase when DNA replication occurs. Over-expression and excess accumulation of histones outside S phase are toxic to cells and therefore cells need to restrict histone expression to S phase. Misregulation of histone gene expression leads to defects in cell cycle progression, genome stability, DNA damage response and transcriptional regulation. Here, we discussed the factors involved in histone gene regulation as well as the underlying mechanism. Understanding the histone regulation mechanism will shed lights on elucidating the side effects of certain cancer chemotherapeutic drugs and developing potential biomarkers for tumor cells.
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Affiliation(s)
- Qianyun Mei
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Junhua Huang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Wanping Chen
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China.,Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Jie Tang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Chen Xu
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Qi Yu
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Ying Cheng
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Lixin Ma
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China.,Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Xilan Yu
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China.,Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Shanshan Li
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China.,Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
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15
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Brodersen MML, Lampert F, Barnes CA, Soste M, Piwko W, Peter M. CRL4(WDR23)-Mediated SLBP Ubiquitylation Ensures Histone Supply during DNA Replication. Mol Cell 2017; 62:627-35. [PMID: 27203182 DOI: 10.1016/j.molcel.2016.04.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 03/11/2016] [Accepted: 04/15/2016] [Indexed: 01/07/2023]
Abstract
To maintain genome integrity and epigenetic information, mammalian cells must carefully coordinate the supply and deposition of histones during DNA replication. Here we report that the CUL4 E3 ubiquitin ligase complex CRL4(WDR23) directly regulates the stem-loop binding protein (SLBP), which orchestrates the life cycle of histone transcripts including their stability, maturation, and translation. Lack of CRL4(WDR23) activity is characterized by depletion of histones resulting in inhibited DNA replication and a severe slowdown of growth in human cells. Detailed analysis revealed that CRL4(WDR23) is required for efficient histone mRNA 3' end processing to produce mature histone mRNAs for translation. CRL4(WDR23) binds and ubiquitylates SLBP in vitro and in vivo, and this modification activates SLBP function in histone mRNA 3' end processing without affecting its protein levels. Together, these results establish a mechanism by which CUL4 regulates DNA replication and possible additional chromatin transactions by controlling the concerted expression of core histones.
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Affiliation(s)
- Mia M L Brodersen
- Institute of Biochemistry, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland.
| | - Fabienne Lampert
- Institute of Biochemistry, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Christopher A Barnes
- Institute of Biochemistry, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Martin Soste
- Institute of Biochemistry, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Wojciech Piwko
- Institute of Biochemistry, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Matthias Peter
- Institute of Biochemistry, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland.
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16
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Lampert F, Brodersen MML, Peter M. Guard the guardian: A CRL4 ligase stands watch over histone production. Nucleus 2017; 8:134-143. [PMID: 28072566 DOI: 10.1080/19491034.2016.1276143] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Histones are evolutionarily conserved proteins that together with DNA constitute eukaryotic chromatin in a defined stoichiometry. Core histones are dynamic scaffolding proteins that undergo a myriad of post-translational modifications, which selectively engage chromosome condensation, replication, transcription and DNA damage repair. Cullin4-RING ubiquitin E3 ligases are known to hold pivotal roles in a wide spectrum of chromatin biology ranging from chromatin remodeling and transcriptional repression, to sensing of cytotoxic DNA lesions. Our recent work uncovers an unexpected function of a CRL4 ligase upstream of these processes in promoting histone biogenesis. The CRL4WDR23 ligase directly controls the activity of the stem-loop binding protein (SLBP), which orchestrates elemental steps of canonical histone transcript metabolism. We demonstrate that non-proteolytic ubiquitination of SLBP ensures sufficient histone reservoirs during DNA replication and is vital for genome integrity and cellular fitness.
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Affiliation(s)
| | - Mia M L Brodersen
- a Institute of Biochemistry, ETH Zurich , Zürich , Switzerland.,b nspm. ltd. , Meggen , Switzerland
| | - Matthias Peter
- a Institute of Biochemistry, ETH Zurich , Zürich , Switzerland
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17
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Sawyer IA, Sturgill D, Sung MH, Hager GL, Dundr M. Cajal body function in genome organization and transcriptome diversity. Bioessays 2016; 38:1197-1208. [PMID: 27767214 DOI: 10.1002/bies.201600144] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Nuclear bodies contribute to non-random organization of the human genome and nuclear function. Using a major prototypical nuclear body, the Cajal body, as an example, we suggest that these structures assemble at specific gene loci located across the genome as a result of high transcriptional activity. Subsequently, target genes are physically clustered in close proximity in Cajal body-containing cells. However, Cajal bodies are observed in only a limited number of human cell types, including neuronal and cancer cells. Ultimately, Cajal body depletion perturbs splicing kinetics by reducing target small nuclear RNA (snRNA) transcription and limiting the levels of spliceosomal snRNPs, including their modification and turnover following each round of RNA splicing. As such, Cajal bodies are capable of shaping the chromatin interaction landscape and the transcriptome by influencing spliceosome kinetics. Future studies should concentrate on characterizing the direct influence of Cajal bodies upon snRNA gene transcriptional dynamics. Also see the video abstract here.
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Affiliation(s)
- Iain A Sawyer
- Department of Cell Biology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA.,Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - David Sturgill
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Myong-Hee Sung
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Gordon L Hager
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Miroslav Dundr
- Department of Cell Biology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
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18
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Stegeman R, Spreacker PJ, Swanson SK, Stephenson R, Florens L, Washburn MP, Weake VM. The Spliceosomal Protein SF3B5 is a Novel Component of Drosophila SAGA that Functions in Gene Expression Independent of Splicing. J Mol Biol 2016; 428:3632-49. [PMID: 27185460 PMCID: PMC5011000 DOI: 10.1016/j.jmb.2016.05.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/19/2016] [Accepted: 05/08/2016] [Indexed: 12/16/2022]
Abstract
The interaction between splicing factors and the transcriptional machinery provides an intriguing link between the coupled processes of transcription and splicing. Here, we show that the two components of the SF3B complex, SF3B3 and SF3B5, that form part of the U2 small nuclear ribonucleoprotein particle (snRNP) are also subunits of the Spt-Ada-Gcn5 acetyltransferase (SAGA) transcriptional coactivator complex in Drosophila melanogaster. Whereas SF3B3 had previously been identified as a human SAGA subunit, SF3B5 had not been identified as a component of SAGA in any species. We show that SF3B3 and SF3B5 bind to SAGA independent of RNA and interact with multiple SAGA subunits including Sgf29 and Spt7 in a yeast two-hybrid assay. Through analysis of sf3b5 mutant flies, we show that SF3B5 is necessary for proper development and cell viability but not for histone acetylation. Although SF3B5 does not appear to function in SAGA's histone-modifying activities, SF3B5 is still required for expression of a subset of SAGA-regulated genes independent of splicing. Thus, our data support an independent function of SF3B5 in SAGA's transcription coactivator activity that is separate from its role in splicing.
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Affiliation(s)
- Rachel Stegeman
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Peyton J Spreacker
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Selene K Swanson
- Stowers Institute for Medical Research, 1000 E. 50th St., Kansas City, MO 64110, USA
| | - Robert Stephenson
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Laurence Florens
- Stowers Institute for Medical Research, 1000 E. 50th St., Kansas City, MO 64110, USA
| | - Michael P Washburn
- Stowers Institute for Medical Research, 1000 E. 50th St., Kansas City, MO 64110, USA; Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Vikki M Weake
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA; Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA.
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19
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Török A, Schiffer PH, Schnitzler CE, Ford K, Mullikin JC, Baxevanis AD, Bacic A, Frank U, Gornik SG. The cnidarian Hydractinia echinata employs canonical and highly adapted histones to pack its DNA. Epigenetics Chromatin 2016; 9:36. [PMID: 27602058 PMCID: PMC5011920 DOI: 10.1186/s13072-016-0085-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/24/2016] [Indexed: 11/25/2022] Open
Abstract
Background Cnidarians are a group of early branching animals including corals, jellyfish and hydroids that are renowned for their high regenerative ability, growth plasticity and longevity. Because cnidarian genomes are conventional in terms of protein-coding genes, their remarkable features are likely a consequence of epigenetic regulation. To facilitate epigenetics research in cnidarians, we analysed the histone complement of the cnidarian model organism Hydractinia echinata using phylogenomics, proteomics, transcriptomics and mRNA in situ hybridisations. Results We find that the Hydractinia genome encodes 19 histones and analyse their spatial expression patterns, genomic loci and replication-dependency. Alongside core and other replication-independent histone variants, we find several histone replication-dependent variants, including a rare replication-dependent H3.3, a female germ cell-specific H2A.X and an unusual set of five H2B variants, four of which are male germ cell-specific. We further confirm the absence of protamines in Hydractinia. Conclusions Since no protamines are found in hydroids, we suggest that the novel H2B variants are pivotal for sperm DNA packaging in this class of Cnidaria. This study adds to the limited number of full histone gene complements available in animals and sets a comprehensive framework for future studies on the role of histones and their post-translational modifications in cnidarian epigenetics. Finally, it provides insight into the evolution of spermatogenesis. Electronic supplementary material The online version of this article (doi:10.1186/s13072-016-0085-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anna Török
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Philipp H Schiffer
- Genetics Environment and Evolution, University College London, London, UK
| | - Christine E Schnitzler
- Division of Intramural Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892 USA ; Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080 USA
| | - Kris Ford
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080 USA ; Australian Research Council Centre of Excellence in Plant Cell Walls, School of Biosciences, The University of Melbourne, Parkville, VIC 3010 Australia
| | - James C Mullikin
- Division of Intramural Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892 USA ; NIH Intramural Sequencing Center, National Human Genome Research Institute, National Institutes of Health, Rockville, MD 20852 USA
| | - Andreas D Baxevanis
- Division of Intramural Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Antony Bacic
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of Biosciences, The University of Melbourne, Parkville, VIC 3010 Australia
| | - Uri Frank
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Sebastian G Gornik
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland, Galway, Ireland
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20
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Romeo V, Schümperli D. Cycling in the nucleus: regulation of RNA 3′ processing and nuclear organization of replication-dependent histone genes. Curr Opin Cell Biol 2016; 40:23-31. [DOI: 10.1016/j.ceb.2016.01.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 01/27/2016] [Accepted: 01/30/2016] [Indexed: 12/01/2022]
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21
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Abstract
In metazoan the 3′-end processing of histone mRNAs is a conserved process involving the concerted action of many protein factors and the non-coding U7 snRNA. Recently, we identified that the processing of histone pre-mRNAs is promoted by an additional ncRNA, the Y3-derived Y3** RNA. U7 modulates the association of the U7 snRNP whereas Y3** promotes recruitment of CPSF (cleavage and polyadenylation specific factor) proteins to nascent histone transcripts at histone locus bodies (HLBs) in mammals. This enhances the 3′-end cleavage of nascent histone pre-mRNAs and modulates HLB assembly. Here we discuss new insights in the role of ncRNAs in the spatiotemporal control of histone synthesis. We propose that ncRNAs scaffold the formation of functional protein-RNA complexes and their sequential deposition on nascent histone pre-mRNAs at HLBs. These findings add to the multiple roles of ncRNAs in controlling gene expression and may provide new avenues for targeting histone synthesis in cancer.
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Affiliation(s)
- Marcel Köhn
- a Institute of Molecular Medicine, Section for Molecular Cell Biology, Faculty of Medicine, Martin-Luther-University Halle Wittenberg, ZAMED , Halle , Germany
| | - Stefan Hüttelmaier
- a Institute of Molecular Medicine, Section for Molecular Cell Biology, Faculty of Medicine, Martin-Luther-University Halle Wittenberg, ZAMED , Halle , Germany
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22
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Lu Z, Guan X, Schmidt CA, Matera AG. RIP-seq analysis of eukaryotic Sm proteins identifies three major categories of Sm-containing ribonucleoproteins. Genome Biol 2014; 15:R7. [PMID: 24393626 PMCID: PMC4053861 DOI: 10.1186/gb-2014-15-1-r7] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 01/07/2014] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Sm proteins are multimeric RNA-binding factors, found in all three domains of life. Eukaryotic Sm proteins, together with their associated RNAs, form small ribonucleoprotein (RNP) complexes important in multiple aspects of gene regulation. Comprehensive knowledge of the RNA components of Sm RNPs is critical for understanding their functions. RESULTS We developed a multi-targeting RNA-immunoprecipitation sequencing (RIP-seq) strategy to reliably identify Sm-associated RNAs from Drosophila ovaries and cultured human cells. Using this method, we discovered three major categories of Sm-associated transcripts: small nuclear (sn)RNAs, small Cajal body (sca)RNAs and mRNAs. Additional RIP-PCR analysis showed both ubiquitous and tissue-specific interactions. We provide evidence that the mRNA-Sm interactions are mediated by snRNPs, and that one of the mechanisms of interaction is via base pairing. Moreover, the Sm-associated mRNAs are mature, indicating a splicing-independent function for Sm RNPs. CONCLUSIONS This study represents the first comprehensive analysis of eukaryotic Sm-containing RNPs, and provides a basis for additional functional analyses of Sm proteins and their associated snRNPs outside of the context of pre-mRNA splicing. Our findings expand the repertoire of eukaryotic Sm-containing RNPs and suggest new functions for snRNPs in mRNA metabolism.
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Affiliation(s)
- Zhipeng Lu
- Departments of Biology and Genetics, Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599-3280, USA
| | - Xiaojun Guan
- Center for Bioinformatics, University of North Carolina, Chapel Hill, NC 27599-3280, USA
- Current address: Sequenom, San Diego, CA 92121, USA
| | - Casey A Schmidt
- Curriculum in Genetics & Molecular Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA
| | - A Gregory Matera
- Departments of Biology and Genetics, Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599-3280, USA
- Curriculum in Genetics & Molecular Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA
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23
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Langemeier J, Radtke M, Bohne J. U1 snRNP-mediated poly(A) site suppression: beneficial and deleterious for mRNA fate. RNA Biol 2013; 10:180-4. [PMID: 23324605 DOI: 10.4161/rna.23314] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The spliceosomal component U1snRNP commits pre-mRNAs to the splicing pathway. Recently, a nuclear RNA surveillance function has been ascribed to U1, namely the suppression of intronic polyadenylation sites. This surveillance holds regulatory potential as it alters the 3' ends of certain receptor tyrosine kinase mRNAs. However, suppression of 3' end processing by U1 snRNP is also the cause of a severe genetic disorder. We described a 3'UTR point mutation creating a 5'SS leading to U1-mediated suppression of 3' end formation. Thus, the inhibitory function of U1 is both beneficial and deleterious where misled. The exact mechanism of how U1 interferes with 3' end processing remains unclear. According to our data, U1 snRNP already interferes with cleavage or poly(A) site selection instead of directly inhibiting poly(A) polymerase as previously assumed. Here, we present alternative models for U1-mediated poly(A) site suppression and discuss the implications for RNA quality control and disease-related mutations.
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Affiliation(s)
- Jörg Langemeier
- Institute for Virology, Hannover Medical School, Hannover, Germany
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24
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Abstract
Several bacterial fermentation products and their synthetic derivatives display antitumour activities and bind tightly to components of the spliceosome, which is the complex molecular machinery involved in the removal of introns from mRNA precursors in eukaryotic cells. The drugs alter gene expression, including alternative splicing, of genes that are important for cancer progression. A flurry of recent reports has revealed that genes encoding splicing factors, including the drug target splicing factor 3B subunit 1 (SF3B1), are among the most highly mutated in various haematological malignancies such as chronic lymphocytic leukaemia and myelodysplastic syndromes. These observations highlight the role of splicing factors in cancer and suggest that an understanding of the molecular effects of drugs targeting these proteins could open new perspectives for studies of the spliceosome and its role in cancer progression, and for the development of novel antitumour therapies.
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25
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Mandalos N, Saridaki M, Harper JL, Kotsoni A, Yang P, Economides AN, Remboutsika E. Application of a novel strategy of engineering conditional alleles to a single exon gene, Sox2. PLoS One 2012; 7:e45768. [PMID: 23029233 PMCID: PMC3459942 DOI: 10.1371/journal.pone.0045768] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Accepted: 08/20/2012] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The Conditional by Inversion (COIN) method for engineering conditional alleles relies on an invertible optimized gene trap-like element, the COIN module, for imparting conditionality. The COIN module contains an optimized 3' splice site-polyadenylation signal pair, but is inserted antisense to the target gene and therefore does not alter transcription, until it is inverted by Cre recombinase. In order to make COIN applicable to all protein-coding genes, the COIN module has been engineered within an artificial intron, enabling insertion into an exon. METHODOLOGY/PRINCIPAL FINDINGS Therefore, theoretically, the COIN method should be applicable to single exon genes, and to test this idea we engineered a COIN allele of Sox2. This single exon gene presents additional design challenges, in that its proximal promoter and coding region are entirely contained within a CpG island, and are also spanned by an overlapping transcript, Sox2Ot, which contains mmu-miR1897. Here, we show that despite disruption of the CpG island by the COIN module intron, the COIN allele of Sox2 (Sox2(COIN)) is phenotypically wild type, and also does not interfere with expression of Sox2Ot and miR1897. Furthermore, the inverted COIN allele of Sox2, Sox2(INV) is functionally null, as homozygotes recapitulate the phenotype of Sox2(βgeo/βgeo) mice, a well-characterized Sox2 null. Lastly, the benefit of the eGFP marker embedded in the COIN allele is demonstrated as it mirrors the expression pattern of Sox2. CONCLUSIONS/SIGNIFICANCE Our results demonstrate the applicability of the COIN technology as a method of choice for targeting single exon genes.
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Affiliation(s)
- Nikolaos Mandalos
- Stem Cell Biology Laboratory, Institute of Molecular Biology and Genetics, Biomedical Sciences Research Centre “Alexander Fleming”, Vari, Greece
| | - Marannia Saridaki
- Stem Cell Biology Laboratory, Institute of Molecular Biology and Genetics, Biomedical Sciences Research Centre “Alexander Fleming”, Vari, Greece
| | - Jessica Lea Harper
- Stem Cell Biology Laboratory, Institute of Molecular Biology and Genetics, Biomedical Sciences Research Centre “Alexander Fleming”, Vari, Greece
- Regeneron Pharmaceuticals Inc., Tarrytown, New York, United States of America
| | - Anastasia Kotsoni
- Stem Cell Biology Laboratory, Institute of Molecular Biology and Genetics, Biomedical Sciences Research Centre “Alexander Fleming”, Vari, Greece
| | - Peter Yang
- Regeneron Pharmaceuticals Inc., Tarrytown, New York, United States of America
| | - Aris N. Economides
- Regeneron Pharmaceuticals Inc., Tarrytown, New York, United States of America
| | - Eumorphia Remboutsika
- Stem Cell Biology Laboratory, Institute of Molecular Biology and Genetics, Biomedical Sciences Research Centre “Alexander Fleming”, Vari, Greece
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26
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Langemeier J, Schrom EM, Rabner A, Radtke M, Zychlinski D, Saborowski A, Bohn G, Mandel-Gutfreund Y, Bodem J, Klein C, Bohne J. A complex immunodeficiency is based on U1 snRNP-mediated poly(A) site suppression. EMBO J 2012; 31:4035-44. [PMID: 22968171 DOI: 10.1038/emboj.2012.252] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 08/10/2012] [Indexed: 01/01/2023] Open
Abstract
Biallelic mutations in the untranslated regions (UTRs) of mRNAs are rare causes for monogenetic diseases whose mechanisms remain poorly understood. We investigated a 3'UTR mutation resulting in a complex immunodeficiency syndrome caused by decreased mRNA levels of p14/robld3 by a previously unknown mechanism. Here, we show that the mutation creates a functional 5' splice site (SS) and that its recognition by the spliceosomal component U1 snRNP causes p14 mRNA suppression in the absence of splicing. Histone processing signals are able to rescue p14 expression. Therefore, the mutation interferes only with canonical poly(A)-site 3' end processing. Our data suggest that U1 snRNP inhibits cleavage or poly(A) site recognition. This is the first description of a 3'UTR mutation that creates a functional 5'SS causative of a monogenetic disease. Moreover, our data endorse the recently described role of U1 snRNP in suppression of intronic poly(A) sites, which is here deleterious for p14 mRNA biogenesis.
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Affiliation(s)
- Jörg Langemeier
- Cell and Virus Genetics Group, Institute for Virology, Hannover Medical School, Hannover, Germany
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27
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Abstract
Histone proteins are essential for the packaging of DNA into chromosomes. Histone gene expression is cell-cycle-regulated and coupled to DNA replication. Control of histone gene expression occurs at the transcriptional and post-transcriptional level and ensures that a fine balance between histone abundance and DNA replication is maintained for the correct packaging of newly replicated DNA into chromosomes. In the present paper, we review histone gene expression, highlighting the control mechanisms and key molecules involved in this process.
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28
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Abstract
The intron–exon architecture of many eukaryotic genes raises the intriguing question of whether this unique organization serves any function, or is it simply a result of the spread of functionless introns in eukaryotic genomes. In this review, we show that introns in contemporary species fulfill a broad spectrum of functions, and are involved in virtually every step of mRNA processing. We propose that this great diversity of intronic functions supports the notion that introns were indeed selfish elements in early eukaryotes, but then independently gained numerous functions in different eukaryotic lineages. We suggest a novel criterion of evolutionary conservation, dubbed intron positional conservation, which can identify functional introns.
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Affiliation(s)
- Michal Chorev
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem Jerusalem, Israel
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29
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Zhang M, Lam TT, Tonelli M, Marzluff WF, Thapar R. Interaction of the histone mRNA hairpin with stem-loop binding protein (SLBP) and regulation of the SLBP-RNA complex by phosphorylation and proline isomerization. Biochemistry 2012; 51:3215-31. [PMID: 22439849 DOI: 10.1021/bi2018255] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In metazoans, the majority of histone proteins are generated from replication-dependent histone mRNAs. These mRNAs are unique in that they are not polyadenylated but have a stem-loop structure in their 3' untranslated region. An early event in 3' end formation of histone mRNAs is the binding of stem-loop binding protein (SLBP) to the stem-loop structure. Here we provide insight into the mechanism by which SLBP contacts the histone mRNA. There are two binding sites in the SLBP RNA binding domain for the histone mRNA hairpin. The first binding site (Glu129-Val158) consists of a helix-turn-helix motif that likely recognizes the unpaired uridines in the loop of the histone hairpin and, upon binding, destabilizes the first G-C base pair at the base of the stem. The second binding site lies between residues Arg180 and Pro200, which appears to recognize the second G-C base pair from the base of the stem and possibly regions flanking the stem-loop structure. We show that the SLBP-histone mRNA complex is regulated by threonine phosphorylation and proline isomerization in a conserved TPNK sequence that lies between the two binding sites. Threonine phosphorylation increases the affinity of SLBP for histone mRNA by slowing the off rate for complex dissociation, whereas the adjacent proline acts as a critical hinge that may orient the second binding site for formation of a stable SLBP-histone mRNA complex. The nuclear magnetic resonance and kinetic studies presented here provide a framework for understanding how SLBP recognizes histone mRNA and highlight possible structural roles of phosphorylation and proline isomerization in RNA binding proteins in remodeling ribonucleoprotein complexes.
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Affiliation(s)
- Minyou Zhang
- Hauptman-Woodward Medical Research Institute, Buffalo, New York 14203, United States
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30
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Ruepp MD, Schümperli D, Barabino SML. mRNA 3' end processing and more--multiple functions of mammalian cleavage factor I-68. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 2:79-91. [PMID: 21956970 DOI: 10.1002/wrna.35] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The formation of defined 3(') ends is an important step in the biogenesis of mRNAs. In eukaryotic cells, all mRNA 3(') ends are generated by endonucleolytic cleavage of primary transcripts in reactions that are essentially posttranscriptional. Nevertheless, 3(') end formation is tightly connected to transcription in vivo, and a link with mRNA export to the cytoplasm has been postulated. Here, we briefly review the current knowledge about the two types of mRNA 3(') end processing reactions, cleavage/polyadenylation and histone RNA processing. We then focus on factors shared between these two reactions. In particular, we discuss evidence for new functions of the mammalian cleavage factor I subunit CF I(m) 68 in histone RNA 3(') processing and in the export of mature mRNAs from the nucleus to the cytoplasm.
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Affiliation(s)
- Marc-David Ruepp
- Institute of Cell Biology, University of Bern, Bern, Switzerland
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31
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Rajendra T, Praveen K, Matera AG. Genetic analysis of nuclear bodies: from nondeterministic chaos to deterministic order. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2011; 75:365-74. [PMID: 21467138 PMCID: PMC4062921 DOI: 10.1101/sqb.2010.75.043] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The eukaryotic nucleus is a congested place, and macromolecular crowding is thought to have an important role in increasing the relative concentrations of nuclear proteins, thereby accelerating the rates of biochemical reactions. Crowding is also thought to provide the environment needed for formation of nuclear bodies/subcompartments, such as the Cajal body (CB) and the histone locus body (HLB), via self-organization. In this chapter, we contrast the theories of stochastic self-organization and hierarchical self-organization in their application to nuclear body assembly, using CBs and HLBs as paradigms. Genetic ablation studies in Drosophila on components of CBs and HLBs have revealed an order to the assembly of these structures that is suggestive of a hierarchical model of self-organization. These studies also show that functions attributed to the nuclear bodies are largely unaffected in their absence, reinforcing an emerging theme in the field that the purpose of these subdomains may be to enhance the efficiency and specificity of reactions.
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Affiliation(s)
- T.K. Rajendra
- Departments of Biology and Genetics, Program in Molecular Biology & Biotechnology, Lineberger Comprehensive Cancer Center University of North Carolina, Chapel Hill, NC 27599
| | - Kavita Praveen
- Departments of Biology and Genetics, Program in Molecular Biology & Biotechnology, Lineberger Comprehensive Cancer Center University of North Carolina, Chapel Hill, NC 27599
| | - A. Gregory Matera
- Departments of Biology and Genetics, Program in Molecular Biology & Biotechnology, Lineberger Comprehensive Cancer Center University of North Carolina, Chapel Hill, NC 27599
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32
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Kaida D, Berg MG, Younis I, Kasim M, Singh LN, Wan L, Dreyfuss G. U1 snRNP protects pre-mRNAs from premature cleavage and polyadenylation. Nature 2010; 468:664-8. [PMID: 20881964 PMCID: PMC2996489 DOI: 10.1038/nature09479] [Citation(s) in RCA: 509] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Accepted: 09/09/2010] [Indexed: 11/10/2022]
Abstract
In eukaryotes, U1 small nuclear ribonucleoprotein (snRNP) forms spliceosomes in equal stoichiometry with U2, U4, U5 and U6 snRNPs; however, its abundance in human far exceeds that of the other snRNPs. Here we used antisense morpholino oligonucleotide to U1 snRNA to achieve functional U1 snRNP knockdown in HeLa cells, and identified accumulated unspliced pre-mRNAs by genomic tiling microarrays. In addition to inhibiting splicing, U1 snRNP knockdown caused premature cleavage and polyadenylation in numerous pre-mRNAs at cryptic polyadenylation signals, frequently in introns near (<5 kilobases) the start of the transcript. This did not occur when splicing was inhibited with U2 snRNA antisense morpholino oligonucleotide or the U2-snRNP-inactivating drug spliceostatin A unless U1 antisense morpholino oligonucleotide was also included. We further show that U1 snRNA-pre-mRNA base pairing was required to suppress premature cleavage and polyadenylation from nearby cryptic polyadenylation signals located in introns. These findings reveal a critical splicing-independent function for U1 snRNP in protecting the transcriptome, which we propose explains its overabundance.
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Affiliation(s)
- Daisuke Kaida
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6148, USA
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33
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Koodathingal P, Novak T, Piccirilli JA, Staley JP. The DEAH box ATPases Prp16 and Prp43 cooperate to proofread 5' splice site cleavage during pre-mRNA splicing. Mol Cell 2010; 39:385-95. [PMID: 20705241 DOI: 10.1016/j.molcel.2010.07.014] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 03/31/2010] [Accepted: 06/03/2010] [Indexed: 12/24/2022]
Abstract
To investigate the mechanisms underlying accurate pre-mRNA splicing, we developed an in vitro assay sensitive to proofreading of 5' splice site cleavage. We inactivated spliceosomes by disrupting a metal-ligand interaction at the catalytic center and discovered that, when the DEAH box ATPase Prp16 was disabled, these spliceosomes catalyzed 5' splice site cleavage but at a reduced rate. Although Prp16 does not promote splicing of a genuine substrate until after 5' splice site cleavage, we found that Prp16 can associate with spliceosomes before 5' splice site cleavage, consistent with a role for Prp16 in proofreading 5' splice site cleavage. We established that Prp16-mediated rejection is reversible, necessitating a downstream discard pathway that we found requires the DEAH box ATPase Prp43, a spliceosome disassembly factor. These data indicate that spliceosomes distinguish slow substrates and that the mechanisms for establishing the fidelity of 5' splice site cleavage and exon ligation share a common ATP-dependent framework.
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Affiliation(s)
- Prakash Koodathingal
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
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34
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Spiluttini B, Gu B, Belagal P, Smirnova AS, Nguyen VT, Hébert C, Schmidt U, Bertrand E, Darzacq X, Bensaude O. Splicing-independent recruitment of U1 snRNP to a transcription unit in living cells. J Cell Sci 2010; 123:2085-93. [PMID: 20519584 DOI: 10.1242/jcs.061358] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Numerous non-coding RNAs are known to be involved in the regulation of gene expression. In this work, we analyzed RNAs that co-immunoprecipitated with human RNA polymerase II from mitotic cell extracts and identified U1 small nuclear RNA (snRNA) as a major species. To investigate a possible splicing-independent recruitment of U1 snRNA to transcription units, we established cell lines having integrated a reporter gene containing a functional intron or a splicing-deficient construction. Recruitment of U snRNAs and some splicing factors to transcription sites was evaluated using fluorescence in situ hybridization (FISH) and immunofluorescence. To analyze imaging data, we developed a quantitative procedure, 'radial analysis', based on averaging data from multiple fluorescence images. The major splicing snRNAs (U2, U4 and U6 snRNAs) as well as the U2AF65 and SC35 splicing factors were found to be recruited only to transcription units containing a functional intron. By contrast, U1 snRNA, the U1-70K (also known as snRNP70) U1-associated protein as well as the ASF/SF2 (also known as SFRS1) serine/arginine-rich (SR) protein were efficiently recruited both to normally spliced and splicing-deficient transcription units. The constitutive association of U1 small nuclear ribonucleoprotein (snRNP) with the transcription machinery might play a role in coupling transcription with pre-mRNA maturation.
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Affiliation(s)
- Béatrice Spiluttini
- Ecole Normale Supérieure, Institut de Biologie de l'ENS, IBENS, Paris, France
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35
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Ruepp MD, Vivarelli S, Pillai RS, Kleinschmidt N, Azzouz TN, Barabino SML, Schümperli D. The 68 kDa subunit of mammalian cleavage factor I interacts with the U7 small nuclear ribonucleoprotein and participates in 3'-end processing of animal histone mRNAs. Nucleic Acids Res 2010; 38:7637-50. [PMID: 20634199 PMCID: PMC2995043 DOI: 10.1093/nar/gkq613] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Metazoan replication-dependent histone pre-mRNAs undergo a unique 3′-cleavage reaction which does not result in mRNA polyadenylation. Although the cleavage site is defined by histone-specific factors (hairpin binding protein, a 100-kDa zinc-finger protein and the U7 snRNP), a large complex consisting of cleavage/polyadenylation specificity factor, two subunits of cleavage stimulation factor and symplekin acts as the effector of RNA cleavage. Here, we report that yet another protein involved in cleavage/polyadenylation, mammalian cleavage factor I 68-kDa subunit (CF Im68), participates in histone RNA 3′-end processing. CF Im68 was found in a highly purified U7 snRNP preparation. Its interaction with the U7 snRNP depends on the N-terminus of the U7 snRNP protein Lsm11, known to be important for histone RNA processing. In vivo, both depletion and overexpression of CF Im68 cause significant decreases in processing efficiency. In vitro 3′-end processing is slightly stimulated by the addition of low amounts of CF Im68, but inhibited by high amounts or by anti-CF Im68 antibody. Finally, immunoprecipitation of CF Im68 results in a strong enrichment of histone pre-mRNAs. In contrast, the small CF Im subunit, CF Im25, does not appear to be involved in histone RNA processing.
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Affiliation(s)
- Marc-David Ruepp
- Institute of Cell Biology, University of Bern, CH-3012 Bern, Switzerland
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36
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Abstract
To promote fidelity in nuclear pre-mRNA splicing, the spliceosome rejects and discards suboptimal substrates that have engaged the spliceosome. Whereas DExD/H box ATPases have been implicated in rejecting suboptimal substrates, the mechanism for discarding suboptimal substrates has remained obscure. Corroborating evidence that suboptimal, mutated lariat intermediates can be exported to the cytoplasm for turnover, we have found that the ribosome can translate mutated lariat intermediates. By glycerol gradient analysis, we have found that the spliceosome can dissociate mutated lariat intermediates in vivo in a manner that requires the DEAH box ATPase Prp43p. Through an in vitro assay, we demonstrate that Prp43p promotes the discard of suboptimal and optimal 5' exon and lariat intermediates indiscriminately. Finally, we demonstrate a requirement for Prp43p in repressing splicing at a cryptic splice site. We propose a model for the fidelity of exon ligation in which the DEAH box ATPase Prp22p slows the flow of suboptimal intermediates through exon ligation and Prp43p generally promotes discard of intermediates, thereby establishing a pathway for turnover of stalled intermediates. Because Prp43p also promotes spliceosome disassembly after exon ligation, this work establishes a parallel between the discard of suboptimal intermediates and the dissociation of a genuine excised intron product.
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37
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Millevoi S, Vagner S. Molecular mechanisms of eukaryotic pre-mRNA 3' end processing regulation. Nucleic Acids Res 2009; 38:2757-74. [PMID: 20044349 PMCID: PMC2874999 DOI: 10.1093/nar/gkp1176] [Citation(s) in RCA: 303] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Messenger RNA (mRNA) 3′ end formation is a nuclear process through which all eukaryotic primary transcripts are endonucleolytically cleaved and most of them acquire a poly(A) tail. This process, which consists in the recognition of defined poly(A) signals of the pre-mRNAs by a large cleavage/polyadenylation machinery, plays a critical role in gene expression. Indeed, the poly(A) tail of a mature mRNA is essential for its functions, including stability, translocation to the cytoplasm and translation. In addition, this process serves as a bridge in the network connecting the different transcription, capping, splicing and export machineries. It also participates in the quantitative and qualitative regulation of gene expression in a variety of biological processes through the selection of single or alternative poly(A) signals in transcription units. A large number of protein factors associates with this machinery to regulate the efficiency and specificity of this process and to mediate its interaction with other nuclear events. Here, we review the eukaryotic 3′ end processing machineries as well as the comprehensive set of regulatory factors and discuss the different molecular mechanisms of 3′ end processing regulation by proposing several overlapping models of regulation.
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Affiliation(s)
- Stefania Millevoi
- Institut National de la Santé et de la Recherche Médicale U563, Toulouse, F-31000, France.
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38
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Yang XC, Burch BD, Yan Y, Marzluff WF, Dominski Z. FLASH, a proapoptotic protein involved in activation of caspase-8, is essential for 3' end processing of histone pre-mRNAs. Mol Cell 2009; 36:267-78. [PMID: 19854135 DOI: 10.1016/j.molcel.2009.08.016] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 07/27/2009] [Accepted: 08/14/2009] [Indexed: 12/24/2022]
Abstract
3' end processing of histone pre-mRNA requires U7 snRNP, which binds downstream of the cleavage site and recruits the endonuclease CPSF-73. U7 snRNP contains a unique Sm ring in which the canonical SmD2 protein is replaced by Lsm11. We used the yeast two-hybrid system to identify binding partners of Lsm11 and selected the proapoptotic protein FLASH. Human FLASH interacts with Lsm11 in vitro and stimulates 3' end processing of histone pre-mRNA in mammalian nuclear extracts. We also identified the FLASH ortholog in Drosophila and demonstrate that it interacts with Lsm11 in vitro and in vivo. Drosophila FLASH localizes to histone locus bodies, and its depletion from fly cells inhibits U7-dependent processing, resulting in polyadenylation of histone mRNAs. These results demonstrate that FLASH is an essential factor required for 3' end maturation of histone mRNAs in both vertebrates and invertebrates and suggest a potential link between this process and apoptosis.
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Affiliation(s)
- Xiao-Cui Yang
- Department of Biochemistry and Biophysics and Program in Molecular Biology and Biotechnology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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39
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Cheng PC, Chang HK, Chen SH. Quantitative nanoproteomics for protein complexes (QNanoPX) related to estrogen transcriptional action. Mol Cell Proteomics 2009; 9:209-24. [PMID: 19805454 DOI: 10.1074/mcp.m900183-mcp200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We developed an integrated proteomics approach using a chemically functionalized gold nanoparticle (AuNP) as a novel probe for affinity purification to analyze a large protein complex in vivo. We then applied this approach to globally map the transcriptional activation complex of the estrogen response element (ERE). This approach was designated as quantitative nanoproteomics for protein complexes (QNanoPX). In this approach, the positive AuNP-ERE probes were functionalized with polyethylene glycol (PEG), and the consensus sequence of ERE and negative AuNP-PEG probes were functionalized with PEG without the ERE via a thiolated self-assembly monolayer technique. The AuNP-ERE probe had substantially low nonspecific binding and high solubility, which resulted in a 20-fold enrichment of the factor compared with gel beads. In addition, the surface-only binding allows the probe to capture a large protein complex without any restrictions due to pore size. The affinity purification method was combined with MS-based quantitative proteomics and statistical methods to reveal the components of the ERE complex in MCF-7 cells and to identify those components within the complex that were altered by the presence of 17beta-estradiol (E2). Results indicated that a majority of proteins pulled down by the positive probe exhibited significant binding, and approximately one-half of the proteins, including estrogen receptor alpha (ERalpha), were slightly but significantly affected by a 24-h treatment with E2. Based on a combination of bioinformatics and pathway analysis, most of the affected proteins, however, appeared to be related to the transcriptional regulation of not only ERalpha but also c-Myc. Further confirmation indicated that E2 enhanced the ERE binding of c-Myc by 14-fold, indicating that c-Myc may play a major role, along with ERalpha, in E2-mediated transcription. Taken together, our results demonstrated a successful QNanoPX approach toward new pathway discovery and further revealed the importance of cross-interactions among transcription factors.
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Affiliation(s)
- Pai-Chiao Cheng
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan
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40
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A core complex of CPSF73, CPSF100, and Symplekin may form two different cleavage factors for processing of poly(A) and histone mRNAs. Mol Cell 2009; 34:322-32. [PMID: 19450530 DOI: 10.1016/j.molcel.2009.04.024] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 04/14/2009] [Accepted: 04/24/2009] [Indexed: 11/23/2022]
Abstract
Metazoan histone mRNAs are unique: their pre-mRNAs contain no introns, and the mRNAs are not polyadenylated, ending instead in a conserved stem-loop structure. In Drosophila, canonical poly(A) signals are located downstream of the normal cleavage site of each histone gene and are utilized when histone 3' end formation is inhibited. Here we define a subcomplex of poly(A) factors that are required for histone pre-mRNA processing. We demonstrate that Symplekin, CPSF73, and CPSF100 are present in a stable complex and interact with histone-specific processing factors. We use chromatin immunoprecipitation to show that Symplekin and CPSF73, but not CstF50, cotranscriptionally associate with histone genes. Depletion of SLBP recruits CstF50 to histone genes. Knockdown of CPSF160 or CstF64 downregulates Symplekin but does not affect histone pre-mRNA processing or association of Symplekin with the histone locus. These results suggest that a common core cleavage factor is required for processing of histone and polyadenylated pre-mRNAs.
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41
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Xu B, Huang Y. Histone H2a mRNA interacts with Lin28 and contains a Lin28-dependent posttranscriptional regulatory element. Nucleic Acids Res 2009; 37:4256-63. [PMID: 19443445 PMCID: PMC2715237 DOI: 10.1093/nar/gkp372] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Lin28 has been shown to block the processing of let-7 microRNAs implicated in the regulation of cell growth and differentiation. Here, we show that Lin28 also specifically associates with ribonucleoprotein particles containing the replication-dependent histone H2a mRNA in mouse embryonic stem cells. We further show that the coding region of H2a mRNA harbors high affinity binding sequences for Lin28 and that these sequences stimulate the expression of reporter genes in a Lin28-dependent manner. We suggest that a key function of Lin28 in the maintenance of pluripotency is to promote the expression of the H2a gene (and perhaps also other replication-dependent histone genes) at the posttranscriptional level in order to coordinate histone production with the unique proliferative properties of embryonic stem cells.
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Affiliation(s)
- Bingsen Xu
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, 300 George Street, New Haven, CT 06511, USA and Reproductive Medicine Center, The First Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, 325000, P.R. China
| | - Yingqun Huang
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, 300 George Street, New Haven, CT 06511, USA and Reproductive Medicine Center, The First Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, 325000, P.R. China
- *To whom correspondence should be addressed. Tel: +1 203 737 2578; Fax: +1 203 785 7134;
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42
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Sullivan KD, Mullen TE, Marzluff WF, Wagner EJ. Knockdown of SLBP results in nuclear retention of histone mRNA. RNA (NEW YORK, N.Y.) 2009; 15:459-72. [PMID: 19155325 PMCID: PMC2657014 DOI: 10.1261/rna.1205409] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Accepted: 11/14/2008] [Indexed: 05/23/2023]
Abstract
Histone mRNAs are the only eukaryotic cellular mRNAs that are not polyadenylated. Synthesis of mature histone mRNA requires only a single processing reaction: an endonucleolytic cleavage between a conserved stem-loop and a purine-rich downstream element to form the 3' end. The stem-loop binding protein (SLBP) is required for processing, and following processing, histone mRNA is transported to the cytoplasm, where SLBP participates in translation of the histone mRNA and is also involved in regulation of histone mRNA degradation. Here we present an analysis of histone mRNA metabolism in cells with highly reduced levels of SLBP using RNA interference. Knocking down SLBP in U2OS cells results in a reduction in the rate of cell growth and an accumulation of cells in S-phase. Surprisingly, there is only a modest (twofold) decrease in histone mRNA levels. Much of histone mRNA in the SLBP knockdown cells is properly processed but is retained in the nucleus. The processed histone mRNA in SLBP knockdown cells is not rapidly degraded when DNA replication is inhibited. These results suggest a previously undescribed role for SLBP in histone mRNA export.
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Affiliation(s)
- Kelly D Sullivan
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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43
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Tanuma N, Kim SE, Beullens M, Tsubaki Y, Mitsuhashi S, Nomura M, Kawamura T, Isono K, Koseki H, Sato M, Bollen M, Kikuchi K, Shima H. Nuclear inhibitor of protein phosphatase-1 (NIPP1) directs protein phosphatase-1 (PP1) to dephosphorylate the U2 small nuclear ribonucleoprotein particle (snRNP) component, spliceosome-associated protein 155 (Sap155). J Biol Chem 2008; 283:35805-14. [PMID: 18842582 DOI: 10.1074/jbc.m805468200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pre-mRNA splicing entails reversible phosphorylation of spliceosomal proteins. Recent work has revealed essential roles for Ser/Thr phosphatases, such as protein phosphatase-1 (PP1), in splicing, but how these phosphatases are regulated is largely unknown. We show that nuclear inhibitor of PP1 (NIPP1), a major PP1 interactor in the vertebrate nucleus, recruits PP1 to Sap155 (spliceosome-associated protein 155), an essential component of U2 small nuclear ribonucleoprotein particles, and promotes Sap155 dephosphorylation. C-terminally truncated NIPP1 (NIPP1-DeltaC) formed a hyper-active holoenzyme with PP1, rendering PP1 minimally phosphorylated on an inhibitory site. Forced expression of NIPP1-WT and -DeltaC resulted in slight and severe decreases in Sap155 hyperphosphorylation, respectively, and the latter was accompanied with inhibition of splicing. PP1 overexpression produced similar effects, whereas small interfering RNA-mediated NIPP1 knockdown enhanced Sap155 hyperphosphorylation upon okadaic acid treatment. NIPP1 did not inhibit but rather stimulated Sap155 dephosphorylation by PP1 in vitro through facilitating Sap155/PP1 interaction. Further analysis revealed that NIPP1 specifically recognizes hyperphosphorylated Sap155 thorough its Forkhead-associated domain and dissociates from Sap155 after dephosphorylation by associated PP1. Thus NIPP1 works as a molecular sensor for PP1 to recognize phosphorylated Sap155.
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Affiliation(s)
- Nobuhiro Tanuma
- Division of Cancer Chemotherapy, Miyagi Cancer Center Research Institute, Natori 981-1293, Japan.
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Morris GE. The Cajal body. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:2108-15. [PMID: 18755223 DOI: 10.1016/j.bbamcr.2008.07.016] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 07/21/2008] [Accepted: 07/23/2008] [Indexed: 12/30/2022]
Abstract
The Cajal body, originally identified over 100 years ago as a nucleolar accessory body in neurons, has come to be identified with nucleoplasmic structures, often quite tiny, that contain coiled threads of the marker protein, coilin. The interaction of coilin with other proteins appears to increase the efficiency of several nuclear processes by concentrating their components in the Cajal body. The best-known of these processes is the modification and assembly of U snRNPs, some of which eventually form the RNA splicing machinery, or spliceosome. Over the last 10 years, research into the function of Cajal bodies has been greatly stimulated by the discovery that SMN, the protein deficient in the inherited neuromuscular disease, spinal muscular atrophy, is a Cajal body component and has an essential role in the assembly of spliceosomal U snRNPs in the cytoplasm and their delivery to the Cajal body in the nucleus.
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Affiliation(s)
- Glenn E Morris
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, OSWESTRY, SY10 7AG, UK.
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Friend K, Kolev NG, Shu MD, Steitz JA. Minor-class splicing occurs in the nucleus of the Xenopus oocyte. RNA (NEW YORK, N.Y.) 2008; 14:1459-62. [PMID: 18567814 PMCID: PMC2491479 DOI: 10.1261/rna.1119708] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A small fraction of premessenger RNA introns in certain eukaryotes is excised by the minor spliceosome, which contains low-abundance small nuclear ribonucleoproteins (snRNPs). Recently, it was suggested that minor-class snRNPs are localized to and function in the cytoplasm of vertebrate cells. To test whether U12-type splicing occurs in the cytoplasm of Xenopus oocytes, we performed microinjections of the well-characterized P120 minor-class splicing substrate into the nucleus or into the cytoplasm. Our results demonstrate that accurate splicing of this U12-dependent intron occurs exclusively in the nuclear compartment of the oocyte, where U12 and U6atac snRNPs are primarily localized. We further demonstrate that splicing of both a major-class and a minor-class intron is inhibited after nuclear envelope breakdown during meiosis.
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Nicholson P, Müller B. Post-transcriptional control of animal histone gene expression--not so different after all... MOLECULAR BIOSYSTEMS 2008; 4:721-5. [PMID: 18563245 DOI: 10.1039/b802133c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Histone proteins are essential components of eukaryotic chromosomes. The expression of histone genes is cell cycle controlled and coupled to DNA replication, to ensure the packaging of replicated DNA into chromatin. The post-transcriptional control of histone gene expression is a key element in this coupling to DNA replication. It involves mRNA 3' end formation by histone-specific nuclear RNA processing, which produces mRNAs lacking a poly(A) tail, translation and mRNA stability control. This requires several histone-specific trans-acting factors and was thought to be a special case. Here we review recent observations that now reveal that many of the factors involved are shared with processing, translation and degradation of poly(A) mRNA.
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Affiliation(s)
- Pamela Nicholson
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
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Abstract
Polyadenylated mRNAs and replication-dependent histone mRNAs, which are not polyadenylated, share factors involved in 3' end formation. Friend et al. (2007) now report that the U2 snRNP, required for pre-mRNA splicing, is also required for histone mRNA 3' end formation.
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