1
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Bentley DL. Multiple Forms and Functions of Premature Termination by RNA Polymerase II. J Mol Biol 2024:168743. [PMID: 39127140 DOI: 10.1016/j.jmb.2024.168743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 08/05/2024] [Accepted: 08/06/2024] [Indexed: 08/12/2024]
Abstract
Eukaryotic genomes are widely transcribed by RNA polymerase II (pol II) both within genes and in intergenic regions. POL II elongation complexes comprising the polymerase, the DNA template and nascent RNA transcript must be extremely processive in order to transcribe the longest genes which are over 1 megabase long and take many hours to traverse. Dedicated termination mechanisms are required to disrupt these highly stable complexes. Transcription termination occurs not only at the 3' ends of genes once a full length transcript has been made, but also within genes and in promiscuously transcribed intergenic regions. Termination at these latter positions is termed "premature" because it is not triggered in response to a specific signal that marks the 3' end of a gene, like a polyA site. One purpose of premature termination is to remove polymerases from intergenic regions where they are "not wanted" because they may interfere with transcription of overlapping genes or the progress of replication forks. Premature termination has recently been appreciated to occur at surprisingly high rates within genes where it is speculated to serve regulatory or quality control functions. In this review I summarize current understanding of the different mechanisms of premature termination and its potential functions.
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Affiliation(s)
- David L Bentley
- Dept. Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA.
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2
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Mérida-Cerro JA, Maraver-Cárdenas P, Rondón AG, Aguilera A. Rat1 promotes premature transcription termination at R-loops. Nucleic Acids Res 2024; 52:3623-3635. [PMID: 38281203 DOI: 10.1093/nar/gkae033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 01/04/2024] [Accepted: 01/10/2024] [Indexed: 01/30/2024] Open
Abstract
Certain DNA sequences can adopt a non-B form in the genome that interfere with DNA-templated processes, including transcription. Among the sequences that are intrinsically difficult to transcribe are those that tend to form R-loops, three-stranded nucleic acid structures formed by a DNA-RNA hybrid and the displaced ssDNA. Here we compared the transcription of an endogenous gene with and without an R-loop-forming sequence inserted. We show that, in agreement with previous in vivo and in vitro analyses, transcription elongation is delayed by R-loops in yeast. Importantly, we demonstrate that the Rat1 transcription terminator factor facilitates transcription throughout such structures by inducing premature termination of arrested RNAPIIs. We propose that RNase H degrades the RNA moiety of the hybrid, providing an entry site for Rat1. Thus, we have uncovered an unanticipated function of Rat1 as a transcription restoring factor opening up the possibility that it may also promote transcription through other genomic DNA structures intrinsically difficult to transcribe. If R-loop-mediated transcriptional stress is not relieved by Rat1, it will cause genomic instability, probably through the increase of transcription-replication conflicts, a deleterious situation that could lead to cancer.
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Affiliation(s)
- José Antonio Mérida-Cerro
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla, CSIC, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Pablo Maraver-Cárdenas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla, CSIC, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Ana G Rondón
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla, CSIC, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla, CSIC, 41092 Seville, Spain; Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
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3
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Zeng Y, Zhang HW, Wu XX, Zhang Y. Structural basis of exoribonuclease-mediated mRNA transcription termination. Nature 2024; 628:887-893. [PMID: 38538796 DOI: 10.1038/s41586-024-07240-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 02/26/2024] [Indexed: 04/06/2024]
Abstract
Efficient termination is required for robust gene transcription. Eukaryotic organisms use a conserved exoribonuclease-mediated mechanism to terminate the mRNA transcription by RNA polymerase II (Pol II)1-5. Here we report two cryogenic electron microscopy structures of Saccharomyces cerevisiae Pol II pre-termination transcription complexes bound to the 5'-to-3' exoribonuclease Rat1 and its partner Rai1. Our structures show that Rat1 displaces the elongation factor Spt5 to dock at the Pol II stalk domain. Rat1 shields the RNA exit channel of Pol II, guides the nascent RNA towards its active centre and stacks three nucleotides at the 5' terminus of the nascent RNA. The structures further show that Rat1 rotates towards Pol II as it shortens RNA. Our results provide the structural mechanism for the Rat1-mediated termination of mRNA transcription by Pol II in yeast and the exoribonuclease-mediated termination of mRNA transcription in other eukaryotes.
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MESH Headings
- Cryoelectron Microscopy
- Exoribonucleases/chemistry
- Exoribonucleases/metabolism
- Exoribonucleases/ultrastructure
- Models, Molecular
- Protein Binding
- RNA Polymerase II/chemistry
- RNA Polymerase II/metabolism
- RNA Polymerase II/ultrastructure
- RNA, Messenger/biosynthesis
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- RNA, Messenger/ultrastructure
- RNA-Binding Proteins/chemistry
- RNA-Binding Proteins/metabolism
- RNA-Binding Proteins/ultrastructure
- Saccharomyces cerevisiae/chemistry
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Saccharomyces cerevisiae/ultrastructure
- Saccharomyces cerevisiae Proteins/chemistry
- Saccharomyces cerevisiae Proteins/metabolism
- Saccharomyces cerevisiae Proteins/ultrastructure
- Transcription Termination, Genetic
- Transcriptional Elongation Factors/chemistry
- Transcriptional Elongation Factors/metabolism
- Transcriptional Elongation Factors/ultrastructure
- Chromosomal Proteins, Non-Histone/chemistry
- Chromosomal Proteins, Non-Histone/metabolism
- Chromosomal Proteins, Non-Histone/ultrastructure
- Protein Domains
- RNA, Fungal/biosynthesis
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- RNA, Fungal/ultrastructure
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Affiliation(s)
- Yuan Zeng
- Key Laboratory of Synthetic Biology, National Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hong-Wei Zhang
- Key Laboratory of Synthetic Biology, National Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiao-Xian Wu
- Key Laboratory of Synthetic Biology, National Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, National Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
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4
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Zanin O, Eastham M, Winczura K, Ashe M, Martinez-Nunez RT, Hebenstreit D, Grzechnik P. Ceg1 depletion reveals mechanisms governing degradation of non-capped RNAs in Saccharomyces cerevisiae. Commun Biol 2023; 6:1112. [PMID: 37919390 PMCID: PMC10622555 DOI: 10.1038/s42003-023-05495-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 10/20/2023] [Indexed: 11/04/2023] Open
Abstract
Most functional eukaryotic mRNAs contain a 5' 7-methylguanosine (m7G) cap. Although capping is essential for many biological processes including mRNA processing, export and translation, the fate of uncapped transcripts has not been studied extensively. Here, we employed fast nuclear depletion of the capping enzymes in Saccharomyces cerevisiae to uncover the turnover of the transcripts that failed to be capped. We show that although the degradation of cap-deficient mRNA is dominant, the levels of hundreds of non-capped mRNAs increase upon depletion of the capping enzymes. Overall, the abundance of non-capped mRNAs is inversely correlated to the expression levels, altogether resembling the effects observed in cells lacking the cytoplasmic 5'-3' exonuclease Xrn1 and indicating differential degradation fates of non-capped mRNAs. The inactivation of the nuclear 5'-3' exonuclease Rat1 does not rescue the non-capped mRNA levels indicating that Rat1 is not involved in their degradation and consequently, the lack of the capping does not affect the distribution of RNA Polymerase II on the chromatin. Our data indicate that the cap presence is essential to initiate the Xrn1-dependent degradation of mRNAs underpinning the role of 5' cap in the Xrn1-dependent buffering of the cellular mRNA levels.
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Affiliation(s)
- Onofrio Zanin
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- School of Immunology & Microbial Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - Matthew Eastham
- Division of Molecular and Cellular Function, School of Biological Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Kinga Winczura
- Division of Molecular and Cellular Function, School of Biological Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Mark Ashe
- Division of Molecular and Cellular Function, School of Biological Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Rocio T Martinez-Nunez
- School of Immunology & Microbial Sciences, King's College London, Guy's Campus, London, SE1 9RT, UK
| | | | - Pawel Grzechnik
- Division of Molecular and Cellular Function, School of Biological Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
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5
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Collin A, González-Jiménez A, González-Jiménez MDC, Alfonso MJ, Calvo O. The Role of S. cerevisiae Sub1/PC4 in Transcription Elongation Depends on the C-Terminal Region and Is Independent of the ssDNA Binding Domain. Cells 2022; 11:cells11203320. [PMID: 36291192 PMCID: PMC9600219 DOI: 10.3390/cells11203320] [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: 09/07/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/30/2022] Open
Abstract
Saccharomyces cerevisiae Sub1 (ScSub1) has been defined as a transcriptional stimulatory protein due to its homology to the ssDNA binding domain (ssDBD) of human PC4 (hPC4). Recently, PC4/Sub1 orthologues have been elucidated in eukaryotes, prokaryotes, and bacteriophages with functions related to DNA metabolism. Additionally, ScSub1 contains a unique carboxyl–terminal region (CT) of unknown function up to date. Specifically, it has been shown that Sub1 is required for transcription activation, as well as other processes, throughout the transcription cycle. Despite the progress that has been made in understanding the mechanism underlying Sub1′s functions, some questions remain unanswered. As a case in point: whether Sub1’s roles in initiation and elongation are differentially predicated on distinct regions of the protein or how Sub1′s functions are regulated. Here, we uncover some residues that are key for DNA–ScSub1 interaction in vivo, localized in the ssDBD, and required for Sub1 recruitment to promoters. Furthermore, using an array of genetic and molecular techniques, we demonstrate that the CT region is required for transcription elongation by RNA polymerase II (RNAPII). Altogether, our data indicate that Sub1 plays a dual role during transcription—in initiation through the ssDBD and in elongation through the CT region.
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Affiliation(s)
- Alejandro Collin
- Cátedra de Bioquímica y Biología Molecular, Facultad de Ciencias Médicas-INICSA, CONICET-Universidad Nacional de Córdoba, Haya de la Torre s/n, Pabellón Argentina, 2º piso. Ciudad Universitaria, Cordoba CP5000, Argentina
| | - Araceli González-Jiménez
- Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, C/ Zacarías González, nº2, 37007 Salamanca, Spain
| | | | - Manuel J. Alfonso
- Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, C/ Zacarías González, nº2, 37007 Salamanca, Spain
| | - Olga Calvo
- Instituto de Biología Funcional y Genómica (IBFG), CSIC-USAL, C/ Zacarías González, nº2, 37007 Salamanca, Spain
- Correspondence:
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6
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Cortazar MA, Erickson B, Fong N, Pradhan SJ, Ntini E, Bentley DL. Xrn2 substrate mapping identifies torpedo loading sites and extensive premature termination of RNA pol II transcription. Genes Dev 2022; 36:1062-1078. [PMID: 36396340 PMCID: PMC9744234 DOI: 10.1101/gad.350004.122] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/31/2022] [Indexed: 11/19/2022]
Abstract
The exonuclease torpedo Xrn2 loads onto nascent RNA 5'-PO4 ends and chases down pol II to promote termination downstream from polyA sites. We report that Xrn2 is recruited to preinitiation complexes and "travels" to 3' ends of genes. Mapping of 5'-PO4 ends in nascent RNA identified Xrn2 loading sites stabilized by an active site mutant, Xrn2(D235A). Xrn2 loading sites are approximately two to 20 bases downstream from where CPSF73 cleaves at polyA sites and histone 3' ends. We propose that processing of all mRNA 3' ends comprises cleavage and limited 5'-3' trimming by CPSF73, followed by handoff to Xrn2. A similar handoff occurs at tRNA 3' ends, where cotranscriptional RNase Z cleavage generates novel Xrn2 substrates. Exonuclease-dead Xrn2 increased transcription in 3' flanking regions by inhibiting polyA site-dependent termination. Surprisingly, the mutant Xrn2 also rescued transcription in promoter-proximal regions to the same extent as in 3' flanking regions. eNET-seq revealed Xrn2-mediated degradation of sense and antisense nascent RNA within a few bases of the TSS, where 5'-PO4 ends may be generated by decapping or endonucleolytic cleavage. These results suggest that a major fraction of pol II complexes terminates prematurely close to the start site under normal conditions by an Xrn2-mediated torpedo mechanism.
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Affiliation(s)
- Michael A. Cortazar
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Benjamin Erickson
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Nova Fong
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Sarala J. Pradhan
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Evgenia Ntini
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology–Hellas (FORTH), Heraklion GR-70013, Greece
| | - David L. Bentley
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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7
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Zardoni L, Nardini E, Brambati A, Lucca C, Choudhary R, Loperfido F, Sabbioneda S, Liberi G. Elongating RNA polymerase II and RNA:DNA hybrids hinder fork progression and gene expression at sites of head-on replication-transcription collisions. Nucleic Acids Res 2021; 49:12769-12784. [PMID: 34878142 PMCID: PMC8682787 DOI: 10.1093/nar/gkab1146] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 10/26/2021] [Accepted: 11/02/2021] [Indexed: 11/20/2022] Open
Abstract
Uncoordinated clashes between replication forks and transcription cause replication stress and genome instability, which are hallmarks of cancer and neurodegeneration. Here, we investigate the outcomes of head-on replication-transcription collisions, using as a model system budding yeast mutants for the helicase Sen1, the ortholog of human Senataxin. We found that RNA Polymerase II accumulates together with RNA:DNA hybrids at sites of head-on collisions. The replication fork and RNA Polymerase II are both arrested during the clash, leading to DNA damage and, in the long run, the inhibition of gene expression. The inactivation of RNA Polymerase II elongation factors, such as the HMG-like protein Spt2 and the DISF and PAF complexes, but not alterations in chromatin structure, allows replication fork progression through transcribed regions. Attenuation of RNA Polymerase II elongation rescues RNA:DNA hybrid accumulation and DNA damage sensitivity caused by the absence of Sen1, but not of RNase H proteins, suggesting that such enzymes counteract toxic RNA:DNA hybrids at different stages of the cell cycle with Sen1 mainly acting in replication. We suggest that the main obstacle to replication fork progression is the elongating RNA Polymerase II engaged in an R-loop, rather than RNA:DNA hybrids per se or hybrid-associated chromatin modifications.
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Affiliation(s)
- Luca Zardoni
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", CNR, 27100 Pavia, Italy.,Scuola Universitaria Superiore IUSS, 27100 Pavia, Italy
| | - Eleonora Nardini
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", CNR, 27100 Pavia, Italy
| | - Alessandra Brambati
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", CNR, 27100 Pavia, Italy
| | | | | | - Federica Loperfido
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", CNR, 27100 Pavia, Italy
| | - Simone Sabbioneda
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", CNR, 27100 Pavia, Italy
| | - Giordano Liberi
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza", CNR, 27100 Pavia, Italy.,IFOM Foundation, 20139 Milan, Italy
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8
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Dhoondia Z, Elewa H, Malik M, Arif Z, Pique-Regi R, Ansari A. A termination-independent role of Rat1 in cotranscriptional splicing. Nucleic Acids Res 2021; 49:5520-5536. [PMID: 33978753 PMCID: PMC8191773 DOI: 10.1093/nar/gkab339] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 04/12/2021] [Accepted: 04/19/2021] [Indexed: 01/18/2023] Open
Abstract
Rat1 is a 5′→3′ exoribonuclease in budding yeast. It is a highly conserved protein with homologs being present in fission yeast, flies, worms, mice and humans. Rat1 and its human homolog Xrn2 have been implicated in multiple nuclear processes. Here we report a novel role of Rat1 in mRNA splicing. We observed an increase in the level of unspliced transcripts in mutants of Rat1. Accumulation of unspliced transcripts was not due to the surveillance role of Rat1 in degrading unspliced mRNA, or an indirect effect of Rat1 function in termination of transcription or on the level of splicing factors in the cell, or due to an increased elongation rate in Rat1 mutants. ChIP-Seq analysis revealed Rat1 crosslinking to the introns of a subset of yeast genes. Mass spectrometry and coimmunoprecipitation revealed an interaction of Rat1 with the Clf1, Isy1, Yju2, Prp43 and Sub2 splicing factors. Furthermore, recruitment of splicing factors on the intron was compromised in the Rat1 mutant. Based on these findings we propose that Rat1 has a novel role in splicing of mRNA in budding yeast. Rat1, however, is not a general splicing factor as it crosslinks to only long introns with an average length of 400 nucleotides.
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Affiliation(s)
- Zuzer Dhoondia
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Hesham Elewa
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Marva Malik
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Zahidur Arif
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Roger Pique-Regi
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, 540 East Canfield, Detroit, MI 48201, USA
| | - Athar Ansari
- To whom correspondence should be addressed. Tel: +1 313 577 9251; Fax: +1 313 571 6891;
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9
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Interplay of mRNA capping and transcription machineries. Biosci Rep 2021; 40:221784. [PMID: 31904821 PMCID: PMC6981093 DOI: 10.1042/bsr20192825] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 01/02/2020] [Accepted: 01/06/2020] [Indexed: 12/31/2022] Open
Abstract
Early stages of transcription from eukaryotic promoters include two principal events: the capping of newly synthesized mRNA and the transition of RNA polymerase II from the preinitiation complex to the productive elongation state. The capping checkpoint model implies that these events are tightly coupled, which is necessary for ensuring the proper capping of newly synthesized mRNA. Recent findings also show that the capping machinery has a wider effect on transcription and the entire gene expression process. The molecular basis of these phenomena is discussed.
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10
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Yue L, Li J, Zhang B, Qi L, Li Z, Zhao F, Li L, Zheng X, Dong X. The conserved ribonuclease aCPSF1 triggers genome-wide transcription termination of Archaea via a 3'-end cleavage mode. Nucleic Acids Res 2020; 48:9589-9605. [PMID: 32857850 PMCID: PMC7515710 DOI: 10.1093/nar/gkaa702] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/07/2020] [Accepted: 08/12/2020] [Indexed: 01/16/2023] Open
Abstract
Transcription termination defines accurate transcript 3′-ends and ensures programmed transcriptomes, making it critical to life. However, transcription termination mechanisms remain largely unknown in Archaea. Here, we reported the physiological significance of the newly identified general transcription termination factor of Archaea, the ribonuclease aCPSF1, and elucidated its 3′-end cleavage triggered termination mechanism. The depletion of Mmp-aCPSF1 in Methanococcus maripaludis caused a genome-wide transcription termination defect and disordered transcriptome. Transcript-3′end-sequencing revealed that transcriptions primarily terminate downstream of a uridine-rich motif where Mmp-aCPSF1 performed an endoribonucleolytic cleavage, and the endoribonuclease activity was determined to be essential to the in vivo transcription termination. Co-immunoprecipitation and chromatin-immunoprecipitation detected interactions of Mmp-aCPSF1 with RNA polymerase and chromosome. Phylogenetic analysis revealed that the aCPSF1 orthologs are ubiquitously distributed among the archaeal phyla, and two aCPSF1 orthologs from Lokiarchaeota and Thaumarchaeota could replace Mmp-aCPSF1 to terminate transcription of M. maripaludis. Therefore, the aCPSF1 dependent termination mechanism could be widely employed in Archaea, including Lokiarchaeota belonging to Asgard Archaea, the postulated archaeal ancestor of Eukaryotes. Strikingly, aCPSF1-dependent archaeal transcription termination reported here exposes a similar 3′-cleavage mode as the eukaryotic RNA polymerase II termination, thus would shed lights on understanding the evolutionary linking between archaeal and eukaryotic termination machineries.
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Affiliation(s)
- Lei Yue
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, No. 19A Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Jie Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Bing Zhang
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Shijingshan District, Beijing 100049, China.,Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing 100101, China
| | - Lei Qi
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhihua Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, No. 19A Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Fangqing Zhao
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Shijingshan District, Beijing 100049, China.,Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing 100101, China
| | - Lingyan Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaowei Zheng
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiuzhu Dong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, No. 19A Yuquan Road, Shijingshan District, Beijing 100049, China
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11
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Yague-Sanz C, Vanrobaeys Y, Fernandez R, Duval M, Larochelle M, Beaudoin J, Berro J, Labbé S, Jacques PÉ, Bachand F. Nutrient-dependent control of RNA polymerase II elongation rate regulates specific gene expression programs by alternative polyadenylation. Genes Dev 2020; 34:883-897. [PMID: 32499400 PMCID: PMC7328516 DOI: 10.1101/gad.337212.120] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/06/2020] [Indexed: 12/22/2022]
Abstract
In this study from Yague-Sanz et al., the authors investigated the physiological relevance of variations in RNAPII elongation kinetics, and show in yeast that a RNAPII mutant that reduces the transcription elongation rate causes widespread changes in alternative polyadenylation (APA). Their findings indicate that RNAPII is a sensor of nucleotide availability and that genes important for nucleotide pool maintenance have adopted regulatory mechanisms responsive to reduced rates of transcription elongation. Transcription by RNA polymerase II (RNAPII) is a dynamic process with frequent variations in the elongation rate. However, the physiological relevance of variations in RNAPII elongation kinetics has remained unclear. Here we show in yeast that a RNAPII mutant that reduces the transcription elongation rate causes widespread changes in alternative polyadenylation (APA). We unveil two mechanisms by which APA affects gene expression in the slow mutant: 3′ UTR shortening and gene derepression by premature transcription termination of upstream interfering noncoding RNAs. Strikingly, the genes affected by these mechanisms are enriched for functions involved in phosphate uptake and purine synthesis, processes essential for maintenance of the intracellular nucleotide pool. As nucleotide concentration regulates transcription elongation, our findings argue that RNAPII is a sensor of nucleotide availability and that genes important for nucleotide pool maintenance have adopted regulatory mechanisms responsive to reduced rates of transcription elongation.
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Affiliation(s)
- Carlo Yague-Sanz
- Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Yann Vanrobaeys
- Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Ronan Fernandez
- Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, New Haven, Connecticut 06520, USA.,Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Maxime Duval
- Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Marc Larochelle
- Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Jude Beaudoin
- Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Julien Berro
- Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, New Haven, Connecticut 06520, USA.,Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Simon Labbé
- Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | | | - François Bachand
- Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
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12
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Burriss KH, Mosley AL. Methods review: Mass spectrometry analysis of RNAPII complexes. Methods 2019; 159-160:105-114. [PMID: 30902665 DOI: 10.1016/j.ymeth.2019.03.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/04/2019] [Accepted: 03/17/2019] [Indexed: 12/20/2022] Open
Abstract
RNA Polymerase II (RNAPII) is responsible for transcribing multiple RNA species throughout eukaryotes. A variety of protein-protein interactions occur throughout the transcription cycle for coordinated regulation of transcription initiation, elongation, and/or termination. Taking a proteomics approach to study RNAPII transcription thereby offers a comprehensive view of both RNAPII biology and the variety of proteins that regulate the process itself. This review will focus on how mass spectrometry (MS) methods have expanded understanding of RNAPII and its transcription-regulatory interaction partners. The application of affinity purification mass spectrometry has led to the discovery of a number of novel groups of proteins that regulate an array of RNAPII biology ranging from nuclear import to regulation of phosphorylation state. Additionally, a number of methods have been developed using mass spectrometry to measure protein subunit stoichiometry within and across protein complexes and to perform various types of architectural analysis using structural proteomics approaches. The key methods that we will focus on related to RNAPII mass spectrometry analyses include: affinity purification mass spectrometry, protein post-translational modification analysis, crosslinking mass spectrometry, and native mass spectrometry.
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Affiliation(s)
- Katlyn Hughes Burriss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46402, United States
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46402, United States; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46402, United States.
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13
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Peck SA, Hughes KD, Victorino JF, Mosley AL. Writing a wrong: Coupled RNA polymerase II transcription and RNA quality control. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1529. [PMID: 30848101 PMCID: PMC6570551 DOI: 10.1002/wrna.1529] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 12/27/2018] [Accepted: 02/07/2019] [Indexed: 12/20/2022]
Abstract
Processing and maturation of precursor RNA species is coupled to RNA polymerase II transcription. Co-transcriptional RNA processing helps to ensure efficient and proper capping, splicing, and 3' end processing of different RNA species to help ensure quality control of the transcriptome. Many improperly processed transcripts are not exported from the nucleus, are restricted to the site of transcription, and are in some cases degraded, which helps to limit any possibility of aberrant RNA causing harm to cellular health. These critical quality control pathways are regulated by the highly dynamic protein-protein interaction network at the site of transcription. Recent work has further revealed the extent to which the processes of transcription and RNA processing and quality control are integrated, and how critically their coupling relies upon the dynamic protein interactions that take place co-transcriptionally. This review focuses specifically on the intricate balance between 3' end processing and RNA decay during transcription termination. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Processing > 3' End Processing RNA Processing > Splicing Mechanisms RNA Processing > Capping and 5' End Modifications.
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Affiliation(s)
- Sarah A Peck
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Katlyn D Hughes
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Jose F Victorino
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
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14
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Larochelle M, Robert MA, Hébert JN, Liu X, Matteau D, Rodrigue S, Tian B, Jacques PÉ, Bachand F. Common mechanism of transcription termination at coding and noncoding RNA genes in fission yeast. Nat Commun 2018; 9:4364. [PMID: 30341288 PMCID: PMC6195540 DOI: 10.1038/s41467-018-06546-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 08/30/2018] [Indexed: 11/09/2022] Open
Abstract
Termination of RNA polymerase II (RNAPII) transcription is a fundamental step of gene expression that is critical for determining the borders between genes. In budding yeast, termination at protein-coding genes is initiated by the cleavage/polyadenylation machinery, whereas termination of most noncoding RNA (ncRNA) genes occurs via the Nrd1-Nab3-Sen1 (NNS) pathway. Here, we find that NNS-like transcription termination is not conserved in fission yeast. Rather, genome-wide analyses show global recruitment of mRNA 3' end processing factors at the end of ncRNA genes, including snoRNAs and snRNAs, and that this recruitment coincides with high levels of Ser2 and Tyr1 phosphorylation on the RNAPII C-terminal domain. We also find that termination of mRNA and ncRNA transcription requires the conserved Ysh1/CPSF-73 and Dhp1/XRN2 nucleases, supporting widespread cleavage-dependent transcription termination in fission yeast. Our findings thus reveal that a common mode of transcription termination can produce functionally and structurally distinct types of polyadenylated and non-polyadenylated RNAs.
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Affiliation(s)
- Marc Larochelle
- Département de Biochimie, Université de Sherbrooke, Sherbrooke, QC, J1E4K8, Canada
| | - Marc-Antoine Robert
- Départment de Biologie, Université de Sherbrooke, Sherbrooke, QC, J1K2R1, Canada
| | - Jean-Nicolas Hébert
- Département de Biochimie, Université de Sherbrooke, Sherbrooke, QC, J1E4K8, Canada
| | - Xiaochuan Liu
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School and Rutgers Cancer Institute of New Jersey, Newark, NJ, 07103, USA
| | - Dominick Matteau
- Départment de Biologie, Université de Sherbrooke, Sherbrooke, QC, J1K2R1, Canada
| | - Sébastien Rodrigue
- Départment de Biologie, Université de Sherbrooke, Sherbrooke, QC, J1K2R1, Canada
| | - Bin Tian
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School and Rutgers Cancer Institute of New Jersey, Newark, NJ, 07103, USA
| | - Pierre-Étienne Jacques
- Départment de Biologie, Université de Sherbrooke, Sherbrooke, QC, J1K2R1, Canada.
- Centre de Recherche du CHUS, Université de Sherbrooke, Sherbrooke, QC, J1H5N4, Canada.
| | - François Bachand
- Département de Biochimie, Université de Sherbrooke, Sherbrooke, QC, J1E4K8, Canada.
- Centre de Recherche du CHUS, Université de Sherbrooke, Sherbrooke, QC, J1H5N4, Canada.
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15
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16
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Grzechnik P, Szczepaniak SA, Dhir S, Pastucha A, Parslow H, Matuszek Z, Mischo HE, Kufel J, Proudfoot NJ. Nuclear fate of yeast snoRNA is determined by co-transcriptional Rnt1 cleavage. Nat Commun 2018; 9:1783. [PMID: 29725044 PMCID: PMC5934358 DOI: 10.1038/s41467-018-04094-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/04/2018] [Indexed: 01/30/2023] Open
Abstract
Small nucleolar RNA (snoRNA) are conserved and essential non-coding RNA that are transcribed by RNA Polymerase II (Pol II). Two snoRNA classes, formerly distinguished by their structure and ribonucleoprotein composition, act as guide RNA to target RNA such as ribosomal RNA, and thereby introduce specific modifications. We have studied the 5'end processing of individually transcribed snoRNA in S. cerevisiae to define their role in snoRNA biogenesis and functionality. Here we show that pre-snoRNA processing by the endonuclease Rnt1 occurs co-transcriptionally with removal of the m7G cap facilitating the formation of box C/D snoRNA. Failure of this process causes aberrant 3'end processing and mislocalization of snoRNA to the cytoplasm. Consequently, Rnt1-dependent 5'end processing of box C/D snoRNA is critical for snoRNA-dependent methylation of ribosomal RNA. Our results reveal that the 5'end processing of box C/D snoRNA defines their distinct pathway of maturation.
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Affiliation(s)
- Pawel Grzechnik
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK.
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Sylwia A Szczepaniak
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland
- College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, 02-089, Warsaw, Poland
| | - Somdutta Dhir
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Anna Pastucha
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland
| | - Hannah Parslow
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Zaneta Matuszek
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland
| | - Hannah E Mischo
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland.
| | - Nicholas J Proudfoot
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK.
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17
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Bresson S, Tollervey D. Surveillance-ready transcription: nuclear RNA decay as a default fate. Open Biol 2018; 8:170270. [PMID: 29563193 PMCID: PMC5881035 DOI: 10.1098/rsob.170270] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/23/2018] [Indexed: 12/21/2022] Open
Abstract
Eukaryotic cells synthesize enormous quantities of RNA from diverse classes, most of which are subject to extensive processing. These processes are inherently error-prone, and cells have evolved robust quality control mechanisms to selectively remove aberrant transcripts. These surveillance pathways monitor all aspects of nuclear RNA biogenesis, and in addition remove nonfunctional transcripts arising from spurious transcription and a host of non-protein-coding RNAs (ncRNAs). Surprisingly, this is largely accomplished with only a handful of RNA decay enzymes. It has, therefore, been unclear how these factors efficiently distinguish between functional RNAs and huge numbers of diverse transcripts that must be degraded. Here we describe how bona fide transcripts are specifically protected, particularly by 5' and 3' modifications. Conversely, a plethora of factors associated with the nascent transcripts all act to recruit the RNA quality control, surveillance and degradation machinery. We conclude that initiating RNAPII is 'surveillance ready', with degradation being a default fate for all transcripts that lack specific protective features. We further postulate that this promiscuity is a key feature that allowed the proliferation of vast numbers of ncRNAs in eukaryotes, including humans.
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Affiliation(s)
- Stefan Bresson
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - David Tollervey
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
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18
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Krzyszton M, Zakrzewska-Placzek M, Kwasnik A, Dojer N, Karlowski W, Kufel J. Defective XRN3-mediated transcription termination in Arabidopsis affects the expression of protein-coding genes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:1017-1031. [PMID: 29356198 DOI: 10.1111/tpj.13826] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/13/2017] [Accepted: 12/21/2017] [Indexed: 06/07/2023]
Abstract
Arabidopsis thaliana contains two nuclear XRN2/3 5'-3' exonucleases that are homologs of yeast and human Rat1/Xrn2 proteins involved in the processing and degradation of several classes of nuclear RNAs and in transcription termination of RNA polymerase II. Using strand-specific short read sequencing we show that knockdown of XRN3 leads to an altered expression of hundreds of genes and the accumulation of uncapped and polyadenylated read-through transcripts generated by inefficiently terminated Pol II. Our data support the notion that XRN3-mediated changes in the expression of a subset of genes are caused by upstream read-through transcription and these effects are enhanced by RNA-mRNA chimeras generated in xrn3 plants. In turn, read-through transcripts that are antisense to downstream genes may trigger production of siRNA. Our results highlight the importance of XRN3 exoribonuclease in Pol II transcription termination in plants and show that disturbance in this process may significantly alter gene expression.
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Affiliation(s)
- Michal Krzyszton
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland
| | - Monika Zakrzewska-Placzek
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland
| | - Aleksandra Kwasnik
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland
| | - Norbert Dojer
- Institute of Informatics, Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Banacha 2, 02-097, Warsaw, Poland
| | - Wojciech Karlowski
- Department of Computational Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614, Poznan, Poland
| | - Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland
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19
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Malik I, Qiu C, Snavely T, Kaplan CD. Wide-ranging and unexpected consequences of altered Pol II catalytic activity in vivo. Nucleic Acids Res 2017; 45:4431-4451. [PMID: 28119420 PMCID: PMC5416818 DOI: 10.1093/nar/gkx037] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 01/13/2017] [Indexed: 01/28/2023] Open
Abstract
Here we employ a set of RNA Polymerase II (Pol II) activity mutants to determine the consequences of increased or decreased Pol II catalysis on gene expression in Saccharomyces cerevisiae. We find that alteration of Pol II catalytic rate, either fast or slow, leads to decreased Pol II occupancy and apparent reduction in elongation rate in vivo. However, we also find that determination of elongation rate in vivo by chromatin immunoprecipitation can be confounded by the kinetics and conditions of transcriptional shutoff in the assay. We identify promoter and template-specific effects on severity of gene expression defects for both fast and slow Pol II mutants. We show that mRNA half-lives for a reporter gene are increased in both fast and slow Pol II mutant strains and the magnitude of half-life changes correlate both with mutants' growth and reporter expression defects. Finally, we tested a model that altered Pol II activity sensitizes cells to nucleotide depletion. In contrast to model predictions, mutated Pol II retains normal sensitivity to altered nucleotide levels. Our experiments establish a framework for understanding the diversity of transcription defects derived from altered Pol II activity mutants, essential for their use as probes of transcription mechanisms.
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Affiliation(s)
- Indranil Malik
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Chenxi Qiu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Thomas Snavely
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Craig D Kaplan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
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20
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Harlen KM, Churchman LS. Subgenic Pol II interactomes identify region-specific transcription elongation regulators. Mol Syst Biol 2017; 13:900. [PMID: 28043953 PMCID: PMC5293154 DOI: 10.15252/msb.20167279] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Transcription, RNA processing, and chromatin‐related factors all interact with RNA polymerase II (Pol II) to ensure proper timing and coordination of transcription and co‐transcriptional processes. Many transcription elongation regulators must function simultaneously to coordinate these processes, yet few strategies exist to explore the complement of factors regulating specific stages of transcription. To this end, we developed a strategy to purify Pol II elongation complexes from subgenic regions of a single gene, namely the 5′ and 3′ regions, using sequences in the nascent RNA. Applying this strategy to Saccharomyces cerevisiae, we determined the specific set of factors that interact with Pol II at precise stages during transcription. We identify many known region‐specific factors as well as determine unappreciated associations of regulatory factors during early and late stages of transcription. These data reveal a role for the transcription termination factor, Rai1, in regulating the early stages of transcription genome‐wide and support the role of Bye1 as a negative regulator of early elongation. We also demonstrate a role for the ubiquitin ligase, Bre1, in regulating Pol II dynamics during the latter stages of transcription. These data and our approach to analyze subgenic transcription elongation complexes will shed new light on the myriad factors that regulate the different stages of transcription and coordinate co‐transcriptional processes.
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Affiliation(s)
- Kevin M Harlen
- Department of Genetics, Harvard Medical School, Boston, MA, USA
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21
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Mosrin-Huaman C, Hervouet-Coste N, Rahmouni AR. Co-transcriptional degradation by the 5'-3' exonuclease Rat1p mediates quality control of HXK1 mRNP biogenesis in S. cerevisiae. RNA Biol 2016; 13:582-92. [PMID: 27124216 DOI: 10.1080/15476286.2016.1181255] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The co-transcriptional biogenesis of export-competent messenger ribonucleoprotein particles (mRNPs) in yeast is under the surveillance of quality control (QC) steps. Aberrant mRNPs resulting from inappropriate or inefficient processing and packaging reactions are detected by the QC system and retained in the nucleus with ensuing elimination of their mRNA component by a mechanism that requires the catalytic activity of Rrp6p, a 3'-5' exonuclease associated with the RNA exosome. In previous studies, we implemented a new experimental approach in which the production of aberrant mRNPs is massively increased upon perturbation of mRNP biogenesis by the RNA-dependent helicase/translocase activity of the bacterial Rho factor expressed in S. cerevisiae. The analyses of a subset of transcripts such as PMA1 led us to substantiate the essential role of Rrp6p in the nuclear mRNP QC and to reveal a functional coordination of the process by Nrd1p. Here, we extended those results by showing that, in contrast to PMA1, Rho-induced aberrant HXK1 mRNPs are targeted for destruction by an Nrd1p- and Rrp6p-independent alternative QC pathway that relies on the 5'-3' exonuclease activity of Rat1p. We show that the degradation of aberrant HXK1 mRNPs by Rat1p occurs co-transcriptionally following decapping by Dcp2p and leads to premature transcription termination. We discuss the possibility that this alternative QC pathway might be linked to the well-known specific features of the HXK1 gene transcription such as its localization at the nuclear periphery and gene loop formation.
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Affiliation(s)
| | | | - A Rachid Rahmouni
- a Centre de Biophysique Moléculaire , Rue Charles Sadron , Orléans , France
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22
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Quantitative regulation of FLC via coordinated transcriptional initiation and elongation. Proc Natl Acad Sci U S A 2015; 113:218-23. [PMID: 26699513 DOI: 10.1073/pnas.1518369112] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The basis of quantitative regulation of gene expression is still poorly understood. In Arabidopsis thaliana, quantitative variation in expression of FLOWERING LOCUS C (FLC) influences the timing of flowering. In ambient temperatures, FLC expression is quantitatively modulated by a chromatin silencing mechanism involving alternative polyadenylation of antisense transcripts. Investigation of this mechanism unexpectedly showed that RNA polymerase II (Pol II) occupancy changes at FLC did not reflect RNA fold changes. Mathematical modeling of these transcriptional dynamics predicted a tight coordination of transcriptional initiation and elongation. This prediction was validated by detailed measurements of total and chromatin-bound FLC intronic RNA, a methodology appropriate for analyzing elongation rate changes in a range of organisms. Transcription initiation was found to vary ∼ 25-fold with elongation rate varying ∼ 8- to 12-fold. Premature sense transcript termination contributed very little to expression differences. This quantitative variation in transcription was coincident with variation in H3K36me3 and H3K4me2 over the FLC gene body. We propose different chromatin states coordinately influence transcriptional initiation and elongation rates and that this coordination is likely to be a general feature of quantitative gene regulation in a chromatin context.
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23
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Conserved factor Dhp1/Rat1/Xrn2 triggers premature transcription termination and nucleates heterochromatin to promote gene silencing. Proc Natl Acad Sci U S A 2015; 112:15548-55. [PMID: 26631744 DOI: 10.1073/pnas.1522127112] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cotranscriptional RNA processing and surveillance factors mediate heterochromatin formation in diverse eukaryotes. In fission yeast, RNAi machinery and RNA elimination factors including the Mtl1-Red1 core and the exosome are involved in facultative heterochromatin assembly; however, the exact mechanisms remain unclear. Here we show that RNA elimination factors cooperate with the conserved exoribonuclease Dhp1/Rat1/Xrn2, which couples pre-mRNA 3'-end processing to transcription termination, to promote premature termination and facultative heterochromatin formation at meiotic genes. We also find that Dhp1 is critical for RNAi-mediated heterochromatin assembly at retroelements and regulated gene loci and facilitates the formation of constitutive heterochromatin at centromeric and mating-type loci. Remarkably, our results reveal that Dhp1 interacts with the Clr4/Suv39h methyltransferase complex and acts directly to nucleate heterochromatin. Our work uncovers a previously unidentified role for 3'-end processing and transcription termination machinery in gene silencing through premature termination and suggests that noncanonical transcription termination by Dhp1 and RNA elimination factors is linked to heterochromatin assembly. These findings have important implications for understanding silencing mechanisms targeting genes and repeat elements in higher eukaryotes.
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24
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Parenteau J, Lavoie M, Catala M, Malik-Ghulam M, Gagnon J, Abou Elela S. Preservation of Gene Duplication Increases the Regulatory Spectrum of Ribosomal Protein Genes and Enhances Growth under Stress. Cell Rep 2015; 13:2516-2526. [DOI: 10.1016/j.celrep.2015.11.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 09/15/2015] [Accepted: 11/09/2015] [Indexed: 02/08/2023] Open
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25
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Jimeno-González S, Ceballos-Chávez M, Reyes JC. A positioned +1 nucleosome enhances promoter-proximal pausing. Nucleic Acids Res 2015; 43:3068-78. [PMID: 25735750 PMCID: PMC4381062 DOI: 10.1093/nar/gkv149] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 02/13/2015] [Indexed: 02/07/2023] Open
Abstract
Chromatin distribution is not uniform along the human genome. In most genes there is a promoter-associated nucleosome free region (NFR) followed by an array of nucleosomes towards the gene body in which the first (+1) nucleosome is strongly positioned. The function of this characteristic chromatin distribution in transcription is not fully understood. Here we show in vivo that the +1 nucleosome plays a role in modulating RNA polymerase II (RNAPII) promoter-proximal pausing. When a +1 nucleosome is strongly positioned, elongating RNAPII has a tendency to stall at the promoter-proximal region, recruits more negative elongation factor (NELF) and produces less mRNA. The nucleosome-induced pause favors pre-mRNA quality control by promoting the addition of the cap to the nascent RNA. Moreover, the uncapped RNAs produced in the absence of a positioned nucleosome are degraded by the 5′-3′ exonuclease XRN2. Interestingly, reducing the levels of the chromatin remodeler ISWI factor SNF2H decreases +1 nucleosome positioning and increases RNAPII pause release. This work demonstrates a function for +1 nucleosome in regulation of transcription elongation, pre-mRNA processing and gene expression.
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Affiliation(s)
- Silvia Jimeno-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Consejo Superior de Investigaciones Científicas (CSIC), E-41012, Seville, Spain
| | - María Ceballos-Chávez
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Consejo Superior de Investigaciones Científicas (CSIC), E-41012, Seville, Spain
| | - José C Reyes
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Consejo Superior de Investigaciones Científicas (CSIC), E-41012, Seville, Spain
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26
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Abstract
All eukaryotic mRNAs are capped at their 5' end. Capping of mRNAs takes place co-transcriptionally and involves three steps. The intermediates of the capping process, as well as the uncapped 5' tri-phosphate RNA, are resistant to decapping and degradation by known factors, leading to the assumption that the capping process always proceeds to completion. This view was recently drastically changed. A novel family of enzymes, including the yeast proteins Rai1, Dxo1/Ydr370C, and the mammalian protein DXO/Dom3Z, has been identified. These enzymes catalyze the conversion of the improperly capped mRNAs to 5' mono-phosphate RNA, allowing them to be degraded by 5'-3' exoribonucleases. Several of these enzymes also possess 5'-3' exoribonuclease activities themselves, and can single-handedly clear the improperly capped mRNAs. Studying of these enzymes has led to the realization that mRNA capping does not always proceed to completion, and the identification of an mRNA capping quality control mechanism in eukaryotes. In this paper, we briefly review recent advances in this area.
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Affiliation(s)
- Li-ting Zhai
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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27
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Abstract
Eukaryotic mRNAs are extensively processed to generate functional transcripts, which are 5′ capped, spliced and 3′ polyadenylated. Accumulation of unprocessed (aberrant) mRNAs can be deleterious for the cell, hence processing fidelity is closely monitored by QC (quality control) mechanisms that identify erroneous transcripts and initiate their selective removal. Nucleases including Xrn2/Rat1 and the nuclear exosome have been shown to play an important role in the turnover of aberrant mRNAs. Recently, with the growing appreciation that mRNA processing occurs concomitantly with polII (RNA polymerase II) transcription, it has become evident that QC acts at the transcriptional level in addition to degrading aberrant RNAs. In the present review, we discuss mechanisms that allow cells to co-transcriptionally initiate the removal of RNAs as well as down-regulate transcription of transcripts where processing repeatedly fails.
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28
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Jimeno-González S, Schmid M, Malagon F, Haaning LL, Jensen TH. Rat1p maintains RNA polymerase II CTD phosphorylation balance. RNA (NEW YORK, N.Y.) 2014; 20:551-558. [PMID: 24501251 PMCID: PMC3964916 DOI: 10.1261/rna.041129.113] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 12/23/2013] [Indexed: 06/03/2023]
Abstract
In S. cerevisiae, the 5'-3' exonuclease Rat1p partakes in transcription termination. Although Rat1p-mediated RNA degradation has been suggested to play a role for this activity, the exact mechanisms by which Rat1p helps release RNA polymerase II (RNAPII) from the DNA template are poorly understood. Here we describe a function of Rat1p in regulating phosphorylation levels of the C-terminal domain (CTD) of the largest RNAPII subunit, Rpb1p, during transcription elongation. The rat1-1 mutant exhibits highly elevated levels of CTD phosphorylation as well as RNAPII distribution and transcription termination defects. These phenotypes are all rescued by overexpression of the CTD phosphatase Fcp1p, suggesting a functional relationship between the absence of Rat1p activity, elevated CTD phosphorylation, and transcription defects. We also demonstrate that rat1-1 cells display increased RNAPII transcription kinetics, a feature that may contribute to the cellular phenotypes of the mutant. Consistently, the rat1-1 allele is synthetic lethal with the rpb1-E1103G mutation, causing increased RNAPII speed, and is suppressed by the rpb2-10 mutation, causing slowed transcription. Thus, Rat1p plays more complex roles in controlling transcription than previously thought.
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Abstract
Different classes of RNA function in various cellular processes, and their biogenesis and turnover involve diverse RNases for processing and degradation. XRN2 is a 5'→3' exoribonuclease that is evolutionarily conserved in eukaryotes. It is predominantly localized in the nucleus and recognizes single-stranded RNA with a 5'-terminal monophosphate to degrade it processively to mononucleotides. In the present paper, we review functions of XRN2 and its cofactors in maturation, surveillance and activity control of several classes of RNA such as pre-mRNA (precursor mRNA), rRNA and snoRNA (small nucleolar RNA).
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A novel role for Cet1p mRNA 5'-triphosphatase in promoter proximal accumulation of RNA polymerase II in Saccharomyces cerevisiase. Genetics 2013; 196:161-76. [PMID: 24172134 DOI: 10.1534/genetics.113.158535] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Yeast mRNA 5'-triphosphatase, Cet1p, recognizes phosphorylated-RNA polymerase II as a component of capping machinery via Ceg1p for cotranscriptional formation of mRNA cap structure that recruits cap-binding complex (CBC) and protects mRNA from exonucleases. Here, we show that the accumulation of RNA polymerase II at the promoter proximal site of ADH1 is significantly enhanced in the absence of Cet1p. Similar results are also found at other genes. Cet1p is recruited to the 5' end of the coding sequence, and its absence impairs mRNA capping, and hence CBC recruitment. However, such an impaired recruitment of CBC does not enhance promoter proximal accumulation of RNA polymerase II. Thus, Cet1p specifically lowers the accumulation of RNA polymerase II at the promoter proximal site independently of mRNA cap structure or CBC. Further, we show that Cet1p's N-terminal domain, which is not involved in mRNA capping, decreases promoter proximal accumulation of RNA polymerase II. An accumulation of RNA polymerase II at the promoter proximal site in the absence of Cet1p's N-terminal domain is correlated with reduced transcription. Collectively, our results demonstrate a novel role of Cet1p in regulation of promoter proximal accumulation of RNA polymerase II independently of mRNA capping activity, and hence transcription in vivo.
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31
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External conditions inversely change the RNA polymerase II elongation rate and density in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:1248-55. [PMID: 24103494 DOI: 10.1016/j.bbagrm.2013.09.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/25/2013] [Accepted: 09/30/2013] [Indexed: 11/23/2022]
Abstract
Elongation speed is a key parameter in RNA polymerase II (RNA pol II) activity. It affects the transcription rate, while it is conditioned by the physicochemical environment it works in at the same time. For instance, it is well-known that temperature affects the biochemical reactions rates. Therefore in free-living organisms that are able to grow at various environmental temperatures, such as the yeast Saccharomyces cerevisiae, evolution should have not only shaped the structural and functional properties of this key enzyme, but should have also provided mechanisms and pathways to adapt its activity to the optimal performance required. We studied the changes in RNA pol II elongation speed caused by alternations in growth temperature in yeast to find that they strictly follow the Arrhenius equation, and that they also provoke an almost inverse proportional change in RNA pol II density within the optimal growth temperature range (26-37 °C). Moreover, we discovered that yeast cells control the transcription initiation rate by changing the total amount of available RNA pol II.
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Saguez C, Gonzales FA, Schmid M, Bøggild A, Latrick CM, Malagon F, Putnam A, Sanderson L, Jankowsky E, Brodersen DE, Jensen TH. Mutational analysis of the yeast RNA helicase Sub2p reveals conserved domains required for growth, mRNA export, and genomic stability. RNA (NEW YORK, N.Y.) 2013; 19:1363-1371. [PMID: 23962665 PMCID: PMC3854527 DOI: 10.1261/rna.040048.113] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 06/27/2013] [Indexed: 06/02/2023]
Abstract
Sub2p/UAP56 is a highly conserved DEAD-box RNA helicase involved in the packaging and nuclear export of mRNA/protein particles (mRNPs). In Saccharomyces cerevisiae, Sub2p is recruited to active chromatin by the pentameric THO complex and incorporated into the larger transcription-export (TREX) complex. Sub2p also plays a role in the maintenance of genome integrity as its inactivation causes severe transcription-dependent recombination of DNA. Despite the central role of Sub2p in early mRNP biology, little is known about its function. Here, we report the presence of an N-terminal motif (NTM) conserved specifically in the Sub2p branch of RNA helicases. Mutation of the NTM causes nuclear accumulation of poly(A)(+) RNA and impaired growth without affecting core helicase functions. Thus, the NTM functions as an autonomous unit. Moreover, two sub2 mutants, that are deficient in ATP binding, act in a trans-dominant negative fashion for growth and induce high recombination rates in vivo. Although wild-type Sub2p is prevented access to transcribed loci in such a background, this does not mechanistically explain the phenotype.
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Affiliation(s)
- Cyril Saguez
- Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Fernando A. Gonzales
- Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Manfred Schmid
- Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Andreas Bøggild
- Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Chrysa M. Latrick
- Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Francisco Malagon
- Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Andrea Putnam
- Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Lee Sanderson
- Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Eckhard Jankowsky
- Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Ditlev E. Brodersen
- Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Torben Heick Jensen
- Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
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Mikula M, Bomsztyk K, Goryca K, Chojnowski K, Ostrowski J. Heterogeneous nuclear ribonucleoprotein (HnRNP) K genome-wide binding survey reveals its role in regulating 3'-end RNA processing and transcription termination at the early growth response 1 (EGR1) gene through XRN2 exonuclease. J Biol Chem 2013; 288:24788-98. [PMID: 23857582 DOI: 10.1074/jbc.m113.496679] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The heterogeneous nuclear ribonucleoprotein K (hnRNPK) is a nucleic acid-binding protein that acts as a docking platform integrating signal transduction pathways to nucleic acid-related processes. Given that hnRNPK could be involved in other steps that compose gene expression the definition of its genome-wide occupancy is important to better understand its role in transcription and co-transcriptional processes. Here, we used chromatin immunoprecipitation followed by deep sequencing (ChIP-Seq) to analyze the genome-wide hnRNPK-DNA interaction in colon cancer cell line HCT116. 9.1/3.6 and 7.0/3.4 million tags were sequenced/mapped, then 1809 and 642 hnRNPK binding sites were detected in quiescent and 30-min serum-stimulated cells, respectively. The inspection of sequencing tracks revealed inducible hnRNPK recruitment along a number of immediate early gene loci, including EGR1 and ZFP36, with the highest densities present at the transcription termination sites. Strikingly, hnRNPK knockdown with siRNA resulted in increased pre-RNA levels transcribed downstream of the EGR1 polyadenylation (A) site suggesting altered 3'-end pre-RNA degradation. Further ChIP survey of hnRNPK knockdown uncovered decreased recruitment of the 5'-3' exonuclease XRN2 along EGR1 and downstream of the poly(A) signal without altering RNA polymerase II density at these sites. Immunoprecipitation of hnRNPK and XRN2 from intact and RNase A-treated nuclear extracts followed by shotgun mass spectrometry revealed the presence of hnRNPK and XRN2 in the same complexes along with other spliceosome-related proteins. Our data suggest that hnRNPK may play a role in recruitment of XRN2 to gene loci thus regulating coupling 3'-end pre-mRNA processing to transcription termination.
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Affiliation(s)
- Michal Mikula
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, 02-781 Warsaw, Poland.
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Pearson EL, Moore CL. Dismantling promoter-driven RNA polymerase II transcription complexes in vitro by the termination factor Rat1. J Biol Chem 2013; 288:19750-9. [PMID: 23689372 DOI: 10.1074/jbc.m112.434985] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proper RNA polymerase II (Pol II) transcription termination is essential to generate stable transcripts, to prevent interference at downstream loci, and to recycle Pol II back to the promoter (1-3). As such, termination is an intricately controlled process that is tightly regulated by a variety of different cis- and trans-acting factors (4, 5). Although many eukaryotic termination factors have been identified to date, the details of the precise molecular mechanisms governing termination remain to be elucidated. We devised an in vitro transcription system to study specific Pol II termination. We show for the first time that the exonucleolytic Rat1·Rai1 complex can elicit the release of stalled Pol II in vitro and can do so in the absence of other factors. We also find that Rtt103, which interacts with the Pol II C-terminal domain (CTD) and with Rat1, can rescue termination activity of an exonucleolytically deficient Rat1 mutant. In light of our findings, we posit a model whereby functional nucleolytic activity is not the feature of Rat1 that ultimately promotes termination. Degradation of the nascent transcript allows Rat1 to pursue Pol II in a guided fashion and arrive at the site of RNA exit from Pol II. Upon this arrival, however, it is perhaps the specific and direct contact between Rat1 and Pol II that transmits the signal to terminate transcription.
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Affiliation(s)
- Erika L Pearson
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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35
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Abstract
How do cells stop transcribing RNA Polymerase II to promote proper gene expression and prevent transcriptional havoc in the genome? In the case of Leishmania, a uniquely modified DNA base blocks RNA Polymerase II and suggests an interesting new model for transcription termination.
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Affiliation(s)
- Dane Z Hazelbaker
- Department of Biological Chemistry, Harvard Medical School, 240 Longwood Ave, Boston, MA 02115, USA
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36
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Picard-Jean F, Bougie I, Shuto S, Bisaillon M. The immunosuppressive agent mizoribine monophosphate is an inhibitor of the human RNA capping enzyme. PLoS One 2013; 8:e54621. [PMID: 23349942 PMCID: PMC3547949 DOI: 10.1371/journal.pone.0054621] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 12/13/2012] [Indexed: 11/18/2022] Open
Abstract
Mizoribine monophosphate (MZP) is a specific inhibitor of the cellular inosine-5′-monophosphate dehydrogenase (IMPDH), the enzyme catalyzing the rate-limiting step of de novo guanine nucleotide biosynthesis. MZP is a highly potent antagonistic inhibitor of IMPDH that blocks the proliferation of T and B lymphocytes that use the de novo pathway of guanine nucleotide synthesis almost exclusively. In the present study, we investigated the ability of MZP to directly inhibit the human RNA capping enzyme (HCE), a protein harboring both RNA 5′-triphosphatase and RNA guanylyltransferase activities. HCE is involved in the synthesis of the cap structure found at the 5′ end of eukaryotic mRNAs, which is critical for the splicing of the cap-proximal intron, the transport of mRNAs from the nucleus to the cytoplasm, and for both the stability and translation of mRNAs. Our biochemical studies provide the first insight that MZP can inhibit the formation of the RNA cap structure catalyzed by HCE. In the presence of MZP, the RNA 5′-triphosphatase activity appears to be relatively unaffected while the RNA guanylyltransferase activity is inhibited, indicating that the RNA guanylyltransferase activity is the main target of MZP inhibition. Kinetic studies reveal that MZP is a non-competitive inhibitor that likely targets an allosteric site on HCE. Mizoribine also impairs mRNA capping in living cells, which could account for the global mechanism of action of this therapeutic agent. Together, our study clearly demonstrates that mizoribine monophosphate inhibits the human RNA guanylyltransferase in vitro and impair mRNA capping in cellulo.
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Affiliation(s)
- Frédéric Picard-Jean
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Isabelle Bougie
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Satoshi Shuto
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Martin Bisaillon
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
- * E-mail:
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37
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Hazelbaker DZ, Marquardt S, Wlotzka W, Buratowski S. Kinetic competition between RNA Polymerase II and Sen1-dependent transcription termination. Mol Cell 2012. [PMID: 23177741 DOI: 10.1016/j.molcel.2012.10.014] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The essential helicase-like protein Sen1 mediates termination of RNA Polymerase II (Pol II) transcription at snoRNAs and other noncoding RNAs in yeast. A mutation in the Pol II subunit Rpb1 that increases the elongation rate increases read-through transcription at Sen1-mediated terminators. Termination and growth defects in sen1 mutant cells are partially suppressed by a slowly transcribing Pol II mutant and are exacerbated by a faster-transcribing Pol II mutant. Deletion of the nuclear exosome subunit Rrp6 allows visualization of noncoding RNA intermediates that are terminated but not yet processed. Sen1 mutants or faster-transcribing Pol II increase the average lengths of preprocessed snoRNA, CUT, and SUT transcripts, while slowed Pol II transcription produces shorter transcripts. These connections between transcription rate and Sen1 activity support a model whereby kinetic competition between elongating Pol II and Sen1 helicase establishes the temporal and spatial window for early Pol II termination.
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Affiliation(s)
- Dane Z Hazelbaker
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
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38
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A Tetrahymena Piwi bound to mature tRNA 3' fragments activates the exonuclease Xrn2 for RNA processing in the nucleus. Mol Cell 2012; 48:509-20. [PMID: 23084833 DOI: 10.1016/j.molcel.2012.09.010] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 07/26/2012] [Accepted: 09/07/2012] [Indexed: 11/21/2022]
Abstract
Emerging evidence suggests that Argonaute (Ago)/Piwi proteins have diverse functions in the nucleus and cytoplasm, but the molecular mechanisms employed in the nucleus remain poorly defined. The Tetrahymena thermophila Ago/Piwi protein Twi12 is essential for growth and functions in the nucleus. Twi12-bound small RNAs (sRNAs) are 3' tRNA fragments that contain modified bases and thus are attenuated for base pairing to targets. We show that Twi12 assembles an unexpected complex with the nuclear exonuclease Xrn2. Twi12 functions to stabilize and localize Xrn2, as well as to stimulate its exonuclease activity. Twi12 function depends on sRNA binding, which is required for its nuclear import. Depletion of Twi12 or Xrn2 induces a cellular ribosomal RNA processing defect known to result from limiting Xrn2 activity in other organisms. Our findings suggest a role for an Ago/Piwi protein and 3' tRNA fragments in nuclear RNA metabolism.
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39
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Mischo HE, Proudfoot NJ. Disengaging polymerase: terminating RNA polymerase II transcription in budding yeast. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:174-85. [PMID: 23085255 PMCID: PMC3793857 DOI: 10.1016/j.bbagrm.2012.10.003] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 10/01/2012] [Accepted: 10/05/2012] [Indexed: 11/29/2022]
Abstract
Termination of transcription by RNA polymerase II requires two distinct processes: The formation of a defined 3′ end of the transcribed RNA, as well as the disengagement of RNA polymerase from its DNA template. Both processes are intimately connected and equally pivotal in the process of functional messenger RNA production. However, research in recent years has elaborated how both processes can additionally be employed to control gene expression in qualitative and quantitative ways. This review embraces these new findings and attempts to paint a broader picture of how this final step in the transcription cycle is of critical importance to many aspects of gene regulation. This article is part of a Special Issue entitled: RNA polymerase II Transcript Elongation.
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Affiliation(s)
- Hannah E Mischo
- Cancer Research UK London Research Institute, Blanche Lane South Mimms, Herts, UK.
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40
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Abstract
Messenger RNAs transcribed by RNA polymerase II are modified at their 5'-end by the cotranscriptional addition of a 7-methylguanosine (m(7)G) cap. The cap is an important modulator of gene expression and the mechanism and components involved in its removal have been extensively studied. At least two decapping enzymes, Dcp2 and Nudt16, and an array of decapping regulatory proteins remove the m(7)G cap from an mRNA exposing the 5'-end to exonucleolytic decay. In contrast, relatively less is known about the decay of mRNAs that may be aberrantly capped. The recent demonstration that the Saccharomyces cerevisiae Rai1 protein selectively hydrolyzes aberrantly capped mRNAs provides new insights into the modulation of mRNA that lack a canonical m(7)G cap 5'-end. Whether an mRNA is uncapped or capped but missing the N7 methyl moiety, Rai1 hydrolyzes its 5'-end to generate an mRNA with a 5' monophosphate. Interestingly, Rai1 heterodimerizes with the Rat1 5'-3' exoribonuclease, which subsequently degrades the 5'-end monophosphorylated mRNA. Importantly, Rat1 stimulates the 5'-end hydrolysis activities of Rai1 to generate a 5'-end unprotected mRNA substrate for Rat1 and, in turn, Rai1 stimulates the activity of Rat1. The Rai1-Rat1 heterodimer functions as a molecular motor to detect and degrade mRNAs with aberrant caps and defines a novel quality control mechanism that ensures mRNA 5'-end integrity. The increase in aberrantly capped mRNA population following nutritional stress in S. cerevisiae demonstrates the presence of aberrantly capped mRNAs in cells and further reinforces the functional significance of the Rai1 in ensuring mRNA 5'-end integrity.
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Affiliation(s)
- Megerditch Kiledjian
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey, USA.
| | - Mi Zhou
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey, USA
| | - Xinfu Jiao
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey, USA
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41
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Schmid M, Jensen TH. Transcription-associated quality control of mRNP. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:158-68. [PMID: 22982197 DOI: 10.1016/j.bbagrm.2012.08.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 08/24/2012] [Accepted: 08/29/2012] [Indexed: 01/06/2023]
Abstract
Although a prime purpose of transcription is to produce RNA, a substantial amount of transcript is nevertheless turned over very early in its lifetime. During transcription RNAs are matured by nucleases from longer precursors and activities are also employed to exert quality control over the RNA synthesis process so as to discard, retain or transcriptionally silence unwanted molecules. In this review we discuss the somewhat paradoxical circumstance that the retention or turnover of RNA is often linked to its synthesis. This occurs via the association of chromatin, or the transcription elongation complex, with RNA degradation (co)factors. Although our main focus is on protein-coding genes, we also discuss mechanisms of transcription-connected turnover of non-protein-coding RNA from where important general principles are derived. This article is part of a Special Issue entitled: RNA polymerase II Transcript Elongation.
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Affiliation(s)
- Manfred Schmid
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C., Denmark
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42
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Davidson L, Kerr A, West S. Co-transcriptional degradation of aberrant pre-mRNA by Xrn2. EMBO J 2012; 31:2566-78. [PMID: 22522706 PMCID: PMC3365414 DOI: 10.1038/emboj.2012.101] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 03/27/2012] [Indexed: 11/09/2022] Open
Abstract
Eukaryotic protein-coding genes are transcribed as pre-mRNAs that are matured by capping, splicing and cleavage and polyadenylation. Although human pre-mRNAs can be long and complex, containing multiple introns and many alternative processing sites, they are usually processed co-transcriptionally. Mistakes during nuclear mRNA maturation could lead to potentially harmful transcripts that are important to eliminate. However, the processes of human pre-mRNA degradation are not well characterised in the human nucleus. We have studied how aberrantly processed pre-mRNAs are degraded and find a role for the 5'→3' exonuclease, Xrn2. Xrn2 associates with and co-transcriptionally degrades nascent β-globin transcripts, mutated to inhibit splicing or 3' end processing. Importantly, we provide evidence that many endogenous pre-mRNAs are also co-transcriptionally degraded by Xrn2 when their processing is inhibited by Spliceostatin A. Our data therefore establish a previously unknown function for Xrn2 and an important further aspect of pre-mRNA metabolism that occurs co-transcriptionally.
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Affiliation(s)
- Lee Davidson
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
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Brannan K, Kim H, Erickson B, Glover-Cutter K, Kim S, Fong N, Kiemele L, Hansen K, Davis R, Lykke-Andersen J, Bentley DL. mRNA decapping factors and the exonuclease Xrn2 function in widespread premature termination of RNA polymerase II transcription. Mol Cell 2012; 46:311-24. [PMID: 22483619 DOI: 10.1016/j.molcel.2012.03.006] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 12/27/2011] [Accepted: 03/08/2012] [Indexed: 02/07/2023]
Abstract
We report a function of human mRNA decapping factors in control of transcription by RNA polymerase II. Decapping proteins Edc3, Dcp1a, and Dcp2 and the termination factor TTF2 coimmunoprecipitate with Xrn2, the nuclear 5'-3' exonuclease "torpedo" that facilitates transcription termination at the 3' ends of genes. Dcp1a, Xrn2, and TTF2 localize near transcription start sites (TSSs) by ChIP-seq. At genes with 5' peaks of paused pol II, knockdown of decapping or termination factors Xrn2 and TTF2 shifted polymerase away from the TSS toward upstream and downstream distal positions. This redistribution of pol II is similar in magnitude to that caused by depletion of the elongation factor Spt5. We propose that coupled decapping of nascent transcripts and premature termination by the "torpedo" mechanism is a widespread mechanism that limits bidirectional pol II elongation. Regulated cotranscriptional decapping near promoter-proximal pause sites followed by premature termination could control productive pol II elongation.
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Affiliation(s)
- Kris Brannan
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
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Comparative dynamic transcriptome analysis (cDTA) reveals mutual feedback between mRNA synthesis and degradation. Genome Res 2012; 22:1350-9. [PMID: 22466169 PMCID: PMC3396375 DOI: 10.1101/gr.130161.111] [Citation(s) in RCA: 207] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
To monitor eukaryotic mRNA metabolism, we developed comparative dynamic transcriptome analysis (cDTA). cDTA provides absolute rates of mRNA synthesis and decay in Saccharomyces cerevisiae (Sc) cells with the use of Schizosaccharomyces pombe (Sp) as an internal standard. cDTA uses nonperturbing metabolic labeling that supersedes conventional methods for mRNA turnover analysis. cDTA reveals that Sc and Sp transcripts that encode orthologous proteins have similar synthesis rates, whereas decay rates are fivefold lower in Sp, resulting in similar mRNA concentrations despite the larger Sp cell volume. cDTA of Sc mutants reveals that a eukaryote can buffer mRNA levels. Impairing transcription with a point mutation in RNA polymerase (Pol) II causes decreased mRNA synthesis rates as expected, but also decreased decay rates. Impairing mRNA degradation by deleting deadenylase subunits of the Ccr4–Not complex causes decreased decay rates as expected, but also decreased synthesis rates. Extended kinetic modeling reveals mutual feedback between mRNA synthesis and degradation that may be achieved by a factor that inhibits synthesis and enhances degradation.
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45
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Schmid M, Jensen TH. Nuclear quality control of RNA polymerase II transcripts. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 1:474-85. [PMID: 21956943 DOI: 10.1002/wrna.24] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Eukaryotic RNA polymerase II produces an astounding diversity of transcripts. These may need to be 5(') capped, spliced, polyadenylated, and packaged with proteins before their export to the cytoplasm. Unscheduled accumulation of any RNA species can interfere with normal RNA metabolism and poses a serious hazard to cells. Yet, given the amount of primary transcripts and the complexity of the RNA maturation process, production of aberrant RNA species is unavoidable. Cells, therefore, employ nuclear RNA quality control mechanisms to rapidly degrade, actively retain, or transcriptionally silence unwanted RNAs. Pathways that monitor mRNA production are best understood and similar pathways are employed to destroy transcriptional noise. Finally, related mechanisms also contribute to gene regulation during normal growth.
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Affiliation(s)
- Manfred Schmid
- Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology, Aarhus University, C.F. Møllers Alle, Bldg. 130, 8000 Aarhus C., Denmark
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Mühlemann O, Jensen TH. mRNP quality control goes regulatory. Trends Genet 2012; 28:70-7. [DOI: 10.1016/j.tig.2011.11.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 11/04/2011] [Accepted: 11/08/2011] [Indexed: 01/19/2023]
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Bernstein J, Toth EA. Yeast nuclear RNA processing. World J Biol Chem 2012; 3:7-26. [PMID: 22312453 PMCID: PMC3272586 DOI: 10.4331/wjbc.v3.i1.7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Revised: 11/27/2011] [Accepted: 12/04/2011] [Indexed: 02/05/2023] Open
Abstract
Nuclear RNA processing requires dynamic and intricately regulated machinery composed of multiple enzymes and their cofactors. In this review, we summarize recent experiments using Saccharomyces cerevisiae as a model system that have yielded important insights regarding the conversion of pre-RNAs to functional RNAs, and the elimination of aberrant RNAs and unneeded intermediates from the nuclear RNA pool. Much progress has been made recently in describing the 3D structure of many elements of the nuclear degradation machinery and its cofactors. Similarly, the regulatory mechanisms that govern RNA processing are gradually coming into focus. Such advances invariably generate many new questions, which we highlight in this review.
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Affiliation(s)
- Jade Bernstein
- Jade Bernstein, Eric A Toth, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, United States
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Krzyszton M, Zakrzewska-Placzek M, Koper M, Kufel J. Rat1 and Xrn2: The Diverse Functions of the Nuclear Rat1/Xrn2 Exonuclease. EUKARYOTIC RNASES AND THEIR PARTNERS IN RNA DEGRADATION AND BIOGENESIS, PART A 2012; 31:131-63. [DOI: 10.1016/b978-0-12-404740-2.00007-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Egecioglu DE, Kawashima TR, Chanfreau GF. Quality control of MATa1 splicing and exon skipping by nuclear RNA degradation. Nucleic Acids Res 2011; 40:1787-96. [PMID: 22021379 PMCID: PMC3287188 DOI: 10.1093/nar/gkr864] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The MATa1 gene encodes a transcriptional repressor that is an important modulator of sex-specific gene expression in Saccharomyces cerevisiae. MATa1 contains two small introns, both of which need to be accurately excised for proper expression of a functional MATa1 product and to avoid production of aberrant forms of the repressor. Here, we show that unspliced and partially spliced forms of the MATa1 mRNA are degraded by the nuclear exonuclease Rat1p, the nuclear exosome and by the nuclear RNase III endonuclease Rnt1p to prevent undesired expression of non-functional a1 proteins. In addition, we show that mis-spliced forms of MATa1 in which the splicing machinery has skipped exon2 and generated exon1–exon3 products are degraded by the nuclear 5′–3′ exonuclease Rat1p and by the nuclear exosome. This function for Rat1p and the nuclear exosome in the degradation of exon-skipped products is also observed for three other genes that contain two introns (DYN2, SUS1, YOS1), identifying a novel nuclear quality control pathway for aberrantly spliced RNAs that have skipped exons.
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Affiliation(s)
- Defne E Egecioglu
- Department of Chemistry & Biochemistry and the Molecular Biology Institute, University of California, Los Angeles, CA 90095-1569, USA
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50
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Lavoie M, Ge D, Abou Elela S. Regulation of conditional gene expression by coupled transcription repression and RNA degradation. Nucleic Acids Res 2011; 40:871-83. [PMID: 21933814 PMCID: PMC3258148 DOI: 10.1093/nar/gkr759] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Gene expression is determined by a combination of transcriptional and post-transcriptional regulatory events that were thought to occur independently. This report demonstrates that the genes associated with the Snf3p–Rgt2p glucose-sensing pathway are regulated by interconnected transcription repression and RNA degradation. Deletion of the dsRNA-specific ribonuclease III Rnt1p increased the expression of Snf3p–Rgt2p-associated transcription factors in vivo and the recombinant enzyme degraded their messenger RNA in vitro. Surprisingly, Rnt1ps effect on gene expression in vivo was both RNA and promoter dependent, thus linking RNA degradation to transcription. Strikingly, deletion of RNT1-induced promoter-specific transcription of the glucose sensing genes even in the absence of RNA cleavage signals. Together, the results presented here support a model in which co-transcriptional RNA degradation increases the efficiency of gene repression, thereby allowing an effective cellular response to the continuous changes in nutrient concentrations.
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Affiliation(s)
- Mathieu Lavoie
- RNA Group, Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada, J1H 5N4
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