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Determinants of Replication-Fork Pausing at tRNA Genes in Saccharomyces cerevisiae. Genetics 2020; 214:825-838. [PMID: 32071194 DOI: 10.1534/genetics.120.303092] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 02/12/2020] [Indexed: 12/21/2022] Open
Abstract
Transfer RNA (tRNA) genes are widely studied sites of replication-fork pausing and genome instability in the budding yeast Saccharomyces cerevisiae tRNAs are extremely highly transcribed and serve as constitutive condensin binding sites. tRNA transcription by RNA polymerase III has previously been identified as stimulating replication-fork pausing at tRNA genes, but the nature of the block to replication has not been incontrovertibly demonstrated. Here, we describe a systematic, genome-wide analysis of the contributions of candidates to replication-fork progression at tDNAs in yeast: transcription factor binding, transcription, topoisomerase activity, condensin-mediated clustering, and Rad18-dependent DNA repair. We show that an asymmetric block to replication is maintained even when tRNA transcription is abolished by depletion of one or more subunits of RNA polymerase III. By contrast, analogous depletion of the essential transcription factor TFIIIB removes the obstacle to replication. Therefore, our data suggest that the RNA polymerase III transcription complex itself represents an asymmetric obstacle to replication even in the absence of RNA synthesis. We additionally demonstrate that replication-fork progression past tRNA genes is unaffected by the global depletion of condensin from the nucleus, and can be stimulated by the removal of topoisomerases or Rad18-dependent DNA repair pathways.
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Ciesla M, Skowronek E, Boguta M. Function of TFIIIC, RNA polymerase III initiation factor, in activation and repression of tRNA gene transcription. Nucleic Acids Res 2019; 46:9444-9455. [PMID: 30053100 PMCID: PMC6182151 DOI: 10.1093/nar/gky656] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/10/2018] [Indexed: 01/09/2023] Open
Abstract
Transcription of transfer RNA genes by RNA polymerase III (Pol III) is controlled by general factors, TFIIIB and TFIIIC, and a negative regulator, Maf1. Here we report the interplay between TFIIIC and Maf1 in controlling Pol III activity upon the physiological switch of yeast from fermentation to respiration. TFIIIC directly competes with Pol III for chromatin occupancy as demonstrated by inversely correlated tDNA binding. The association of TFIIIC with tDNA was stronger under unfavorable respiratory conditions and in the presence of Maf1. Induction of tDNA transcription by glucose-activated protein kinase A (PKA) was correlated with the down-regulation of TFIIIC occupancy on tDNA. The conditions that activate the PKA signaling pathway promoted the binding of TFIIIB subunits, Brf1 and Bdp1, with tDNA, but decreased their interaction with TFIIIC. Association of Brf1 and Bdp1 with TFIIIC was much stronger under repressive conditions, potentially restricting TFIIIB recruitment to tDNA and preventing Pol III recruitment. Altogether, we propose a model in which, depending on growth conditions, TFIIIC promotes activation or repression of tDNA transcription.
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Affiliation(s)
- Malgorzata Ciesla
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Ewa Skowronek
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Magdalena Boguta
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
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3
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Ramsay EP, Vannini A. Structural rearrangements of the RNA polymerase III machinery during tRNA transcription initiation. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2018; 1861:285-294. [PMID: 29155071 DOI: 10.1016/j.bbagrm.2017.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/07/2017] [Accepted: 11/11/2017] [Indexed: 01/03/2023]
Abstract
RNA polymerase III catalyses the synthesis of tRNAs in eukaryotic organisms. Through combined biochemical and structural characterisation, multiple auxiliary factors have been identified alongside RNA Polymerase III as critical in both facilitating and regulating transcription. Together, this machinery forms dynamic multi-protein complexes at tRNA genes which are required for polymerase recruitment, DNA opening and initiation and elongation of the tRNA transcripts. Central to the function of these complexes is their ability to undergo multiple conformational changes and rearrangements that regulate each step. Here, we discuss the available biochemical and structural data on the structural plasticity of multi-protein complexes involved in RNA Polymerase III transcriptional initiation and facilitated re-initiation during tRNA synthesis. Increasingly, structural information is becoming available for RNA polymerase III and its functional complexes, allowing for a deeper understanding of tRNA transcriptional initiation. This article is part of a Special Issue entitled: SI: Regulation of tRNA synthesis and modification in physiological conditions and disease edited by Dr. Boguta Magdalena.
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MESH Headings
- Animals
- Eukaryotic Cells/metabolism
- Humans
- Models, Genetic
- Multiprotein Complexes/metabolism
- Promoter Regions, Genetic/genetics
- Protein Subunits
- RNA Polymerase III/chemistry
- RNA Polymerase III/metabolism
- RNA, Transfer/biosynthesis
- RNA, Transfer/genetics
- RNA, Transfer, Amino Acid-Specific/biosynthesis
- RNA, Transfer, Amino Acid-Specific/genetics
- Transcription Elongation, Genetic
- Transcription Factors/genetics
- Transcription Initiation, Genetic
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4
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Graczyk D, Cieśla M, Boguta M. Regulation of tRNA synthesis by the general transcription factors of RNA polymerase III - TFIIIB and TFIIIC, and by the MAF1 protein. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:320-329. [DOI: 10.1016/j.bbagrm.2018.01.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 01/20/2018] [Accepted: 01/21/2018] [Indexed: 01/03/2023]
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5
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Leśniewska E, Boguta M. Novel layers of RNA polymerase III control affecting tRNA gene transcription in eukaryotes. Open Biol 2017; 7:rsob.170001. [PMID: 28228471 PMCID: PMC5356446 DOI: 10.1098/rsob.170001] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 01/31/2017] [Indexed: 12/20/2022] Open
Abstract
RNA polymerase III (Pol III) transcribes a limited set of short genes in eukaryotes producing abundant small RNAs, mostly tRNA. The originally defined yeast Pol III transcriptome appears to be expanding owing to the application of new methods. Also, several factors required for assembly and nuclear import of Pol III complex have been identified recently. Models of Pol III based on cryo-electron microscopy reconstructions of distinct Pol III conformations reveal unique features distinguishing Pol III from other polymerases. Novel concepts concerning Pol III functioning involve recruitment of general Pol III-specific transcription factors and distinctive mechanisms of transcription initiation, elongation and termination. Despite the short length of Pol III transcription units, mapping of transcriptionally active Pol III with nucleotide resolution has revealed strikingly uneven polymerase distribution along all genes. This may be related, at least in part, to the transcription factors bound at the internal promoter regions. Pol III uses also a specific negative regulator, Maf1, which binds to polymerase under stress conditions; however, a subset of Pol III genes is not controlled by Maf1. Among other RNA polymerases, Pol III machinery represents unique features related to a short transcript length and high transcription efficiency.
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Affiliation(s)
- Ewa Leśniewska
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Magdalena Boguta
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
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6
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Transcription by RNA polymerase III: insights into mechanism and regulation. Biochem Soc Trans 2017; 44:1367-1375. [PMID: 27911719 PMCID: PMC5095917 DOI: 10.1042/bst20160062] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 07/07/2016] [Accepted: 07/13/2016] [Indexed: 12/13/2022]
Abstract
The highly abundant, small stable RNAs that are synthesized by RNA polymerase III (RNAPIII) have key functional roles, particularly in the protein synthesis apparatus. Their expression is metabolically demanding, and is therefore coupled to changing demands for protein synthesis during cell growth and division. Here, we review the regulatory mechanisms that control the levels of RNAPIII transcripts and discuss their potential physiological relevance. Recent analyses have revealed differential regulation of tRNA expression at all steps on its biogenesis, with significant deregulation of mature tRNAs in cancer cells.
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7
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Yeganeh M, Praz V, Cousin P, Hernandez N. Transcriptional interference by RNA polymerase III affects expression of the Polr3e gene. Genes Dev 2017; 31:413-421. [PMID: 28289142 PMCID: PMC5358760 DOI: 10.1101/gad.293324.116] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 02/15/2017] [Indexed: 01/21/2023]
Abstract
A mammalian interspersed repeat (MIR) nested in antisense orientation within the first intron of the Polr3e gene, encoding an RNA polymerase (Pol) III subunit, is conserved in mammals and highly occupied by Pol III. Here, Yeganeh et al. show that the MIR affects Polr3e expression through transcriptional interference. Overlapping gene arrangements can potentially contribute to gene expression regulation. A mammalian interspersed repeat (MIR) nested in antisense orientation within the first intron of the Polr3e gene, encoding an RNA polymerase III (Pol III) subunit, is conserved in mammals and highly occupied by Pol III. Using a fluorescence assay, CRISPR/Cas9-mediated deletion of the MIR in mouse embryonic stem cells, and chromatin immunoprecipitation assays, we show that the MIR affects Polr3e expression through transcriptional interference. Our study reveals a mechanism by which a Pol II gene can be regulated at the transcription elongation level by transcription of an embedded antisense Pol III gene.
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Affiliation(s)
- Meghdad Yeganeh
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Viviane Praz
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland.,Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Pascal Cousin
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Nouria Hernandez
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
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8
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Gadaleta MC, Noguchi E. Regulation of DNA Replication through Natural Impediments in the Eukaryotic Genome. Genes (Basel) 2017; 8:genes8030098. [PMID: 28272375 PMCID: PMC5368702 DOI: 10.3390/genes8030098] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Accepted: 03/03/2017] [Indexed: 02/07/2023] Open
Abstract
All living organisms need to duplicate their genetic information while protecting it from unwanted mutations, which can lead to genetic disorders and cancer development. Inaccuracies during DNA replication are the major cause of genomic instability, as replication forks are prone to stalling and collapse, resulting in DNA damage. The presence of exogenous DNA damaging agents as well as endogenous difficult-to-replicate DNA regions containing DNA–protein complexes, repetitive DNA, secondary DNA structures, or transcribing RNA polymerases, increases the risk of genomic instability and thus threatens cell survival. Therefore, understanding the cellular mechanisms required to preserve the genetic information during S phase is of paramount importance. In this review, we will discuss our current understanding of how cells cope with these natural impediments in order to prevent DNA damage and genomic instability during DNA replication.
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Affiliation(s)
- Mariana C Gadaleta
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA.
| | - Eishi Noguchi
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA.
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9
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Arimbasseri AG, Rijal K, Maraia RJ. Comparative overview of RNA polymerase II and III transcription cycles, with focus on RNA polymerase III termination and reinitiation. Transcription 2015; 5:e27639. [PMID: 25764110 DOI: 10.4161/trns.27369] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In eukaryotes, RNA polymerase (RNAP) III transcribes hundreds of genes for tRNAs and 5S rRNA, among others, which share similar promoters and stable transcription initiation complexes (TIC), which support rapid RNAP III recycling. In contrast, RNAP II transcribes a large number of genes with highly variable promoters and interacting factors, which exert fine regulatory control over TIC lability and modifications of RNAP II at different transitional points in the transcription cycle. We review data that illustrate a relatively smooth continuity of RNAP III initiation-elongation-termination and reinitiation toward its function to produce high levels of tRNAs and other RNAs that support growth and development.
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Affiliation(s)
- Aneeshkumar G Arimbasseri
- a Intramural Research Program; Eunice Kennedy Shriver National Institute of Child Health and Human Development; National Institutes of Health; Bethesda, MD USA
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10
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Serruya R, Orlovetskie N, Reiner R, Dehtiar-Zilber Y, Wesolowski D, Altman S, Jarrous N. Human RNase P ribonucleoprotein is required for formation of initiation complexes of RNA polymerase III. Nucleic Acids Res 2015; 43:5442-50. [PMID: 25953854 PMCID: PMC4477669 DOI: 10.1093/nar/gkv447] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 04/24/2015] [Indexed: 12/12/2022] Open
Abstract
Human RNase P is implicated in transcription of small non-coding RNA genes by RNA polymerase III (Pol III), but the precise role of this ribonucleoprotein therein remains unknown. We here show that targeted destruction of HeLa nuclear RNase P inhibits transcription of 5S rRNA genes in whole cell extracts, if this precedes the stage of initiation complex formation. Biochemical purification analyses further reveal that this ribonucleoprotein is recruited to 5S rRNA genes as a part of proficient initiation complexes and the activity persists at reinitiation. Knockdown of RNase P abolishes the assembly of initiation complexes by preventing the formation of the initiation sub-complex of Pol III. Our results demonstrate that the structural intactness, but not the endoribonucleolytic activity per se, of RNase P is critical for the function of Pol III in cells and in extracts.
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Affiliation(s)
- Raphael Serruya
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Natalie Orlovetskie
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Robert Reiner
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Yana Dehtiar-Zilber
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Donna Wesolowski
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Sidney Altman
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Nayef Jarrous
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
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11
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Abstract
Long-terminal repeat (LTR)-retrotransposons generate a copy of their DNA (cDNA) by reverse transcription of their RNA genome in cytoplasmic nucleocapsids. They are widespread in the eukaryotic kingdom and are the evolutionary progenitors of retroviruses [1]. The Ty1 element of the budding yeast Saccharomyces cerevisiae was the first LTR-retrotransposon demonstrated to mobilize through an RNA intermediate, and not surprisingly, is the best studied. The depth of our knowledge of Ty1 biology stems not only from the predominance of active Ty1 elements in the S. cerevisiae genome but also the ease and breadth of genomic, biochemical and cell biology approaches available to study cellular processes in yeast. This review describes the basic structure of Ty1 and its gene products, the replication cycle, the rapidly expanding compendium of host co-factors known to influence retrotransposition and the nature of Ty1's elaborate symbiosis with its host. Our goal is to illuminate the value of Ty1 as a paradigm to explore the biology of LTR-retrotransposons in multicellular organisms, where the low frequency of retrotransposition events presents a formidable barrier to investigations of retrotransposon biology.
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12
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Nguyen NTT, Saguez C, Conesa C, Lefebvre O, Acker J. Identification of proteins associated with RNA polymerase III using a modified tandem chromatin affinity purification. Gene 2015; 556:51-60. [DOI: 10.1016/j.gene.2014.07.070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 07/25/2014] [Accepted: 07/29/2014] [Indexed: 01/12/2023]
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13
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Sanchez-Casalongue ME, Lee J, Diamond A, Shuldiner S, Moir RD, Willis IM. Differential phosphorylation of a regulatory subunit of protein kinase CK2 by target of rapamycin complex 1 signaling and the Cdc-like kinase Kns1. J Biol Chem 2015; 290:7221-33. [PMID: 25631054 DOI: 10.1074/jbc.m114.626523] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Transcriptional regulation of ribosome and tRNA synthesis plays a central role in determining protein synthetic capacity and is tightly controlled in response to nutrient availability and cellular stress. In Saccharomyces cerevisiae, the regulation of ribosome and tRNA synthesis was recently shown to involve the Cdc-like kinase Kns1 and the GSK-3 kinase Mck1. In this study, we explored additional roles for these conserved kinases in processes connected to the target of rapamycin complex 1 (TORC1). We conducted a synthetic chemical-genetic screen in a kns1Δ mck1Δ strain and identified many novel rapamycin-hypersensitive genes. Gene ontology analysis showed enrichment for TORC1-regulated processes (vesicle-mediated transport, autophagy, and regulation of cell size) and identified new connections to protein complexes including the protein kinase CK2. CK2 is considered to be a constitutively active kinase and in budding yeast, the holoenzyme comprises two regulatory subunits, Ckb1 and Ckb2, and two catalytic subunits, Cka1 and Cka2. We show that Ckb1 is differentially phosphorylated in vivo and that Kns1 mediates this phosphorylation when nutrients are limiting and under all tested stress conditions. We determined that the phosphorylation of Ckb1 does not detectably affect the stability of the CK2 holoenzyme but correlates with the reduced occupancy of Ckb1 on tRNA genes after rapamycin treatment. Thus, the differential occupancy of tRNA genes by CK2 is likely to modulate its activation of RNA polymerase III transcription. Our data suggest that TORC1, via its effector kinase Kns1, may regulate the association of CK2 with some of its substrates by phosphorylating Ckb1.
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Affiliation(s)
| | | | | | | | | | - Ian M Willis
- From the Departments of Biochemistry and Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, New York 10461
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14
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Dieci G, Bosio MC, Fermi B, Ferrari R. Transcription reinitiation by RNA polymerase III. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:331-41. [PMID: 23128323 DOI: 10.1016/j.bbagrm.2012.10.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/19/2012] [Accepted: 10/23/2012] [Indexed: 01/11/2023]
Abstract
The retention of transcription proteins at an actively transcribed gene contributes to maintenance of the active transcriptional state and increases the rate of subsequent transcription cycles relative to the initial cycle. This process, called transcription reinitiation, generates the abundant RNAs in living cells. The persistence of stable preinitiation intermediates on activated genes representing at least a subset of basal transcription components has long been recognized as a shared feature of RNA polymerase (Pol) I, II and III-dependent transcription in eukaryotes. Studies of the Pol III transcription machinery and its target genes in eukaryotic genomes over the last fifteen years, has uncovered multiple details on transcription reinitiation. In addition to the basal transcription factors that recruit the polymerase, Pol III itself can be retained on the same gene through multiple transcription cycles by a facilitated recycling pathway. The molecular bases for facilitated recycling are progressively being revealed with advances in structural and functional studies. At the same time, progress in our understanding of Pol III transcriptional regulation in response to different environmental cues points to the specific mechanism of Pol III reinitiation as a key target of signaling pathway regulation of cell growth. This article is part of a Special Issue entitled: Transcription by Odd Pols.
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Affiliation(s)
- Giorgio Dieci
- Dipartimento di Bioscienze, Università degli Studi di Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy.
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15
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Acker J, Conesa C, Lefebvre O. Yeast RNA polymerase III transcription factors and effectors. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:283-95. [PMID: 23063749 DOI: 10.1016/j.bbagrm.2012.10.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 09/27/2012] [Accepted: 10/03/2012] [Indexed: 12/19/2022]
Abstract
Recent data indicate that the well-defined transcription machinery of RNA polymerase III (Pol III) is probably more complex than commonly thought. In this review, we describe the yeast basal transcription factors of Pol III and their involvements in the transcription cycle. We also present a list of proteins detected on genes transcribed by Pol III (class III genes) that might participate in the transcription process. Surprisingly, several of these proteins are involved in RNA polymerase II transcription. Defining the role of these potential new effectors in Pol III transcription in vivo will be the challenge of the next few years. This article is part of a Special Issue entitled: Transcription by Odd Pols.
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Affiliation(s)
- Joël Acker
- CEA, iBiTecS, Gif Sur Yvette, F-91191, France
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16
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Baller JA, Gao J, Stamenova R, Curcio MJ, Voytas DF. A nucleosomal surface defines an integration hotspot for the Saccharomyces cerevisiae Ty1 retrotransposon. Genome Res 2012; 22:704-13. [PMID: 22219511 DOI: 10.1101/gr.129585.111] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Ty1, the most abundant retrotransposon in Saccharomyces cerevisiae, integrates preferentially upstream of genes transcribed by RNA polymerase III (Pol III). Targeting is likely due to interactions between the Ty1 integration complex and a feature of chromatin characteristic of sites of Pol III transcription. To better understand Ty1 targeting determinants, >150,000 Ty1 insertions were mapped onto the S. cerevisiae genome sequence. Logistic regression was used to assess relationships between patterns of Ty1 integration and various genomic features, including genome-wide data sets of histone modifications and transcription-factor binding sites. Nucleosomes were positively associated with Ty1 insertions, and fine-scale mapping of insertions upstream of genes transcribed by Pol III indicated that Ty1 preferentially integrates into nucleosome-bound DNA near the H2A/H2B interface. Outside of genes transcribed by Pol III, Ty1 avoids coding sequences, a pattern that is not due to selection, but rather reflects a preference for nucleosome-rich sites flanking genes. Ty1 insertion sites were also mapped in four mutant lines that affect Ty1 transposition frequency or integration specificity (rrm3Δ, hos2Δ, rtt109Δ, and rad6Δ). Patterns of integration were largely preserved in the mutants, although significantly more insertions into coding sequences were observed in the rad6Δ strain, suggesting a loosening of target specificity in this mutant that lacks an enzyme involved in ubiquitinating H2A. Overall, our data suggest that nucleosomes are necessary for Ty1 integration, and that a secondary factor, likely a histone modification or nucleosome-bound factor enriched at sites of Pol III transcription, determines preferred target sites.
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Affiliation(s)
- Joshua A Baller
- Department of Genetics, Cell Biology & Development and Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA
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17
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Nikitina TV, Tischenko LI, Schulz WA. Recent insights into regulation of transcription by RNA polymerase III and the cellular functions of its transcripts. Biol Chem 2011; 392:395-404. [PMID: 21417954 DOI: 10.1515/bc.2011.049] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The products of transcription by the multisubunit enzyme RNA polymerase III (Pol III), such as 5S rRNA, tRNAs, U6 snRNA, are important for cell growth, proliferation and differentiation. The known range of the Pol III transcriptome has expanded over recent years, and novel functions of the newly discovered and already well known transcripts have been identified, including regulation of stress responses and apoptosis. Furthermore, transcription by Pol III has turned out to be strongly regulated, differing between diverse class III genes, among cell types and under stress conditions. The mechanisms involved in regulation of Pol III transcription are being elucidated and disturbances in that regulation have been implicated in various diseases, including cancer. This review summarizes the novel data on the regulation of RNA polymerase III transcription, including epigenetic and gene specific mechanisms and outlines recent insights into the cellular functions of the Pol III transcriptome, in particular of SINE RNAs.
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Affiliation(s)
- Tatyana V Nikitina
- Department of Biochemistry, Saint-Petersburg State University, St. Petersburg, Russia
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18
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Kassavetis GA, Prakash P, Shim E. The C53/C37 subcomplex of RNA polymerase III lies near the active site and participates in promoter opening. J Biol Chem 2009; 285:2695-706. [PMID: 19940126 DOI: 10.1074/jbc.m109.074013] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The C53 and C37 subunits of RNA polymerase III (pol III) form a subassembly that is required for efficient termination; pol III lacking this subcomplex displays increased processivity of RNA chain elongation. We show that the C53/C37 subcomplex additionally plays a role in formation of the initiation-ready open promoter complex similar to that of the Brf1 N-terminal zinc ribbon domain. In the absence of C53 and C37, the transcription bubble fails to stably propagate to and beyond the transcriptional start site even when the DNA template is supercoiled. The C53/C37 subcomplex also stimulates the formation of an artificially assembled elongation complex from its component DNA and RNA strands. Protein-RNA and protein-DNA photochemical cross-linking analysis places a segment of C53 close to the RNA 3' end and transcribed DNA strand at the catalytic center of the pol III elongation complex. We discuss the implications of these findings for the mechanism of transcriptional termination by pol III and propose a structural as well as functional correspondence between the C53/C37 subcomplex and the RNA polymerase II initiation factor TFIIF.
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Affiliation(s)
- George A Kassavetis
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093-0634, USA.
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19
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Current awareness on yeast. Yeast 2009. [DOI: 10.1002/yea.1619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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20
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Badis G, Chan ET, van Bakel H, Pena-Castillo L, Tillo D, Tsui K, Carlson CD, Gossett AJ, Hasinoff MJ, Warren CL, Gebbia M, Talukder S, Yang A, Mnaimneh S, Terterov D, Coburn D, Li Yeo A, Yeo ZX, Clarke ND, Lieb JD, Ansari AZ, Nislow C, Hughes TR. A library of yeast transcription factor motifs reveals a widespread function for Rsc3 in targeting nucleosome exclusion at promoters. Mol Cell 2009; 32:878-87. [PMID: 19111667 DOI: 10.1016/j.molcel.2008.11.020] [Citation(s) in RCA: 360] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 11/05/2008] [Accepted: 11/26/2008] [Indexed: 01/17/2023]
Abstract
The sequence specificity of DNA-binding proteins is the primary mechanism by which the cell recognizes genomic features. Here, we describe systematic determination of yeast transcription factor DNA-binding specificities. We obtained binding specificities for 112 DNA-binding proteins representing 19 distinct structural classes. One-third of the binding specificities have not been previously reported. Several binding sequences have striking genomic distributions relative to transcription start sites, supporting their biological relevance and suggesting a role in promoter architecture. Among these are Rsc3 binding sequences, containing the core CGCG, which are found preferentially approximately 100 bp upstream of transcription start sites. Mutation of RSC3 results in a dramatic increase in nucleosome occupancy in hundreds of proximal promoters containing a Rsc3 binding element, but has little impact on promoters lacking Rsc3 binding sequences, indicating that Rsc3 plays a broad role in targeting nucleosome exclusion at yeast promoters.
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Affiliation(s)
- Gwenael Badis
- Banting and Best Department of Medical Research, University of Toronto, Toronto, ON M5S 3E1, Canada
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