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Zhao T, Vvedenskaya IO, Lai WKM, Basu S, Pugh BF, Nickels BE, Kaplan CD. Ssl2/TFIIH function in transcription start site scanning by RNA polymerase II in Saccharomyces cerevisiae. eLife 2021; 10:e71013. [PMID: 34652274 PMCID: PMC8589449 DOI: 10.7554/elife.71013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/14/2021] [Indexed: 12/31/2022] Open
Abstract
In Saccharomyces cerevisiae, RNA polymerase II (Pol II) selects transcription start sites (TSSs) by a unidirectional scanning process. During scanning, a preinitiation complex (PIC) assembled at an upstream core promoter initiates at select positions within a window ~40-120 bp downstream. Several lines of evidence indicate that Ssl2, the yeast homolog of XPB and an essential and conserved subunit of the general transcription factor (GTF) TFIIH, drives scanning through its DNA-dependent ATPase activity, therefore potentially controlling both scanning rate and scanning extent (processivity). To address questions of how Ssl2 functions in promoter scanning and interacts with other initiation activities, we leveraged distinct initiation-sensitive reporters to identify novel ssl2 alleles. These ssl2 alleles, many of which alter residues conserved from yeast to human, confer either upstream or downstream TSS shifts at the model promoter ADH1 and genome-wide. Specifically, tested ssl2 alleles alter TSS selection by increasing or narrowing the distribution of TSSs used at individual promoters. Genetic interactions of ssl2 alleles with other initiation factors are consistent with ssl2 allele classes functioning through increasing or decreasing scanning processivity but not necessarily scanning rate. These alleles underpin a residue interaction network that likely modulates Ssl2 activity and TFIIH function in promoter scanning. We propose that the outcome of promoter scanning is determined by two functional networks, the first being Pol II activity and factors that modulate it to determine initiation efficiency within a scanning window, and the second being Ssl2/TFIIH and factors that modulate scanning processivity to determine the width of the scanning widow.
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Affiliation(s)
- Tingting Zhao
- Department of Biological Sciences, University of PittsburghPittsburghUnited States
| | - Irina O Vvedenskaya
- Department of Genetics and Waksman Institute, Rutgers UniversityPiscatawayUnited States
| | - William KM Lai
- Department of Molecular Biology and Genetics, Cornell UniversityIthacaUnited States
| | - Shrabani Basu
- Department of Biological Sciences, University of PittsburghPittsburghUnited States
| | - B Franklin Pugh
- Department of Molecular Biology and Genetics, Cornell UniversityIthacaUnited States
| | - Bryce E Nickels
- Department of Genetics and Waksman Institute, Rutgers UniversityPiscatawayUnited States
| | - Craig D Kaplan
- Department of Biological Sciences, University of PittsburghPittsburghUnited States
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2
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The Mammalian and Yeast A49 and A34 Heterodimers: Homologous but Not the Same. Genes (Basel) 2021; 12:genes12050620. [PMID: 33921963 PMCID: PMC8143541 DOI: 10.3390/genes12050620] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 04/16/2021] [Accepted: 04/20/2021] [Indexed: 11/25/2022] Open
Abstract
Ribosomal RNA synthesis is the rate-limiting step in ribosome biogenesis. In eukaryotes, RNA polymerase I (Pol I) is responsible for transcribing the ribosomal DNA genes that reside in the nucleolus. Aberrations in Pol I activity have been linked to the development of multiple cancers and other genetic diseases. Therefore, it is key that we understand the mechanisms of Pol I transcription. Recent studies have demonstrated that there are many differences between Pol I transcription in yeast and mammals. Our goal is to highlight the similarities and differences between the polymerase-associated factors (PAFs) in yeast and mammalian cells. We focus on the PAF heterodimer A49/34 in yeast and PAF53/49 in mammals. Recent studies have demonstrated that while the structures between the yeast and mammalian orthologs are very similar, they may function differently during Pol I transcription, and their patterns of regulation are different.
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3
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Berkyurek AC, Furlan G, Lampersberger L, Beltran T, Weick E, Nischwitz E, Cunha Navarro I, Braukmann F, Akay A, Price J, Butter F, Sarkies P, Miska EA. The RNA polymerase II subunit RPB-9 recruits the integrator complex to terminate Caenorhabditis elegans piRNA transcription. EMBO J 2021; 40:e105565. [PMID: 33533030 PMCID: PMC7917558 DOI: 10.15252/embj.2020105565] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 12/14/2020] [Accepted: 12/19/2020] [Indexed: 01/03/2023] Open
Abstract
PIWI-interacting RNAs (piRNAs) are genome-encoded small RNAs that regulate germ cell development and maintain germline integrity in many animals. Mature piRNAs engage Piwi Argonaute proteins to silence complementary transcripts, including transposable elements and endogenous genes. piRNA biogenesis mechanisms are diverse and remain poorly understood. Here, we identify the RNA polymerase II (RNA Pol II) core subunit RPB-9 as required for piRNA-mediated silencing in the nematode Caenorhabditis elegans. We show that rpb-9 initiates heritable piRNA-mediated gene silencing at two DNA transposon families and at a subset of somatic genes in the germline. We provide genetic and biochemical evidence that RPB-9 is required for piRNA biogenesis by recruiting the Integrator complex at piRNA genes, hence promoting transcriptional termination. We conclude that, as a part of its rapid evolution, the piRNA pathway has co-opted an ancient machinery for high-fidelity transcription.
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Affiliation(s)
- Ahmet C Berkyurek
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Giulia Furlan
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Lisa Lampersberger
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Toni Beltran
- MRC London Institute of Medical SciencesLondonUK
- Institute of Clinical SciencesImperial College LondonLondonUK
| | - Eva‐Maria Weick
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Present address:
Structural Biology ProgramSloan Kettering InstituteMemorial Sloan Kettering Cancer CenterNew YorkNYUSA
| | - Emily Nischwitz
- Quantitative ProteomicsInstitute of Molecular BiologyMainzGermany
| | - Isabela Cunha Navarro
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Fabian Braukmann
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Alper Akay
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
- Present address:
School of Biological SciencesUniversity of East AngliaNorwich, NorfolkUK
| | - Jonathan Price
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Falk Butter
- Quantitative ProteomicsInstitute of Molecular BiologyMainzGermany
| | - Peter Sarkies
- MRC London Institute of Medical SciencesLondonUK
- Institute of Clinical SciencesImperial College LondonLondonUK
| | - Eric A Miska
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
- Wellcome Sanger InstituteWellcome Trust Genome CampusCambridgeUK
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4
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Qiu C, Jin H, Vvedenskaya I, Llenas JA, Zhao T, Malik I, Visbisky AM, Schwartz SL, Cui P, Čabart P, Han KH, Lai WKM, Metz RP, Johnson CD, Sze SH, Pugh BF, Nickels BE, Kaplan CD. Universal promoter scanning by Pol II during transcription initiation in Saccharomyces cerevisiae. Genome Biol 2020; 21:132. [PMID: 32487207 PMCID: PMC7265651 DOI: 10.1186/s13059-020-02040-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 05/08/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The majority of eukaryotic promoters utilize multiple transcription start sites (TSSs). How multiple TSSs are specified at individual promoters across eukaryotes is not understood for most species. In Saccharomyces cerevisiae, a pre-initiation complex (PIC) comprised of Pol II and conserved general transcription factors (GTFs) assembles and opens DNA upstream of TSSs. Evidence from model promoters indicates that the PIC scans from upstream to downstream to identify TSSs. Prior results suggest that TSS distributions at promoters where scanning occurs shift in a polar fashion upon alteration in Pol II catalytic activity or GTF function. RESULTS To determine the extent of promoter scanning across promoter classes in S. cerevisiae, we perturb Pol II catalytic activity and GTF function and analyze their effects on TSS usage genome-wide. We find that alterations to Pol II, TFIIB, or TFIIF function widely alter the initiation landscape consistent with promoter scanning operating at all yeast promoters, regardless of promoter class. Promoter architecture, however, can determine the extent of promoter sensitivity to altered Pol II activity in ways that are predicted by a scanning model. CONCLUSIONS Our observations coupled with previous data validate key predictions of the scanning model for Pol II initiation in yeast, which we term the shooting gallery. In this model, Pol II catalytic activity and the rate and processivity of Pol II scanning together with promoter sequence determine the distribution of TSSs and their usage.
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Affiliation(s)
- Chenxi Qiu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
- Present Address: Department of Medicine, Division of Translational Therapeutics, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Huiyan Jin
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
| | - Irina Vvedenskaya
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854, USA
- Department of Genetics, Rutgers University, Piscataway, NJ, 08854, USA
| | - Jordi Abante Llenas
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, 77843-3128, USA
- Present Address: Whitaker Biomedical Engineering Institute, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Tingting Zhao
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Indranil Malik
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
- Present Address: Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Alex M Visbisky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Scott L Schwartz
- Genomics and Bioinformatics Service, Texas A&M AgriLife, College Station, TX, 77845, USA
| | - Ping Cui
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
| | - Pavel Čabart
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
- Present Address: First Faculty of Medicine, Charles University, BIOCEV, 252 42, Vestec, Czech Republic
| | - Kang Hoo Han
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA, 16802, USA
| | - William K M Lai
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA, 16802, USA
- Present Address: Department of Molecular Biology and Genetics, 458 Biotechnology, Cornell University, New York, 14853, USA
| | - Richard P Metz
- Genomics and Bioinformatics Service, Texas A&M AgriLife, College Station, TX, 77845, USA
| | - Charles D Johnson
- Genomics and Bioinformatics Service, Texas A&M AgriLife, College Station, TX, 77845, USA
| | - Sing-Hoi Sze
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
- Department of Computer Science and Engineering, Texas A&M University, College Station, TX, 77843-3127, USA
| | - B Franklin Pugh
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA, 16802, USA
- Present Address: Department of Molecular Biology and Genetics, 458 Biotechnology, Cornell University, New York, 14853, USA
| | - Bryce E Nickels
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854, USA
- Department of Genetics, Rutgers University, Piscataway, NJ, 08854, USA
| | - Craig D Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
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5
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Oldfield AJ, Henriques T, Kumar D, Burkholder AB, Cinghu S, Paulet D, Bennett BD, Yang P, Scruggs BS, Lavender CA, Rivals E, Adelman K, Jothi R. NF-Y controls fidelity of transcription initiation at gene promoters through maintenance of the nucleosome-depleted region. Nat Commun 2019; 10:3072. [PMID: 31296853 PMCID: PMC6624317 DOI: 10.1038/s41467-019-10905-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 05/27/2019] [Indexed: 12/22/2022] Open
Abstract
Faithful transcription initiation is critical for accurate gene expression, yet the mechanisms underlying specific transcription start site (TSS) selection in mammals remain unclear. Here, we show that the histone-fold domain protein NF-Y, a ubiquitously expressed transcription factor, controls the fidelity of transcription initiation at gene promoters in mouse embryonic stem cells. We report that NF-Y maintains the region upstream of TSSs in a nucleosome-depleted state while simultaneously protecting this accessible region against aberrant and/or ectopic transcription initiation. We find that loss of NF-Y binding in mammalian cells disrupts the promoter chromatin landscape, leading to nucleosomal encroachment over the canonical TSS. Importantly, this chromatin rearrangement is accompanied by upstream relocation of the transcription pre-initiation complex and ectopic transcription initiation. Further, this phenomenon generates aberrant extended transcripts that undergo translation, disrupting gene expression profiles. These results suggest NF-Y is a central player in TSS selection in metazoans and highlight the deleterious consequences of inaccurate transcription initiation. The mechanisms underlying specific TSS selection in mammals remain unclear. Here the authors show that the ubiquitously expressed transcription factor NF-Y regulate fidelity of transcription initiation at gene promoters, maintaining the region upstream of TSSs in a nucleosome-depleted state, while protecting this region from ectopic transcription initiation.
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Affiliation(s)
- Andrew J Oldfield
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, 27709, USA. .,Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, 34396, France.
| | - Telmo Henriques
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, 27709, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Dhirendra Kumar
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, 27709, USA
| | - Adam B Burkholder
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, 27709, USA
| | - Senthilkumar Cinghu
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, 27709, USA
| | - Damien Paulet
- Department of Computer Science, LIRMM, CNRS et Université de Montpellier, Montpellier, 34095, France.,Institut de Biologie Computationnelle (IBC), Université de Montpellier, Montpellier, 34095, France
| | - Brian D Bennett
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, 27709, USA
| | - Pengyi Yang
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, 27709, USA.,Charles Perkins Centre and School of Mathematics and Statistics, University of Sydney, Sydney, NSW 2006, Australia
| | - Benjamin S Scruggs
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, 27709, USA
| | - Christopher A Lavender
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, 27709, USA
| | - Eric Rivals
- Department of Computer Science, LIRMM, CNRS et Université de Montpellier, Montpellier, 34095, France.,Institut de Biologie Computationnelle (IBC), Université de Montpellier, Montpellier, 34095, France
| | - Karen Adelman
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, 27709, USA. .,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.
| | - Raja Jothi
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, 27709, USA.
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6
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Greber BJ, Nogales E. The Structures of Eukaryotic Transcription Pre-initiation Complexes and Their Functional Implications. Subcell Biochem 2019; 93:143-192. [PMID: 31939151 DOI: 10.1007/978-3-030-28151-9_5] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Transcription is a highly regulated process that supplies living cells with coding and non-coding RNA molecules. Failure to properly regulate transcription is associated with human pathologies, including cancers. RNA polymerase II is the enzyme complex that synthesizes messenger RNAs that are then translated into proteins. In spite of its complexity, RNA polymerase requires a plethora of general transcription factors to be recruited to the transcription start site as part of a large transcription pre-initiation complex, and to help it gain access to the transcribed strand of the DNA. This chapter reviews the structure and function of these eukaryotic transcription pre-initiation complexes, with a particular emphasis on two of its constituents, the multisubunit complexes TFIID and TFIIH. We also compare the overall architecture of the RNA polymerase II pre-initiation complex with those of RNA polymerases I and III, involved in transcription of ribosomal RNA and non-coding RNAs such as tRNAs and snRNAs, and discuss the general, conserved features that are applicable to all eukaryotic RNA polymerase systems.
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Affiliation(s)
- Basil J Greber
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA.
- Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Eva Nogales
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA
- Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
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7
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Babiychuk E, Hoang KT, Vandepoele K, Van De Slijke E, Geelen D, De Jaeger G, Obokata J, Kushnir S. The mutation nrpb1-A325V in the largest subunit of RNA polymerase II suppresses compromised growth of Arabidopsis plants deficient in a function of the general transcription factor IIF. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 89:730-745. [PMID: 27862530 DOI: 10.1111/tpj.13417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 10/31/2016] [Indexed: 06/06/2023]
Abstract
The evolutionarily conserved 12-subunit RNA polymerase II (Pol II) is a central catalytic component that drives RNA synthesis during the transcription cycle that consists of transcription initiation, elongation, and termination. A diverse set of general transcription factors, including a multifunctional TFIIF, govern Pol II selectivity, kinetic properties, and transcription coupling with posttranscriptional processes. Here, we show that TFIIF of Arabidopsis (Arabidopsis thaliana) resembles the metazoan complex that is composed of the TFIIFα and TFIIFβ polypeptides. Arabidopsis has two TFIIFβ subunits, of which TFIIFβ1/MAN1 is essential and TFIIFβ2/MAN2 is not. In the partial loss-of-function mutant allele man1-1, the winged helix domain of Arabidopsis TFIIFβ1/MAN1 was dispensable for plant viability, whereas the cellular organization of the shoot and root apical meristems were abnormal. Forward genetic screening identified an epistatic interaction between the largest Pol II subunit nrpb1-A325V variant and the man1-1 mutation. The suppression of the man1-1 mutant developmental defects by a mutation in Pol II suggests a link between TFIIF functions in Arabidopsis transcription cycle and the maintenance of cellular organization in the shoot and root apical meristems.
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Affiliation(s)
- Elena Babiychuk
- Vale Institute of Technology Sustainable Development, 66055-090, Belém, Pará, Brazil
| | - Khai Trinh Hoang
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, 9000, Ghent, Belgium
- Department of Agriculture and Applied Sciences, Can Tho Technical Economic College, Can Tho, Vietnam
| | - Klaas Vandepoele
- Department of Plant Systems Biology, VIB, 9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
| | - Eveline Van De Slijke
- Department of Plant Systems Biology, VIB, 9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
| | - Danny Geelen
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, 9000, Ghent, Belgium
| | - Geert De Jaeger
- Department of Plant Systems Biology, VIB, 9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
| | - Junichi Obokata
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522, Japan
| | - Sergei Kushnir
- Vale Institute of Technology Sustainable Development, 66055-090, Belém, Pará, Brazil
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8
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Uncoupling Promoter Opening from Start-Site Scanning. Mol Cell 2015; 59:133-8. [PMID: 26073544 DOI: 10.1016/j.molcel.2015.05.021] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 03/08/2015] [Accepted: 05/08/2015] [Indexed: 01/24/2023]
Abstract
Whereas RNA polymerase II (Pol II) transcription start sites (TSSs) occur about 30-35 bp downstream of the TATA box in metazoans, TSSs are located 40-120 bp downstream in S. cerevisiae. Promoter melting begins about 12 bp downstream in all eukaryotes, so Pol II is presumed to "scan" further downstream before starting transcription in yeast. Here we report that removal of the kinase complex TFIIK from TFIIH shifts the TSS in a yeast system upstream to the location observed in metazoans. Conversely, moving the normal TSS to an upstream location enables a high level of TFIIK-independent transcription in the yeast system. We distinguish two stages of the transcription initiation process: bubble formation by TFIIH, which fills the Pol II active center with single-stranded DNA, and subsequent scanning downstream, also driven by TFIIH, which requires displacement of the initial bubble. Omission of TFIIK uncouples the two stages of the process.
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9
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Bick MJ, Malik S, Mustaev A, Darst SA. TFIIB is only ∼9 Å away from the 5'-end of a trimeric RNA primer in a functional RNA polymerase II preinitiation complex. PLoS One 2015; 10:e0119007. [PMID: 25774659 PMCID: PMC4361453 DOI: 10.1371/journal.pone.0119007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 01/27/2015] [Indexed: 11/18/2022] Open
Abstract
Recent X-ray crystallographic studies of Pol II in complex with the general transcription factor (GTF) IIB have begun to provide insights into the mechanism of transcription initiation. These structures have also shed light on the architecture of the transcription preinitiation complex (PIC). However, structural characterization of a functional PIC is still lacking, and even the topological arrangement of the GTFs in the Pol II complex is a matter of contention. We have extended our activity-based affinity crosslinking studies, initially developed to investigate the interaction of bacterial RNA polymerase with σ, to the eukaryotic transcription machinery. Towards that end, we sought to identify GTFs that are within the Pol II active site in a functioning PIC. We provide biochemical evidence that TFIIB is located within ∼9 Å of the -2 site of promoter DNA, where it is positioned to play a role in de novo transcription initiation.
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Affiliation(s)
- Matthew J. Bick
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, United States of America
| | - Sohail Malik
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, United States of America
| | - Arkady Mustaev
- Department of Chemistry and Environmental Sciences, New Jersey Institute of Technology, University Heights, Newark, NJ, United States of America
| | - Seth A. Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, United States of America
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10
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Abstract
Transcription of eukaryotic protein-coding genes commences with the assembly of a conserved initiation complex, which consists of RNA polymerase II (Pol II) and the general transcription factors, at promoter DNA. After two decades of research, the structural basis of transcription initiation is emerging. Crystal structures of many components of the initiation complex have been resolved, and structural information on Pol II complexes with general transcription factors has recently been obtained. Although mechanistic details await elucidation, available data outline how Pol II cooperates with the general transcription factors to bind to and open promoter DNA, and how Pol II directs RNA synthesis and escapes from the promoter.
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11
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Relationships of RNA polymerase II genetic interactors to transcription start site usage defects and growth in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2014; 5:21-33. [PMID: 25380729 PMCID: PMC4291466 DOI: 10.1534/g3.114.015180] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Transcription initiation by RNA Polymerase II (Pol II) is an essential step in gene expression and regulation in all organisms. Initiation requires a great number of factors, and defects in this process can be apparent in the form of altered transcription start site (TSS) selection in Saccharomyces cerevisiae (Baker's yeast). It has been shown previously that TSS selection in S. cerevisiae is altered in Pol II catalytic mutants defective in a conserved active site feature known as the trigger loop. Pol II trigger loop mutants show growth phenotypes in vivo that correlate with biochemical defects in vitro and exhibit wide-ranging genetic interactions. We assessed how Pol II mutant growth phenotypes and TSS selection in vivo are modified by Pol II genetic interactors to estimate the relationship between altered TSS selection in vivo and organismal fitness of Pol II mutants. We examined whether the magnitude of TSS selection defects could be correlated with Pol II mutant-transcription factor double mutant phenotypes. We observed broad genetic interactions among Pol II trigger loop mutants and General Transcription Factor (GTF) alleles, with reduced-activity Pol II mutants especially sensitive to defects in TFIIB. However, Pol II mutant growth defects could be uncoupled from TSS selection defects in some Pol II allele-GTF allele double mutants, whereas a number of other Pol II genetic interactors did not influence ADH1 start site selection alone or in combination with Pol II mutants. Initiation defects are likely only partially responsible for Pol II allele growth phenotypes, with some Pol II genetic interactors able to exacerbate Pol II mutant growth defects while leaving initiation at a model TSS selection promoter unaffected.
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12
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Transcription factors IIS and IIF enhance transcription efficiency by differentially modifying RNA polymerase pausing dynamics. Proc Natl Acad Sci U S A 2014; 111:3419-24. [PMID: 24550488 DOI: 10.1073/pnas.1401611111] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Transcription factors IIS (TFIIS) and IIF (TFIIF) are known to stimulate transcription elongation. Here, we use a single-molecule transcription elongation assay to study the effects of both factors. We find that these transcription factors enhance overall transcription elongation by reducing the lifetime of transcriptional pauses and that TFIIF also decreases the probability of pause entry. Furthermore, we observe that both factors enhance the processivity of RNA polymerase II through the nucleosomal barrier. The effects of TFIIS and TFIIF are quantitatively described using the linear Brownian ratchet kinetic model for transcription elongation and the backtracking model for transcriptional pauses, modified to account for the effects of the transcription factors. Our findings help elucidate the molecular mechanisms by which transcription factors modulate gene expression.
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13
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From structure to systems: high-resolution, quantitative genetic analysis of RNA polymerase II. Cell 2013; 154:775-88. [PMID: 23932120 DOI: 10.1016/j.cell.2013.07.033] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 05/16/2013] [Accepted: 07/22/2013] [Indexed: 01/22/2023]
Abstract
RNA polymerase II (RNAPII) lies at the core of dynamic control of gene expression. Using 53 RNAPII point mutants, we generated a point mutant epistatic miniarray profile (pE-MAP) comprising ∼60,000 quantitative genetic interactions in Saccharomyces cerevisiae. This analysis enabled functional assignment of RNAPII subdomains and uncovered connections between individual regions and other protein complexes. Using splicing microarrays and mutants that alter elongation rates in vitro, we found an inverse relationship between RNAPII speed and in vivo splicing efficiency. Furthermore, the pE-MAP classified fast and slow mutants that favor upstream and downstream start site selection, respectively. The striking coordination of polymerization rate with transcription initiation and splicing suggests that transcription rate is tuned to regulate multiple gene expression steps. The pE-MAP approach provides a powerful strategy to understand other multifunctional machines at amino acid resolution.
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14
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Hybrid electron microscopy-FRET imaging localizes the dynamical C-terminus of Tfg2 in RNA polymerase II-TFIIF with nanometer precision. J Struct Biol 2013; 184:52-62. [PMID: 23732819 DOI: 10.1016/j.jsb.2013.05.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 05/06/2013] [Accepted: 05/21/2013] [Indexed: 01/23/2023]
Abstract
TFIIF-a general transcription factor comprising two conserved subunits can associate with RNA polymerase II (RNAPII) tightly to regulate the synthesis of messenger RNA in eukaryotes. Herein, a hybrid method that combines electron microscopy (EM) and Förster resonance energy transfer (FRET) is described and used to localize the C-terminus of the second TFIIF subunit (Tfg2) in the architecture of RNAPII-TFIIF. In the first stage, a poly-histidine tag appended to the Tfg2 C-terminus was labeled with nickel-NTA nanogold and a seven-step single particle EM protocol was devised to obtain the region accessible by the nanogold in 3D, suggesting the Tfg2 C-terminus is proximal to the clamp of RNAPII. Next, the C-termini of the Rpb2 and the Rpb4 subunits of RNAPII, adjacent to the clamp, were selected for placing FRET satellites to enable the nano-positioning (NP) analysis, by which the localization precision was improved such that the Tfg2 C-terminus was found to dwell on the clamp ridge but could move to the clamp top during transcription. Because the tag receptive to the EM or FRET probes can be readily introduced to any protein subunit, this hybrid approach is generally applicable to complement cryo-EM study of many protein complexes to nanometer precision.
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15
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He Y, Fang J, Taatjes DJ, Nogales E. Structural visualization of key steps in human transcription initiation. Nature 2013; 495:481-6. [PMID: 23446344 PMCID: PMC3612373 DOI: 10.1038/nature11991] [Citation(s) in RCA: 201] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 02/07/2013] [Indexed: 01/22/2023]
Abstract
Eukaryotic transcription initiation requires the assembly of general transcription factors into a pre-initiation complex that ensures the accurate loading of RNA polymerase II (Pol II) at the transcription start site. The molecular mechanism and function of this assembly have remained elusive due to lack of structural information. Here we have used an in vitro reconstituted system to study the stepwise assembly of human TBP, TFIIA, TFIIB, Pol II, TFIIF, TFIIE and TFIIH onto promoter DNA using cryo-electron microscopy. Our structural analyses provide pseudo-atomic models at various stages of transcription initiation that illuminate critical molecular interactions, including how TFIIF engages Pol II and promoter DNA to stabilize both the closed pre-initiation complex and the open-promoter complex, and to regulate start--initiation complexes, combined with the localization of the TFIIH helicases XPD and XPB, support a DNA translocation model of XPB and explain its essential role in promoter opening.
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Affiliation(s)
- Yuan He
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Jie Fang
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Dylan J. Taatjes
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303
| | - Eva Nogales
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720,Howard Hughes Medical Institute, University of California, Berkeley, CA 94720,QB3 Institute and Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720,Correspondence:
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16
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RNA polymerase II mutations conferring defects in poly(A) site cleavage and termination in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2013; 3:167-80. [PMID: 23390594 PMCID: PMC3564978 DOI: 10.1534/g3.112.004531] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 11/27/2012] [Indexed: 01/06/2023]
Abstract
Transcription termination by RNA polymerase (Pol) II is an essential but poorly understood process. In eukaryotic nuclei, the 3′ ends of mRNAs are generated by cleavage and polyadenylation, and the same sequence elements that specify that process are required for downstream release of the polymerase from the DNA. Although Pol II is known to bind proteins required for both events, few studies have focused on Pol II mutations as a means to uncover the mechanisms that couple polyadenylation and termination. We performed a genetic screen in the yeast Saccharomyces cerevisiae to isolate mutations in the N-terminal half of Rpb2, the second largest Pol II subunit, that conferred either a decreased or increased response to a well-characterized poly(A) site. Most of the mutant alleles encoded substitutions affecting either surface residues or conserved active site amino acids at positions important for termination by other RNA polymerases. Reverse transcription polymerase chain reaction experiments revealed that transcript cleavage at the poly(A) site was impaired in both classes of increased readthrough mutants. Transcription into downstream sequences beyond where termination normally occurs was also probed. Although most of the tested readthrough mutants showed a reduction in termination concomitant with the reduced poly(A) usage, these processes were uncoupled in at least one mutant strain. Several rpb2 alleles were found to be similar or identical to published mutants associated with defective TFIIF function. Tests of these and additional mutations known to impair Rpb2−TFIIF interactions revealed similar decreased readthrough phenotypes, suggesting that TFIIF may have a role in 3′ end formation and termination.
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17
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Kaplan CD. Basic mechanisms of RNA polymerase II activity and alteration of gene expression in Saccharomyces cerevisiae. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:39-54. [PMID: 23022618 DOI: 10.1016/j.bbagrm.2012.09.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 09/18/2012] [Accepted: 09/20/2012] [Indexed: 01/12/2023]
Abstract
Transcription by RNA polymerase II (Pol II), and all RNA polymerases for that matter, may be understood as comprising two cycles. The first cycle relates to the basic mechanism of the transcription process wherein Pol II must select the appropriate nucleoside triphosphate (NTP) substrate complementary to the DNA template, catalyze phosphodiester bond formation, and translocate to the next position on the DNA template. Performing this cycle in an iterative fashion allows the synthesis of RNA chains that can be over one million nucleotides in length in some larger eukaryotes. Overlaid upon this enzymatic cycle, transcription may be divided into another cycle of three phases: initiation, elongation, and termination. Each of these phases has a large number of associated transcription factors that function to promote or regulate the gene expression process. Complicating matters, each phase of the latter transcription cycle are coincident with cotranscriptional RNA processing events. Additionally, transcription takes place within a highly dynamic and regulated chromatin environment. This chromatin environment is radically impacted by active transcription and associated chromatin modifications and remodeling, while also functioning as a major platform for Pol II regulation. This review will focus on our basic knowledge of the Pol II transcription mechanism, and how altered Pol II activity impacts gene expression in vivo in the model eukaryote Saccharomyces cerevisiae. This article is part of a Special Issue entitled: RNA Polymerase II Transcript Elongation.
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Affiliation(s)
- Craig D Kaplan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA.
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18
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Liu X, Bushnell DA, Kornberg RD. RNA polymerase II transcription: structure and mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:2-8. [PMID: 23000482 DOI: 10.1016/j.bbagrm.2012.09.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 09/07/2012] [Indexed: 01/25/2023]
Abstract
A minimal RNA polymerase II (pol II) transcription system comprises the polymerase and five general transcription factors (GTFs) TFIIB, -D, -E, -F, and -H. The addition of Mediator enables a response to regulatory factors. The GTFs are required for promoter recognition and the initiation of transcription. Following initiation, pol II alone is capable of RNA transcript elongation and of proofreading. Structural studies reviewed here reveal roles of GTFs in the initiation process and shed light on the transcription elongation mechanism. This article is part of a Special Issue entitled: RNA Polymerase II Transcript Elongation.
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Affiliation(s)
- Xin Liu
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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19
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Luse DS. Rethinking the role of TFIIF in transcript initiation by RNA polymerase II. Transcription 2012; 3:156-9. [PMID: 22771986 DOI: 10.4161/trns.20725] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
TFIIF is considered to be a general transcription factor, based on the fact that it is essential for assembly of RNA polymerase II preinitiation complexes on fully double-stranded templates in vitro. Existing models assign various tasks to TFIIF during preinitiation complex formation and transcript initiation. Recent results do not support all aspects of those models but they do emphasize the significance of the interaction of TFIIF and TFIIB. Other recent findings raise the possibility that a fraction of RNA polymerase II transcription complex assembly proceeds through a pathway that is independent of TFIIF.
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20
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Yang C, Ponticelli AS. Evidence that RNA polymerase II and not TFIIB is responsible for the difference in transcription initiation patterns between Saccharomyces cerevisiae and Schizosaccharomyces pombe. Nucleic Acids Res 2012; 40:6495-507. [PMID: 22510268 PMCID: PMC3413132 DOI: 10.1093/nar/gks323] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The basal eukaryotic transcription machinery for protein coding genes is highly conserved from unicellular yeast to higher eukaryotes. Whereas TATA-containing promoters in human cells usually contain a single transcription start site (TSS) located ∼30 bp downstream of the TATA element, transcription in the yeast Schizosaccharomyces pombe and Saccharomyces cerevisiae typically initiates at multiple sites within a window ranging from 30 to 70 bp or 40 to 200 bp downstream of a TATA element, respectively. By exchanging highly purified factors between reconstituted S. pombe and S. cerevisiae transcription systems, we confirmed previous observations that the dual exchange of RNA polymerase II (RNAPII) and transcription factor IIB (TFIIB) confer the distinct initiation patterns between these yeast species. Surprisingly, however, further genetic and biochemical assays of TFIIB chimeras revealed that TFIIB and the proposed B-finger/reader domain do not play a role in determining the distinct initiation patterns between S. pombe and S. cerevisiae, but rather, these patterns are solely due to differences in RNAPII. These results are discussed within the context of a proposed model for the mechanistic coupling of the efficiency of early phosphodiester bond formation during productive TSS utilization and intrinsic elongation proficiency.
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Affiliation(s)
- Chen Yang
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York, Buffalo, NY 14214-3000, USA
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21
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Kaplan CD, Jin H, Zhang IL, Belyanin A. Dissection of Pol II trigger loop function and Pol II activity-dependent control of start site selection in vivo. PLoS Genet 2012; 8:e1002627. [PMID: 22511879 PMCID: PMC3325174 DOI: 10.1371/journal.pgen.1002627] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Accepted: 02/15/2012] [Indexed: 12/27/2022] Open
Abstract
Structural and biochemical studies have revealed the importance of a conserved, mobile domain of RNA Polymerase II (Pol II), the Trigger Loop (TL), in substrate selection and catalysis. The relative contributions of different residues within the TL to Pol II function and how Pol II activity defects correlate with gene expression alteration in vivo are unknown. Using Saccharomyces cerevisiae Pol II as a model, we uncover complex genetic relationships between mutated TL residues by combinatorial analysis of multiply substituted TL variants. We show that in vitro biochemical activity is highly predictive of in vivo transcription phenotypes, suggesting direct relationships between phenotypes and Pol II activity. Interestingly, while multiple TL residues function together to promote proper transcription, individual residues can be separated into distinct functional classes likely relevant to the TL mechanism. In vivo, Pol II activity defects disrupt regulation of the GTP-sensitive IMD2 gene, explaining sensitivities to GTP-production inhibitors, but contrasting with commonly cited models for this sensitivity in the literature. Our data provide support for an existing model whereby Pol II transcriptional activity provides a proxy for direct sensing of NTP levels in vivo leading to IMD2 activation. Finally, we connect Pol II activity to transcription start site selection in vivo, implicating the Pol II active site and transcription itself as a driver for start site scanning, contravening current models for this process. Transcription by multisubunit RNA polymerases (msRNAPs) is essential for all kingdoms of life. A conserved region within msRNAPs called the trigger loop (TL) is critical for selection of nucleotide substrates and activity. We present analysis of the RNA Polymerase II (Pol II) TL from the model eukaryote Saccharomyces cerevisiae. Our experiments reveal how TL residues differentially contribute to viability and transcriptional activity. We find that in vivo growth phenotypes correlate with severity of transcriptional defects and that changing Pol II activity to either faster or slower than wild type causes specific transcription defects. We identify transcription start site selection as sensitive to Pol II catalytic activity, proposing that RNA synthesis (an event downstream of many steps in the initiation process) contributes to where productive transcription occurs. Pol II transcription activity was excluded from previous models for selection of productive Pol II start sites. Finally, drug sensitivity data have been widely interpreted to indicate that Pol II mutants defective in elongation properties are sensitized to reduction in GTP levels (a Pol II substrate). Our data suggest an alternate explanation, that sensitivity to decreased GTP levels may be explained in light of Pol II mutant transcriptional start site defects.
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Affiliation(s)
- Craig D Kaplan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America.
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22
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Transcriptional regulation in Saccharomyces cerevisiae: transcription factor regulation and function, mechanisms of initiation, and roles of activators and coactivators. Genetics 2012; 189:705-36. [PMID: 22084422 DOI: 10.1534/genetics.111.127019] [Citation(s) in RCA: 237] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Here we review recent advances in understanding the regulation of mRNA synthesis in Saccharomyces cerevisiae. Many fundamental gene regulatory mechanisms have been conserved in all eukaryotes, and budding yeast has been at the forefront in the discovery and dissection of these conserved mechanisms. Topics covered include upstream activation sequence and promoter structure, transcription factor classification, and examples of regulated transcription factor activity. We also examine advances in understanding the RNA polymerase II transcription machinery, conserved coactivator complexes, transcription activation domains, and the cooperation of these factors in gene regulatory mechanisms.
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23
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Kilpatrick AM, Koharudin LMI, Calero GA, Gronenborn AM. Structural and binding studies of the C-terminal domains of yeast TFIIF subunits Tfg1 and Tfg2. Proteins 2011; 80:519-29. [PMID: 22095626 DOI: 10.1002/prot.23217] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 09/12/2011] [Accepted: 09/27/2011] [Indexed: 12/13/2022]
Abstract
The general transcription factor TFIIF plays essential roles at several steps during eukaryotic transcription. While several studies have offered insights into the structure/function relationship in human TFIIF, much less is known about the yeast system. Here, we describe the first NMR structural and binding studies of the C-terminal domains (CTDs) of Tfg1 and Tfg2 subunits of Saccharomyces cerevisiae TFIIF. We used the program CS-ROSETTA to determine the three-dimensional folds of these domains in solution, and performed binding studies with DNA and protein targets. CS-ROSETTA models indicate that the Tfg1 and Tfg2 C-terminal domains have winged-helix architectures, similar to the human homologs. We showed that both Tfg1 and Tfg2 CTDs interact with double-stranded DNA oligonucleotides, and mapped the DNA binding interfaces using solution NMR. Tfg1-CTD, but not Tfg2-CTD, also binds to yeast FCP1, an RNA polymerase II-specific phosphatase, and we delineated the interaction surface with the CTD of FCP1. Our results provide insights into the structural basis of yeast TFIIF function and the differential roles of Tfg1 and Tfg2 subunits during transcription.
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Affiliation(s)
- Adina M Kilpatrick
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
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24
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Goel S, Krishnamurthy S, Hampsey M. Mechanism of start site selection by RNA polymerase II: interplay between TFIIB and Ssl2/XPB helicase subunit of TFIIH. J Biol Chem 2011; 287:557-567. [PMID: 22081613 DOI: 10.1074/jbc.m111.281576] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
TFIIB is essential for transcription initiation by RNA polymerase II. TFIIB also cross-links to terminator regions and is required for gene loops that juxtapose promoter-terminator elements in a transcription-dependent manner. The Saccharomyces cerevisiae sua7-1 mutation encodes an altered form of TFIIB (E62K) that is defective for both start site selection and gene looping. Here we report the isolation of an ssl2 mutant, encoding an altered form of TFIIH, as a suppressor of the cold-sensitive growth defect of the sua7-1 mutation. Ssl2 (Rad25) is orthologous to human XPB and is a member of the SF2 family of ATP-dependent DNA helicases. The ssl2 suppressor allele encodes an arginine replacement of the conserved histidine residue (H508R) located within the DEVH-containing helicase domain. In addition to suppressing the TFIIB E62K growth defect, Ssl2 H508R partially restores both normal start site selection and gene looping. Moreover, Ssl2, like TFIIB, associates with promoter and terminator regions, and the diminished association of TFIIB E62K with the PMA1 terminator is restored by the Ssl2 H508R suppressor. These results define a novel, functional interaction between TFIIB and Ssl2 that affects start site selection and gene looping.
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Affiliation(s)
- Shivani Goel
- Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | | | - Michael Hampsey
- Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854.
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25
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Transcription factor TFIIF is not required for initiation by RNA polymerase II, but it is essential to stabilize transcription factor TFIIB in early elongation complexes. Proc Natl Acad Sci U S A 2011; 108:15786-91. [PMID: 21896726 DOI: 10.1073/pnas.1104591108] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Transcription factors TFIIB and TFIIF are both required for RNA polymerase II preinitiation complex (PIC) assembly, but their roles at and downstream of initiation are not clear. We now show that TFIIF phosphorylated by casein kinase 2 remains competent to support PIC assembly but is not stably retained in the PIC. PICs completely lacking TFIIF are not defective in initiation or subsequent promoter clearance, demonstrating that TFIIF is not required for initiation or clearance. Lack of TFIIF in the PIC reduces transcription levels at some promoters, coincident with reduced retention of TFIIB. TFIIB is normally associated with the early elongation complex and is only destabilized at +12 to +13. However, if TFIIF is not retained in the PIC, TFIIB can be lost immediately after initiation. TFIIF therefore has an important role in stabilizing TFIIB within the PIC and after transcription initiates.
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26
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Újvári A, Pal M, Luse DS. The functions of TFIIF during initiation and transcript elongation are differentially affected by phosphorylation by casein kinase 2. J Biol Chem 2011; 286:23160-7. [PMID: 21566144 DOI: 10.1074/jbc.m110.205658] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The RNA polymerase II (pol II) initiation and elongation factor elongation factor TFIIF can be extensively phosphorylated in vivo, although the significance of this modification has not been clear. We now show that phosphorylation of recombinant TFIIF by casein kinase 2 (CK2) reduces or eliminates some of the functions of TFIIF while paradoxically leaving others intact. Phospho-IIF is fully functional in binding to free pol II and is able to support the initiation of transcription. However, the phosphorylated factor does not bind to stalled elongation complexes as measured in a gel mobility shift assay. Significantly, phosphorylation strongly reduces (or for some truncated versions of RAP74, eliminates) stimulation of transcript elongation by TFIIF. Thus, although TFIIF must participate at the initiation of transcription, its ability to continue its association with pol II and stimulate transcript elongation can be specifically regulated by CK2. This is particularly interesting because CK2 is required for initiation at a subset of pol II promoters. Modulation of TFIIF function could be important in controlling promoter-proximal pausing by pol II during the early stage of transcript elongation.
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Affiliation(s)
- Andrea Újvári
- Department of Molecular Genetics, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195, USA
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27
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Kasahara K, Ohyama Y, Kokubo T. Hmo1 directs pre-initiation complex assembly to an appropriate site on its target gene promoters by masking a nucleosome-free region. Nucleic Acids Res 2011; 39:4136-50. [PMID: 21288884 PMCID: PMC3105432 DOI: 10.1093/nar/gkq1334] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Saccharomyces cerevisiae Hmo1 binds to the promoters of ∼70% of ribosomal protein genes (RPGs) at high occupancy, but is observed at lower occupancy on the remaining RPG promoters. In Δhmo1 cells, the transcription start site (TSS) of the Hmo1-enriched RPS5 promoter shifted upstream, while the TSS of the Hmo1-limited RPL10 promoter did not shift. Analyses of chimeric RPS5/RPL10 promoters revealed a region between the RPS5 upstream activating sequence (UAS) and core promoter, termed the intervening region (IVR), responsible for strong Hmo1 binding and an upstream TSS shift in Δhmo1 cells. Chromatin immunoprecipitation analyses showed that the RPS5-IVR resides within a nucleosome-free region and that pre-initiation complex (PIC) assembly occurs at a site between the IVR and a nucleosome overlapping the TSS (+1 nucleosome). The PIC assembly site was shifted upstream in Δhmo1 cells on this promoter, indicating that Hmo1 normally masks the RPS5-IVR to prevent PIC assembly at inappropriate site(s). This novel mechanism ensures accurate transcriptional initiation by delineating the 5′- and 3′-boundaries of the PIC assembly zone.
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Affiliation(s)
- Koji Kasahara
- Division of Molecular and Cellular Biology, Graduate School of Nanobioscience, Yokohama City University, Yokohama 230-0045, Japan.
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28
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Chen ZA, Jawhari A, Fischer L, Buchen C, Tahir S, Kamenski T, Rasmussen M, Lariviere L, Bukowski-Wills JC, Nilges M, Cramer P, Rappsilber J. Architecture of the RNA polymerase II-TFIIF complex revealed by cross-linking and mass spectrometry. EMBO J 2010; 29:717-26. [PMID: 20094031 PMCID: PMC2810376 DOI: 10.1038/emboj.2009.401] [Citation(s) in RCA: 316] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Accepted: 12/10/2009] [Indexed: 11/09/2022] Open
Abstract
Higher-order multi-protein complexes such as RNA polymerase II (Pol II) complexes with transcription initiation factors are often not amenable to X-ray structure determination. Here, we show that protein cross-linking coupled to mass spectrometry (MS) has now sufficiently advanced as a tool to extend the Pol II structure to a 15-subunit, 670 kDa complex of Pol II with the initiation factor TFIIF at peptide resolution. The N-terminal regions of TFIIF subunits Tfg1 and Tfg2 form a dimerization domain that binds the Pol II lobe on the Rpb2 side of the active centre cleft near downstream DNA. The C-terminal winged helix (WH) domains of Tfg1 and Tfg2 are mobile, but the Tfg2 WH domain can reside at the Pol II protrusion near the predicted path of upstream DNA in the initiation complex. The linkers between the dimerization domain and the WH domains in Tfg1 and Tfg2 are located to the jaws and protrusion, respectively. The results suggest how TFIIF suppresses non-specific DNA binding and how it helps to recruit promoter DNA and to set the transcription start site. This work establishes cross-linking/MS as an integrated structure analysis tool for large multi-protein complexes.
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Affiliation(s)
- Zhuo Angel Chen
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, The University of Edinburgh, Edinburgh, UK
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29
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Eichner J, Chen HT, Warfield L, Hahn S. Position of the general transcription factor TFIIF within the RNA polymerase II transcription preinitiation complex. EMBO J 2009; 29:706-16. [PMID: 20033062 DOI: 10.1038/emboj.2009.386] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Accepted: 12/01/2009] [Indexed: 11/09/2022] Open
Abstract
The RNA polymerase (pol) II general transcription factor TFIIF functions at several steps in transcription initiation including preinitiation complex (PIC) formation and start site selection. We find that two structured TFIIF domains bind Pol II at separate locations far from the active site with the TFIIF dimerization domain on the Pol II lobe and the winged helix domain of the TFIIF small subunit Tfg2 above the Pol II protrusion where it may interact with upstream promoter DNA. Binding of the winged helix to the protrusion is PIC specific. Anchoring of these two structured TFIIF domains at separate sites locates an essential and unstructured region of Tfg2 near the Pol II active site cleft where it may interact with flexible regions of Pol II and the general factor TFIIB to promote initiation and start site selection. Consistent with this mechanism, mutations far from the enzyme active site, which alter the binding of either structured TFIIF domains to Pol II, have similar defects in transcription start site usage.
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Affiliation(s)
- Jesse Eichner
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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30
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Yang C, Khaperskyy DA, Hou M, Ponticelli AS. Improved methods for expression and purification of Saccharomyces cerevisiae TFIIF and TFIIH; identification of a functional Escherichia coli promoter and internal translation initiation within the N-terminal coding region of the TFIIF TFG1 subunit. Protein Expr Purif 2009; 70:172-8. [PMID: 19818408 DOI: 10.1016/j.pep.2009.09.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 09/28/2009] [Accepted: 09/29/2009] [Indexed: 11/26/2022]
Abstract
The basal RNA polymerase II (RNAPII) transcription machinery is composed of RNAPII and the general transcription factors (TF) TATA binding protein (TBP), TFIIB, TFIIE, TFIIF and TFIIH. Due to the powerful genetic and molecular approaches that can be utilized, the budding yeast Saccharomyces cerevisiae has proven to be an invaluable model system for studies of the mechanisms of RNAPII transcription. Complementary biochemical studies of the S. cerevisiae basal transcription machinery, however, have been hampered by difficulties in the purification of TFIIF and TFIIH, most notably due to the severe toxicity of the TFIIF Tfg1 subunit in Escherichia coli and the complexity of the purification scheme for native TFIIH. Here, we report the elimination of TFG1-associated toxicity in E. coli, the identification and removal of a functional E. coli promoter and internal translation initiation within the N-terminal coding region of TFG1, and the efficient production and two-step purification of recombinant TFIIF complexes. We also report conditions for the efficient two-step tandem affinity purification (TAP) of holo-TFIIH, core TFIIH and TFIIK complexes from yeast whole cell extracts.
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Affiliation(s)
- Chen Yang
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York, Buffalo, NY 14214-3000, USA
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Süel KE, Chook YM. Kap104p imports the PY-NLS-containing transcription factor Tfg2p into the nucleus. J Biol Chem 2009; 284:15416-24. [PMID: 19366694 DOI: 10.1074/jbc.m809384200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A previous bioinformatics study identified a putative PY-NLS in the yeast transcription factor Tfg2p (Suel, K. E., Gu, H., and Chook, Y. M. (2008) PLoS Biol. 6, e137). In this study, we validate Tfg2p as a Kap104p substrate and examine the energetic organization of its PY-NLS. The Tfg2p PY-NLS can target a heterologous protein into the cell nucleus through interactions with Kap104p. Surprisingly, full-length Tfg2p is still localized to the nucleus of Kap104p temperature-sensitive cells and, similarly, Tfg2p with a mutated PY-NLS is nuclear in wild-type cells. Other Karyopherinbetas (Kapbetas) such as Kap108p and Kap120p also bind Tfg2p and may import it into the nucleus. More importantly, we demonstrate that Tfg2p is retained in the nucleus through DNA binding. Mutations of DNA binding residues relieve nuclear retention and unmask the role of Kap104p in Tfg2p nuclear import. More generally, steady-state localization of a nuclear protein is dictated by its nuclear import and export activities as well as its interactions in the nucleus and the cytoplasm.
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Affiliation(s)
- Katherine E Süel
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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32
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Abstract
Knowing the precise locations of nucleosomes in a genome is key to understanding how genes are regulated. Recent 'next generation' ChIP-chip and ChIP-Seq technologies have accelerated our understanding of the basic principles of chromatin organization. Here we discuss what high-resolution genome-wide maps of nucleosome positions have taught us about how nucleosome positioning demarcates promoter regions and transcriptional start sites, and how the composition and structure of promoter nucleosomes facilitate or inhibit transcription. A detailed picture is starting to emerge of how diverse factors, including underlying DNA sequences and chromatin remodelling complexes, influence nucleosome positioning.
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Affiliation(s)
- Cizhong Jiang
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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33
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Functions of Saccharomyces cerevisiae TFIIF during transcription start site utilization. Mol Cell Biol 2008; 28:3757-66. [PMID: 18362165 DOI: 10.1128/mcb.02272-07] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies have shown that substitutions in the Tfg1 or Tfg2 subunits of Saccharomyces cerevisiae transcription factor IIF (TFIIF) can cause upstream shifts in start site utilization, resulting in initiation patterns that more closely resemble those of higher eukaryotes. In this study, we report the results from multiple biochemical assays analyzing the activities of wild-type yeast TFIIF and the TFIIF Tfg1 mutant containing the E346A substitution (Tfg1-E346A). We demonstrate that TFIIF stimulates formation of the first two phosphodiester bonds and dramatically stabilizes a short RNA-DNA hybrid in the RNA polymerase II (RNAPII) active center and, importantly, that the Tfg1-E346A substitution coordinately enhances early bond formation and the processivity of early elongation in vitro. These results are discussed within a proposed model for the role of yeast TFIIF in modulating conformational changes in the RNAPII active center during initiation and early elongation.
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Kasahara K, Ki S, Aoyama K, Takahashi H, Kokubo T. Saccharomyces cerevisiae HMO1 interacts with TFIID and participates in start site selection by RNA polymerase II. Nucleic Acids Res 2008; 36:1343-57. [PMID: 18187511 PMCID: PMC2275077 DOI: 10.1093/nar/gkm1068] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Saccharomyces cerevisiae HMO1, a high mobility group B (HMGB) protein, associates with the rRNA locus and with the promoters of many ribosomal protein genes (RPGs). Here, the Sos recruitment system was used to show that HMO1 interacts with TBP and the N-terminal domain (TAND) of TAF1, which are integral components of TFIID. Biochemical studies revealed that HMO1 copurifies with TFIID and directly interacts with TBP but not with TAND. Deletion of HMO1 (Δhmo1) causes a severe cold-sensitive growth defect and decreases transcription of some TAND-dependent genes. Δhmo1 also affects TFIID occupancy at some RPG promoters in a promoter-specific manner. Interestingly, over-expression of HMO1 delays colony formation of taf1 mutants lacking TAND (taf1ΔTAND), but not of the wild-type strain, indicating a functional link between HMO1 and TAND. Furthermore, Δhmo1 exhibits synthetic growth defects in some spt15 (TBP) and toa1 (TFIIA) mutants while it rescues growth defects of some sua7 (TFIIB) mutants. Importantly, Δhmo1 causes an upstream shift in transcriptional start sites of RPS5, RPS16A, RPL23B, RPL27B and RPL32, but not of RPS31, RPL10, TEF2 and ADH1, indicating that HMO1 may participate in start site selection of a subset of class II genes presumably via its interaction with TFIID.
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Affiliation(s)
- Koji Kasahara
- Division of Molecular and Cellular Biology, International Graduate School of Arts and Sciences, Yokohama City University, Yokohama, 230-0045, Japan
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35
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36
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Chen HT, Warfield L, Hahn S. The positions of TFIIF and TFIIE in the RNA polymerase II transcription preinitiation complex. Nat Struct Mol Biol 2007; 14:696-703. [PMID: 17632521 PMCID: PMC2483787 DOI: 10.1038/nsmb1272] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Accepted: 06/14/2007] [Indexed: 11/09/2022]
Abstract
We incorporated the non-natural photoreactive amino acid p-benzoyl-L-phenylalanine (Bpa) into the RNA polymerase II (Pol II) surface surrounding the central cleft formed by the Rpb1 and Rpb2 subunits. Photo-cross-linking of preinitiation complexes (PICs) with these Pol II derivatives and hydroxyl-radical cleavage assays revealed that the TFIIF dimerization domain interacts with the Rpb2 lobe and protrusion domains adjacent to Rpb9, while TFIIE cross-links to the Rpb1 clamp domain on the opposite side of the Pol II central cleft. Mutations in the Rpb2 lobe and protrusion domains alter both Pol II-TFIIF binding and the transcription start site, a phenotype associated with mutations in TFIIF, Rpb9 and TFIIB. Together with previous biochemical and structural studies, these findings illuminate the structural organization of the PIC and the network of protein-protein interactions involved in transcription start site selection.
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Affiliation(s)
- Hung-Ta Chen
- Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N., Mailstop A1-162, Seattle, Washington 98109, USA
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37
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Zaros C, Briand JF, Boulard Y, Labarre-Mariotte S, Garcia-Lopez MC, Thuriaux P, Navarro F. Functional organization of the Rpb5 subunit shared by the three yeast RNA polymerases. Nucleic Acids Res 2006; 35:634-47. [PMID: 17179178 PMCID: PMC1802627 DOI: 10.1093/nar/gkl686] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 07/30/2006] [Accepted: 09/07/2006] [Indexed: 12/05/2022] Open
Abstract
Rpb5, a subunit shared by the three yeast RNA polymerases, combines a eukaryotic N-terminal module with a globular C-end conserved in all non-bacterial enzymes. Conditional and lethal mutants of the moderately conserved eukaryotic module showed that its large N-terminal helix and a short motif at the end of the module are critical in vivo. Lethal or conditional mutants of the C-terminal globe altered the binding of Rpb5 to Rpb1-beta25/26 (prolonging the Bridge helix) and Rpb1-alpha44/47 (ahead of the Switch 1 loop and binding Rpb5 in a two-hybrid assay). The large intervening segment of Rpb1 is held across the DNA Cleft by Rpb9, consistent with the synergy observed for rpb5 mutants and rpb9Delta or its RNA polymerase I rpa12Delta counterpart. Rpb1-beta25/26, Rpb1-alpha44/45 and the Switch 1 loop were only found in Rpb5-containing polymerases, but the Bridge and Rpb1-alpha46/47 helix bundle were universally conserved. We conclude that the main function of the dual Rpb5-Rpb1 binding and the Rpb9-Rpb1 interaction is to hold the Bridge helix, the Rpb1-alpha44/47 helix bundle and the Switch 1 loop into a closely packed DNA-binding fold around the transcription bubble, in an organization shared by the two other nuclear RNA polymerases and by the archaeal and viral enzymes.
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Affiliation(s)
- Cécile Zaros
- Service de Biochimie & Génétique Moléculaire.Bâtiment 144 CEA-Saclay, F-91191, Gif-sur-Yvette, CEDEX, France
| | - Jean-François Briand
- Service de Biochimie & Génétique Moléculaire.Bâtiment 144 CEA-Saclay, F-91191, Gif-sur-Yvette, CEDEX, France
| | - Yves Boulard
- Service de Biochimie & Génétique Moléculaire.Bâtiment 144 CEA-Saclay, F-91191, Gif-sur-Yvette, CEDEX, France
| | - Sylvie Labarre-Mariotte
- Service de Biochimie & Génétique Moléculaire.Bâtiment 144 CEA-Saclay, F-91191, Gif-sur-Yvette, CEDEX, France
| | - M. Carmen Garcia-Lopez
- Department Biología Experimental—Area de Genética (ED.B3) Universidad de Jaén Paraje lasLagunillas E-23071 Jaén, SPAIN
| | - Pierre Thuriaux
- Service de Biochimie & Génétique Moléculaire.Bâtiment 144 CEA-Saclay, F-91191, Gif-sur-Yvette, CEDEX, France
| | - Francisco Navarro
- Department Biología Experimental—Area de Genética (ED.B3) Universidad de Jaén Paraje lasLagunillas E-23071 Jaén, SPAIN
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Abstract
In eukaryotes, the core promoter serves as a platform for the assembly of transcription preinitiation complex (PIC) that includes TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIH, and RNA polymerase II (pol II), which function collectively to specify the transcription start site. PIC formation usually begins with TFIID binding to the TATA box, initiator, and/or downstream promoter element (DPE) found in most core promoters, followed by the entry of other general transcription factors (GTFs) and pol II through either a sequential assembly or a preassembled pol II holoenzyme pathway. Formation of this promoter-bound complex is sufficient for a basal level of transcription. However, for activator-dependent (or regulated) transcription, general cofactors are often required to transmit regulatory signals between gene-specific activators and the general transcription machinery. Three classes of general cofactors, including TBP-associated factors (TAFs), Mediator, and upstream stimulatory activity (USA)-derived positive cofactors (PC1/PARP-1, PC2, PC3/DNA topoisomerase I, and PC4) and negative cofactor 1 (NC1/HMGB1), normally function independently or in combination to fine-tune the promoter activity in a gene-specific or cell-type-specific manner. In addition, other cofactors, such as TAF1, BTAF1, and negative cofactor 2 (NC2), can also modulate TBP or TFIID binding to the core promoter. In general, these cofactors are capable of repressing basal transcription when activators are absent and stimulating transcription in the presence of activators. Here we review the roles of these cofactors and GTFs, as well as TBP-related factors (TRFs), TAF-containing complexes (TFTC, SAGA, SLIK/SALSA, STAGA, and PRC1) and TAF variants, in pol II-mediated transcription, with emphasis on the events occurring after the chromatin has been remodeled but prior to the formation of the first phosphodiester bond.
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Affiliation(s)
- Mary C Thomas
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH 44106-4935, USA
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40
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Fish RN, Ammerman ML, Davie JK, Lu BF, Pham C, Howe L, Ponticelli AS, Kane CM. Genetic interactions between TFIIF and TFIIS. Genetics 2006; 173:1871-84. [PMID: 16648643 PMCID: PMC1569716 DOI: 10.1534/genetics.106.058834] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2006] [Accepted: 04/28/2006] [Indexed: 11/18/2022] Open
Abstract
The eukaryotic transcript elongation factor TFIIS is encoded by a nonessential gene, PPR2, in Saccharomyces cerevisiae. Disruptions of PPR2 are lethal in conjunction with a disruption in the nonessential gene TAF14/TFG3. While investigating which of the Taf14p-containing complexes may be responsible for the synthetic lethality between ppr2Delta and taf14Delta, we discovered genetic interactions between PPR2 and both TFG1 and TFG2 encoding the two larger subunits of the TFIIF complex that also contains Taf14p. Mutant alleles of tfg1 or tfg2 that render cells cold sensitive have improved growth at low temperature in the absence of TFIIS. Remarkably, the amino-terminal 130 amino acids of TFIIS, which are dispensable for the known in vitro and in vivo activities of TFIIS, are required to complement the lethality in taf14Delta ppr2Delta cells. Analyses of deletion and chimeric gene constructs of PPR2 implicate contributions by different regions of this N-terminal domain. No strong common phenotypes were identified for the ppr2Delta and taf14Delta strains, implying that the proteins are not functionally redundant. Instead, the absence of Taf14p in the cell appears to create a dependence on an undefined function of TFIIS mediated by its N-terminal region. This region of TFIIS is also at least in part responsible for the deleterious effect of TFIIS on tfg1 or tfg2 cold-sensitive cells. Together, these results suggest a physiologically relevant functional connection between TFIIS and TFIIF.
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Affiliation(s)
- Rachel N Fish
- Department of Molecular and Cell Biology, University of California, Berkeley 94720-3202, USA
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41
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Miller G, Hahn S. A DNA-tethered cleavage probe reveals the path for promoter DNA in the yeast preinitiation complex. Nat Struct Mol Biol 2006; 13:603-10. [PMID: 16819517 PMCID: PMC2483788 DOI: 10.1038/nsmb1117] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Accepted: 06/02/2006] [Indexed: 11/08/2022]
Abstract
To directly map the position of promoter DNA within the RNA polymerase II (Pol II) transcription preinitiation complex (PIC), FeBABE was tethered to specific sites within the HIS4 promoter and used to map exposed surfaces of Pol II and the general transcription factors in proximity to DNA. Our results distinguish between previously proposed models for PIC structure and demonstrate that downstream promoter DNA is positioned over the central cleft of Pol II, with DNA upstream of TATA extending toward the Pol II subunit Rpb3. Also mapped were segments of TFIIB, TFIIE, TFIIF and TFIIH in proximity to promoter DNA. DNA downstream of the transcription bubble maps to a path between the two helicase subdomains of the TFIIH subunit Rad25 (also called XPB). Together, our results show how the general factors and Pol II converge on promoter DNA within the PIC.
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Affiliation(s)
- Gail Miller
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N., Seattle, Washington 98109, USA
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42
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Kuehner JN, Brow DA. Quantitative analysis of in vivo initiator selection by yeast RNA polymerase II supports a scanning model. J Biol Chem 2006; 281:14119-28. [PMID: 16571719 DOI: 10.1074/jbc.m601937200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Initiation of transcription by RNA polymerase II (RNAP II) on Saccharomyces cerevisiae messenger RNA (mRNA) genes typically occurs at multiple sites 40-120 bp downstream of the TATA box. The mechanism that accommodates this extended and variable promoter architecture is unknown, but one model suggests that RNAP II forms an open promoter complex near the TATA box and then scans the template DNA strand for start sites. Unlike most protein-coding genes, small nuclear RNA gene transcription starts predominantly at a single position. We identify a highly efficient initiator element as the primary start site determinant for the yeast U4 small nuclear RNA gene, SNR14. Consistent with the scanning model, transcription of an SNR14 allele with tandemly duplicated start sites initiates primarily from the upstream site, yet the downstream site is recognized with equivalent efficiency by the diminished population of RNAP II molecules that encounter it. A quantitative in vivo assay revealed that SNR14 initiator efficiency is nearly perfect (approximately 90%), which explains the precision of U4 RNA 5' end formation. Initiator efficiency was reduced by cis-acting mutations at -8, -7, -1, and +1 and trans-acting substitutions in the TFIIB B-finger. These results expand our understanding of RNAP II initiation preferences and provide new support for the scanning model.
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Affiliation(s)
- Jason N Kuehner
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
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43
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Freire-Picos MA, Krishnamurthy S, Sun ZW, Hampsey M. Evidence that the Tfg1/Tfg2 dimer interface of TFIIF lies near the active center of the RNA polymerase II initiation complex. Nucleic Acids Res 2005; 33:5045-52. [PMID: 16147988 PMCID: PMC1201334 DOI: 10.1093/nar/gki825] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Revised: 08/23/2005] [Accepted: 08/23/2005] [Indexed: 11/13/2022] Open
Abstract
The ssu71 alleles of the TFG1 gene, which encodes the largest subunit of TFIIF, were isolated as suppressors of a TFIIB defect that affects the accuracy of transcription start site selection in the yeast Saccharomyces cerevisiae. Here we report that ssu71-1 also suppresses the cell growth and start site defects associated with an altered form of the Rpb1 subunit of RNA polymerase II (RNAP II). The ssu71-1 and ssu71-2 alleles were cloned and found to encode single amino acid replacements of glycine-363, either glycine to aspartic acid (G363D) or glycine to arginine (G363R). Two other charged replacements, G363E and G363K, were constructed by site-directed mutagenesis and suppress both TFIIB E62K and Rpb1 N445S, whereas neither G363A nor G363P exhibited any effect. G363 is phylogenetically conserved and its counterpart in human TFIIF (RAP74 G112) is located within the RAP74/RAP30 dimerization domain. We propose that the TFIIF dimerization domain is located in proximity to the B-finger of TFIIB near the active center of RNAP II where the TFIIB-TFIIF-RNAP II interface plays a key role in start site selection.
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Affiliation(s)
- M. Angeles Freire-Picos
- Departamento de Bioloxía Celular e Molecular, Area de Bioquímica e Bioloxía MolecularCampus da Zapateira S/N 1071 A Coruña, Spain
- Department of Biochemistry, Division of Nucleic Acids Enzymology, UMDNJ-Robert Wood Johnson Medical SchoolPiscataway, NJ 08854, USA
| | - Shankarling Krishnamurthy
- Department of Biochemistry, Division of Nucleic Acids Enzymology, UMDNJ-Robert Wood Johnson Medical SchoolPiscataway, NJ 08854, USA
| | - Zu-Wen Sun
- Department of Biochemistry, Division of Nucleic Acids Enzymology, UMDNJ-Robert Wood Johnson Medical SchoolPiscataway, NJ 08854, USA
| | - Michael Hampsey
- Department of Biochemistry, Division of Nucleic Acids Enzymology, UMDNJ-Robert Wood Johnson Medical SchoolPiscataway, NJ 08854, USA
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Majovski RC, Khaperskyy DA, Ghazy MA, Ponticelli AS. A functional role for the switch 2 region of yeast RNA polymerase II in transcription start site utilization and abortive initiation. J Biol Chem 2005; 280:34917-23. [PMID: 16081422 DOI: 10.1074/jbc.m502932200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RNA polymerase II (RNAPII) is responsible for the synthesis of mRNA from eukaryotic protein-encoding genes. In this study, site-directed mutagenesis was employed to probe the function of residues within the Saccharomyces cerevisiae RNAPII active center in the mechanism of transcription start site utilization. We report here the identification of two mutations in the switch 2 region, rpb1-K332A and rpb1-R344A, which conferred conditional growth properties and downstream shifts in start site utilization. Analyses of double mutant strains demonstrated functional interactions between these switch 2 mutations and a mutation in the largest subunit of transcription factor IIF (TFIIF) that confers upstream shifts in start site usage. Importantly, biochemical analyses demonstrated that purified Rpb1-R344A mutant polymerase exhibited impaired ability to stabilize a short RNA-DNA hybrid in the active center, an increased frequency of abortive transcription in runoff assays, and both a downstream shift and increased abortive initiation in reconstituted transcription assays. These results provide evidence for a role of switch 2 during start site utilization and indicate that RNA-DNA hybrid stability at the 3'-end of the transcript is a determinant in this process. We discuss these results within the context of a proposed model regarding the concerted roles of RNAPII, TFIIB, and TFIIF during mRNA 5'-end formation in S. cerevisiae.
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Affiliation(s)
- Robert C Majovski
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York, Buffalo, New York 14214-3000, USA
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45
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Current awareness on yeast. Yeast 2005; 22:745-52. [PMID: 16106592 DOI: 10.1002/yea.1165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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