1
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Chen Y, Cramer P. RNA polymerase II elongation factors use conserved regulatory mechanisms. Curr Opin Struct Biol 2024; 84:102766. [PMID: 38181687 DOI: 10.1016/j.sbi.2023.102766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/11/2023] [Accepted: 12/13/2023] [Indexed: 01/07/2024]
Abstract
RNA polymerase II (Pol II) transcription is regulated by many elongation factors. Among these factors, TFIIF, PAF-RTF1, ELL and Elongin stimulate mRNA chain elongation by Pol II. Cryo-EM structures of Pol II complexes with these elongation factors now reveal some general principles on how elongation factors bind Pol II and how they stimulate transcription. All four elongation factors contact Pol II at domains external 2 and protrusion, whereas TFIIF and ELL additionally bind the Pol II lobe. All factors apparently stabilize cleft-flanking elements, whereas RTF1 and Elongin additionally approach the active site with a latch element and may influence catalysis or translocation. Due to the shared binding sites on Pol II, factor binding is mutually exclusive, and thus it remains to be studied what determines which elongation factors bind at a certain gene and under which condition.
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Affiliation(s)
- Ying Chen
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany.
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany.
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2
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Pal S, Biswas D. Promoter-proximal regulation of gene transcription: Key factors involved and emerging role of general transcription factors in assisting productive elongation. Gene 2023:147571. [PMID: 37331491 DOI: 10.1016/j.gene.2023.147571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/02/2023] [Accepted: 06/13/2023] [Indexed: 06/20/2023]
Abstract
The pausing of RNA polymerase II (Pol II) at the promoter-proximal sites is a key rate-limiting step in gene expression. Cells have dedicated a specific set of proteins that sequentially establish pause and then release the Pol II from promoter-proximal sites. A well-controlled pausing and subsequent release of Pol II is crucial for thefine tuning of expression of genes including signal-responsive and developmentally-regulated ones. The release of paused Pol II broadly involves its transition from initiation to elongation. In this review article, we will discuss the phenomenon of Pol II pausing, the underlying mechanism, and also the role of different known factors, with an emphasis on general transcription factors, involved in this overall regulation. We will further discuss some recent findings suggesting a possible role (underexplored) of initiation factors in assisting the transition of transcriptionally-engaged paused Pol II into productive elongation.
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Affiliation(s)
- Sujay Pal
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata - 32, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Debabrata Biswas
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata - 32, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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3
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Duval M, Yague-Sanz C, Turowski TW, Petfalski E, Tollervey D, Bachand F. The conserved RNA-binding protein Seb1 promotes cotranscriptional ribosomal RNA processing by controlling RNA polymerase I progression. Nat Commun 2023; 14:3013. [PMID: 37230993 DOI: 10.1038/s41467-023-38826-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 05/16/2023] [Indexed: 05/27/2023] Open
Abstract
Transcription by RNA polymerase I (RNAPI) represents most of the transcriptional activity in eukaryotic cells and is associated with the production of mature ribosomal RNA (rRNA). As several rRNA maturation steps are coupled to RNAPI transcription, the rate of RNAPI elongation directly influences processing of nascent pre-rRNA, and changes in RNAPI transcription rate can result in alternative rRNA processing pathways in response to growth conditions and stress. However, factors and mechanisms that control RNAPI progression by influencing transcription elongation rate remain poorly understood. We show here that the conserved fission yeast RNA-binding protein Seb1 associates with the RNAPI transcription machinery and promotes RNAPI pausing states along the rDNA. The overall faster progression of RNAPI at the rDNA in Seb1-deficient cells impaired cotranscriptional pre-rRNA processing and the production of mature rRNAs. Given that Seb1 also influences pre-mRNA processing by modulating RNAPII progression, our findings unveil Seb1 as a pause-promoting factor for RNA polymerases I and II to control cotranscriptional RNA processing.
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Affiliation(s)
- Maxime Duval
- RNA group, Department of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Carlo Yague-Sanz
- RNA group, Department of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC, Canada
- URPHYM-GEMO, The University of Namur, 5000, Namur, Belgium
| | - Tomasz W Turowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | | | - David Tollervey
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - François Bachand
- RNA group, Department of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC, Canada.
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4
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Wee LM, Tong AB, Florez Ariza AJ, Cañari-Chumpitaz C, Grob P, Nogales E, Bustamante CJ. A trailing ribosome speeds up RNA polymerase at the expense of transcript fidelity via force and allostery. Cell 2023; 186:1244-1262.e34. [PMID: 36931247 PMCID: PMC10135430 DOI: 10.1016/j.cell.2023.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 11/14/2022] [Accepted: 02/06/2023] [Indexed: 03/18/2023]
Abstract
In prokaryotes, translation can occur on mRNA that is being transcribed in a process called coupling. How the ribosome affects the RNA polymerase (RNAP) during coupling is not well understood. Here, we reconstituted the E. coli coupling system and demonstrated that the ribosome can prevent pausing and termination of RNAP and double the overall transcription rate at the expense of fidelity. Moreover, we monitored single RNAPs coupled to ribosomes and show that coupling increases the pause-free velocity of the polymerase and that a mechanical assisting force is sufficient to explain the majority of the effects of coupling. Also, by cryo-EM, we observed that RNAPs with a terminal mismatch adopt a backtracked conformation, while a coupled ribosome allosterically induces these polymerases toward a catalytically active anti-swiveled state. Finally, we demonstrate that prolonged RNAP pausing is detrimental to cell viability, which could be prevented by polymerase reactivation through a coupled ribosome.
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Affiliation(s)
- Liang Meng Wee
- QB3-Berkeley, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA
| | - Alexander B Tong
- QB3-Berkeley, Berkeley, CA, USA; Department of Chemistry, University of California Berkeley, Berkeley, CA, USA
| | - Alfredo Jose Florez Ariza
- QB3-Berkeley, Berkeley, CA, USA; Biophysics Graduate Group, University of California Berkeley, Berkeley, CA, USA
| | - Cristhian Cañari-Chumpitaz
- QB3-Berkeley, Berkeley, CA, USA; Department of Chemistry, University of California Berkeley, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA
| | - Patricia Grob
- QB3-Berkeley, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA; Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
| | - Eva Nogales
- QB3-Berkeley, Berkeley, CA, USA; Biophysics Graduate Group, University of California Berkeley, Berkeley, CA, USA; Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Carlos J Bustamante
- QB3-Berkeley, Berkeley, CA, USA; Biophysics Graduate Group, University of California Berkeley, Berkeley, CA, USA; Department of Chemistry, University of California Berkeley, Berkeley, CA, USA; Department of Physics, University of California Berkeley, Berkeley, CA, USA; Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA; Kavli Energy Nanoscience Institute, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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5
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Obermeyer S, Stöckl R, Schnekenburger T, Kapoor H, Stempfl T, Schwartz U, Grasser KD. TFIIS Is Crucial During Early Transcript Elongation for Transcriptional Reprogramming in Response to Heat Stress. J Mol Biol 2023; 435:167917. [PMID: 36502880 DOI: 10.1016/j.jmb.2022.167917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/01/2022] [Accepted: 12/04/2022] [Indexed: 12/13/2022]
Abstract
In addition to the stage of transcriptional initiation, the production of mRNAs is regulated during elongation. Accordingly, the synthesis of mRNAs by RNA polymerase II (RNAPII) in the chromatin context is modulated by various transcript elongation factors. TFIIS is an elongation factor that stimulates the transcript cleavage activity of RNAPII to reactivate stalled elongation complexes at barriers to transcription including nucleosomes. Since Arabidopsis tfIIs mutants grow normally under standard conditions, we have exposed them to heat stress (HS), revealing that tfIIs plants are highly sensitive to elevated temperatures. Transcriptomic analyses demonstrate that particularly HS-induced genes are expressed at lower levels in tfIIs than in wildtype. Mapping the distribution of elongating RNAPII uncovered that in tfIIs plants RNAPII accumulates at the +1 nucleosome of genes that are upregulated upon HS. The promoter-proximal RNAPII accumulation in tfIIs under HS conditions conforms to that observed upon inhibition of the RNAPII transcript cleavage activity. Further analysis of the RNAPII accumulation downstream of transcriptional start sites illustrated that RNAPII stalling occurs at +1 nucleosomes that are depleted in the histone variant H2A.Z upon HS. Therefore, assistance of early transcript elongation by TFIIS is required for reprogramming gene expression to establish plant thermotolerance.
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Affiliation(s)
- Simon Obermeyer
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Richard Stöckl
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Tobias Schnekenburger
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Henna Kapoor
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Thomas Stempfl
- Center of Excellence for Fluorescent Bioanalytics (KFB), University of Regensburg, Am Biopark 9, D-93053 Regensburg, Germany
| | - Uwe Schwartz
- NGS Analysis Centre, Biology and Pre-Clinical Medicine, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Klaus D Grasser
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany.
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6
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Wu X, Xie Y, Zhao K, Lu J. Targeting the super elongation complex for oncogenic transcription driven tumor malignancies: Progress in structure, mechanisms and small molecular inhibitor discovery. Adv Cancer Res 2023; 158:387-421. [PMID: 36990537 DOI: 10.1016/bs.acr.2022.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Oncogenic transcription activation is associated with tumor development and resistance derived from chemotherapy or target therapy. The super elongation complex (SEC) is an important complex regulating gene transcription and expression in metazoans closely related to physiological activities. In normal transcriptional regulation, SEC can trigger promoter escape, limit proteolytic degradation of transcription elongation factors and increase the synthesis of RNA polymerase II (POL II), and regulate many normal human genes to stimulate RNA elongation. Dysregulation of SEC accompanied by multiple transcription factors in cancer promotes rapid transcription of oncogenes and induce cancer development. In this review, we summarized recent progress in understanding the mechanisms of SEC in regulating normal transcription, and importantly its roles in cancer development. We also highlighted the discovery of SEC complex target related inhibitors and their potential applications in cancer treatment.
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Affiliation(s)
- Xinyu Wu
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China; Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yanqiu Xie
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China; Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Kehao Zhao
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China.
| | - Jing Lu
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China.
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7
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Kor R, Mohammad-Rafiee F. Theoretical study of RNA-polymerase behavior considering the backtracking state. SOFT MATTER 2022; 18:5979-5988. [PMID: 35920142 DOI: 10.1039/d2sm00232a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The dynamical behavior of the RNA polymerase in the transcription process is vital to gene expression. During the transcription process, the 3' end of the transcribed RNA can be dislocated from the active site of the enzyme and as a result, the RNA polymerase goes to the backtracked state. Here, we develop a theoretical model to study the transcription process considering the backtracking state. We aim at describing the behavior of the enzyme in the backtracking state in the presence of an external force, which leads to two possibilities: (i) rescuing from the backtracking state and, (ii) the arresting of the enzyme. We study the probability and the rate of the mentioned processes. In addition, we find that entering the backtracking state behaves like the Brownian ratchet mechanism. This model could shed some light on the modeling of the transcription process and further studies on the energy landscape of the backtracking channel and the gene regulation.
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Affiliation(s)
- Razieh Kor
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.
| | - Farshid Mohammad-Rafiee
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.
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8
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Appel LM, Franke V, Bruno M, Grishkovskaya I, Kasiliauskaite A, Kaufmann T, Schoeberl UE, Puchinger MG, Kostrhon S, Ebenwaldner C, Sebesta M, Beltzung E, Mechtler K, Lin G, Vlasova A, Leeb M, Pavri R, Stark A, Akalin A, Stefl R, Bernecky C, Djinovic-Carugo K, Slade D. PHF3 regulates neuronal gene expression through the Pol II CTD reader domain SPOC. Nat Commun 2021; 12:6078. [PMID: 34667177 PMCID: PMC8526623 DOI: 10.1038/s41467-021-26360-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 09/29/2021] [Indexed: 12/16/2022] Open
Abstract
The C-terminal domain (CTD) of the largest subunit of RNA polymerase II (Pol II) is a regulatory hub for transcription and RNA processing. Here, we identify PHD-finger protein 3 (PHF3) as a regulator of transcription and mRNA stability that docks onto Pol II CTD through its SPOC domain. We characterize SPOC as a CTD reader domain that preferentially binds two phosphorylated Serine-2 marks in adjacent CTD repeats. PHF3 drives liquid-liquid phase separation of phosphorylated Pol II, colocalizes with Pol II clusters and tracks with Pol II across the length of genes. PHF3 knock-out or SPOC deletion in human cells results in increased Pol II stalling, reduced elongation rate and an increase in mRNA stability, with marked derepression of neuronal genes. Key neuronal genes are aberrantly expressed in Phf3 knock-out mouse embryonic stem cells, resulting in impaired neuronal differentiation. Our data suggest that PHF3 acts as a prominent effector of neuronal gene regulation by bridging transcription with mRNA decay.
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Affiliation(s)
- Lisa-Marie Appel
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Vedran Franke
- The Berlin Institute for Medical Systems Biology, Max Delbrück Center, Berlin, Germany
| | - Melania Bruno
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Irina Grishkovskaya
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Aiste Kasiliauskaite
- CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Tanja Kaufmann
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Ursula E Schoeberl
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Martin G Puchinger
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Sebastian Kostrhon
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Carmen Ebenwaldner
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Marek Sebesta
- CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Etienne Beltzung
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Karl Mechtler
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, Vienna Biocenter (VBC), Vienna, Austria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - Gen Lin
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, Vienna Biocenter (VBC), Vienna, Austria
| | - Anna Vlasova
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, Vienna Biocenter (VBC), Vienna, Austria
| | - Martin Leeb
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Rushad Pavri
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, Vienna Biocenter (VBC), Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, Vienna Biocenter (VBC), Vienna, Austria
| | - Altuna Akalin
- The Berlin Institute for Medical Systems Biology, Max Delbrück Center, Berlin, Germany
| | - Richard Stefl
- CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Carrie Bernecky
- Institute of Science and Technology Austria (IST Austria), Am Campus 1, Klosterneuburg, Austria
| | - Kristina Djinovic-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Dea Slade
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria.
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.
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9
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Muniz L, Nicolas E, Trouche D. RNA polymerase II speed: a key player in controlling and adapting transcriptome composition. EMBO J 2021; 40:e105740. [PMID: 34254686 PMCID: PMC8327950 DOI: 10.15252/embj.2020105740] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 05/01/2021] [Accepted: 05/10/2021] [Indexed: 12/19/2022] Open
Abstract
RNA polymerase II (RNA Pol II) speed or elongation rate, i.e., the number of nucleotides synthesized per unit of time, is a major determinant of transcriptome composition. It controls co-transcriptional processes such as splicing, polyadenylation, and transcription termination, thus regulating the production of alternative splice variants, circular RNAs, alternatively polyadenylated transcripts, or read-through transcripts. RNA Pol II speed itself is regulated in response to intra- and extra-cellular stimuli and can in turn affect the transcriptome composition in response to these stimuli. Evidence points to a potentially important role of transcriptome composition modification through RNA Pol II speed regulation for adaptation of cells to a changing environment, thus pointing to a function of RNA Pol II speed regulation in cellular physiology. Analyzing RNA Pol II speed dynamics may therefore be central to fully understand the regulation of physiological processes, such as the development of multicellular organisms. Recent findings also raise the possibility that RNA Pol II speed deregulation can be detrimental and participate in disease progression. Here, we review initial and current approaches to measure RNA Pol II speed, as well as providing an overview of the factors controlling speed and the co-transcriptional processes which are affected. Finally, we discuss the role of RNA Pol II speed regulation in cell physiology.
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Affiliation(s)
- Lisa Muniz
- MCDCentre de Biologie Integrative (CBI)CNRSUPSUniversity of ToulouseToulouseFrance
| | - Estelle Nicolas
- MCDCentre de Biologie Integrative (CBI)CNRSUPSUniversity of ToulouseToulouseFrance
| | - Didier Trouche
- MCDCentre de Biologie Integrative (CBI)CNRSUPSUniversity of ToulouseToulouseFrance
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10
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Chanou A, Hamperl S. Single-Molecule Techniques to Study Chromatin. Front Cell Dev Biol 2021; 9:699771. [PMID: 34291054 PMCID: PMC8287188 DOI: 10.3389/fcell.2021.699771] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 05/26/2021] [Indexed: 12/14/2022] Open
Abstract
Besides the basic organization in nucleosome core particles (NCPs), eukaryotic chromatin is further packed through interactions with numerous protein complexes including transcription factors, chromatin remodeling and modifying enzymes. This nucleoprotein complex provides the template for many important biological processes, such as DNA replication, transcription, and DNA repair. Thus, to understand the molecular basis of these DNA transactions, it is critical to define individual changes of the chromatin structure at precise genomic regions where these machineries assemble and drive biological reactions. Single-molecule approaches provide the only possible solution to overcome the heterogenous nature of chromatin and monitor the behavior of individual chromatin transactions in real-time. In this review, we will give an overview of currently available single-molecule methods to obtain mechanistic insights into nucleosome positioning, histone modifications and DNA replication and transcription analysis-previously unattainable with population-based assays.
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Affiliation(s)
| | - Stephan Hamperl
- Chromosome Dynamics and Genome Stability, Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
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11
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Noe Gonzalez M, Blears D, Svejstrup JQ. Causes and consequences of RNA polymerase II stalling during transcript elongation. Nat Rev Mol Cell Biol 2021; 22:3-21. [PMID: 33208928 DOI: 10.1038/s41580-020-00308-8] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2020] [Indexed: 02/07/2023]
Abstract
The journey of RNA polymerase II (Pol II) as it transcribes a gene is anything but a smooth ride. Transcript elongation is discontinuous and can be perturbed by intrinsic regulatory barriers, such as promoter-proximal pausing, nucleosomes, RNA secondary structures and the underlying DNA sequence. More substantial blocking of Pol II translocation can be caused by other physiological circumstances and extrinsic obstacles, including other transcribing polymerases, the replication machinery and several types of DNA damage, such as bulky lesions and DNA double-strand breaks. Although numerous different obstacles cause Pol II stalling or arrest, the cell somehow distinguishes between them and invokes different mechanisms to resolve each roadblock. Resolution of Pol II blocking can be as straightforward as temporary backtracking and transcription elongation factor S-II (TFIIS)-dependent RNA cleavage, or as drastic as premature transcription termination or degradation of polyubiquitylated Pol II and its associated nascent RNA. In this Review, we discuss the current knowledge of how these different Pol II stalling contexts are distinguished by the cell, how they overlap with each other, how they are resolved and how, when unresolved, they can cause genome instability.
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Affiliation(s)
- Melvin Noe Gonzalez
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Daniel Blears
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Q Svejstrup
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK.
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
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12
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Oh J, Xu J, Chong J, Wang D. Molecular basis of transcriptional pausing, stalling, and transcription-coupled repair initiation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194659. [PMID: 33271312 DOI: 10.1016/j.bbagrm.2020.194659] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/21/2020] [Accepted: 11/23/2020] [Indexed: 12/24/2022]
Abstract
Transcription elongation by RNA polymerase II (Pol II) is constantly challenged by numerous types of obstacles that lead to transcriptional pausing or stalling. These obstacles include DNA lesions, DNA epigenetic modifications, DNA binding proteins, and non-B form DNA structures. In particular, lesion-induced prolonged transcriptional blockage or stalling leads to genome instability, cellular dysfunction, and cell death. Transcription-coupled nucleotide excision repair (TC-NER) pathway is the first line of defense that detects and repairs these transcription-blocking DNA lesions. In this review, we will first summarize the recent research progress toward understanding the molecular basis of transcriptional pausing and stalling by different kinds of obstacles. We will then discuss new insights into Pol II-mediated lesion recognition and the roles of CSB in TC-NER.
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Affiliation(s)
- Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, United States
| | - Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, United States
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, United States
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, United States; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, United States; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, United States.
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13
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Xu J, Wang W, Xu L, Chen JY, Chong J, Oh J, Leschziner AE, Fu XD, Wang D. Cockayne syndrome B protein acts as an ATP-dependent processivity factor that helps RNA polymerase II overcome nucleosome barriers. Proc Natl Acad Sci U S A 2020; 117:25486-25493. [PMID: 32989164 PMCID: PMC7568279 DOI: 10.1073/pnas.2013379117] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
While loss-of-function mutations in Cockayne syndrome group B protein (CSB) cause neurological diseases, this unique member of the SWI2/SNF2 family of chromatin remodelers has been broadly implicated in transcription elongation and transcription-coupled DNA damage repair, yet its mechanism remains largely elusive. Here, we use a reconstituted in vitro transcription system with purified polymerase II (Pol II) and Rad26, a yeast ortholog of CSB, to study the role of CSB in transcription elongation through nucleosome barriers. We show that CSB forms a stable complex with Pol II and acts as an ATP-dependent processivity factor that helps Pol II across a nucleosome barrier. This noncanonical mechanism is distinct from the canonical modes of chromatin remodelers that directly engage and remodel nucleosomes or transcription elongation factors that facilitate Pol II nucleosome bypass without hydrolyzing ATP. We propose a model where CSB facilitates gene expression by helping Pol II bypass chromatin obstacles while maintaining their structures.
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Affiliation(s)
- Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Wei Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Liang Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Jia-Yu Chen
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Andres E Leschziner
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093
- Section of Molecular Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093;
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093
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14
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Hafner A, Reyes J, Stewart-Ornstein J, Tsabar M, Jambhekar A, Lahav G. Quantifying the Central Dogma in the p53 Pathway in Live Single Cells. Cell Syst 2020; 10:495-505.e4. [PMID: 32533938 DOI: 10.1016/j.cels.2020.05.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 03/08/2020] [Accepted: 05/06/2020] [Indexed: 10/24/2022]
Abstract
Transcription factors (TFs) integrate signals to regulate target gene expression, but we generally lack a quantitative understanding of how changes in TF levels regulate mRNA and protein production. Here, we established a system to simultaneously monitor the levels of p53, a TF that shows oscillations following DNA damage, and the transcription and protein levels of its target p21 in individual cells. p21 transcription tracked p53 dynamics, while p21 protein steadily accumulated. p21 transcriptional activation showed bursts of mRNA production, with p53 levels regulating the probability but not magnitude of activation. Variations in p53 levels between cells contributed to heterogeneous p21 transcription while independent p21 alleles exhibited highly correlated behaviors. Pharmacologically elevating p53 increased the probability of p21 transcription with minor effects on its magnitude, leading to a strong increase in p21 protein levels. Our results reveal quantitative mechanisms by which TF dynamics can regulate protein levels of its targets. A record of this paper's transparent peer review process is included in the Supplemental Information.
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Affiliation(s)
- Antonina Hafner
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - José Reyes
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | | | - Michael Tsabar
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Laboratory of Systems Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Ashwini Jambhekar
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Galit Lahav
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
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15
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Antosz W, Deforges J, Begcy K, Bruckmann A, Poirier Y, Dresselhaus T, Grasser KD. Critical Role of Transcript Cleavage in Arabidopsis RNA Polymerase II Transcriptional Elongation. THE PLANT CELL 2020; 32:1449-1463. [PMID: 32152189 PMCID: PMC7203918 DOI: 10.1105/tpc.19.00891] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/10/2020] [Accepted: 03/05/2020] [Indexed: 05/14/2023]
Abstract
Transcript elongation factors associate with elongating RNA polymerase II (RNAPII) to control the efficiency of mRNA synthesis and consequently modulate plant growth and development. Encountering obstacles during transcription such as nucleosomes or particular DNA sequences may cause backtracking and transcriptional arrest of RNAPII. The elongation factor TFIIS stimulates the intrinsic transcript cleavage activity of the polymerase, which is required for efficient rescue of backtracked/arrested RNAPII. A TFIIS mutant variant (TFIISmut) lacks the stimulatory activity to promote RNA cleavage, but instead efficiently inhibits unstimulated transcript cleavage by RNAPII. We could not recover viable Arabidopsis (Arabidopsis thaliana) tfIIs plants constitutively expressing TFIISmut. Induced, transient expression of TFIISmut in tfIIs plants provoked severe growth defects, transcriptomic changes and massive, transcription-related redistribution of elongating RNAPII within transcribed regions toward the transcriptional start site. The predominant site of RNAPII accumulation overlapped with the +1 nucleosome, suggesting that upon inhibition of RNA cleavage activity, RNAPII arrest prevalently occurs at this position. In the presence of TFIISmut, the amount of RNAPII was reduced, which could be reverted by inhibiting the proteasome, indicating proteasomal degradation of arrested RNAPII. Our findings suggest that polymerase backtracking/arrest frequently occurs in plant cells, and RNAPII-reactivation is essential for correct transcriptional output and proper growth/development.
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Affiliation(s)
- Wojciech Antosz
- Department of Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93040 Regensburg, Germany
| | - Jules Deforges
- Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Kevin Begcy
- Environmental Horticulture Department, University of Florida, Gainesville, Florida 32611
| | - Astrid Bruckmann
- Department for Biochemistry I, Biochemistry Centre, University of Regensburg, D-93040 Regensburg, Germany
| | - Yves Poirier
- Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Thomas Dresselhaus
- Department of Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93040 Regensburg, Germany
| | - Klaus D Grasser
- Department of Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93040 Regensburg, Germany
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16
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Chen FX, Smith ER, Shilatifard A. Born to run: control of transcription elongation by RNA polymerase II. Nat Rev Mol Cell Biol 2019; 19:464-478. [PMID: 29740129 DOI: 10.1038/s41580-018-0010-5] [Citation(s) in RCA: 253] [Impact Index Per Article: 50.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The dynamic regulation of transcription elongation by RNA polymerase II (Pol II) is an integral part of the implementation of gene expression programmes during development. In most metazoans, the majority of transcribed genes exhibit transient pausing of Pol II at promoter-proximal regions, and the release of Pol II into gene bodies is controlled by many regulatory factors that respond to environmental and developmental cues. Misregulation of the elongation stage of transcription is implicated in cancer and other human diseases, suggesting that mechanistic understanding of transcription elongation control is therapeutically relevant. In this Review, we discuss the features, establishment and maintenance of Pol II pausing, the transition into productive elongation, the control of transcription elongation by enhancers and by factors of other cellular processes, such as topoisomerases and poly(ADP-ribose) polymerases (PARPs), and the potential of therapeutic targeting of the elongation stage of transcription by Pol II.
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Affiliation(s)
- Fei Xavier Chen
- Simpson Querrey Center for Epigenetics and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Edwin R Smith
- Simpson Querrey Center for Epigenetics and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Ali Shilatifard
- Simpson Querrey Center for Epigenetics and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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17
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Lee J, Crickard JB, Reese JC, Lee TH. Single-molecule FRET method to investigate the dynamics of transcription elongation through the nucleosome by RNA polymerase II. Methods 2019; 159-160:51-58. [PMID: 30660864 PMCID: PMC6589119 DOI: 10.1016/j.ymeth.2019.01.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/07/2019] [Accepted: 01/14/2019] [Indexed: 12/27/2022] Open
Abstract
Transcription elongation through the nucleosome is a precisely coordinated activity to ensure timely production of RNA and accurate regulation of co-transcriptional histone modifications. Nucleosomes actively participate in transcription regulation at various levels and impose physical barriers to RNA polymerase II (RNAPII) during transcription elongation. Despite its high significance, the detailed dynamics of how RNAPII translocates along nucleosomal DNA during transcription elongation and how the nucleosome structure dynamically conforms to the changes necessary for RNAPII progression remain poorly understood. Transcription elongation through the nucleosome is a complex process and investigating the changes of the nucleosome structure during this process by ensemble measurements is daunting. This is because it is nearly impossible to synchronize elongation complexes within a nucleosome or a sub-nucleosome to a designated location at a high enough efficiency for desired sample homogeneity. Here we review our recently developed single-molecule FRET experimental system and method that has fulfilled this deficiency. With our method, one can follow the changes in the structure of individual nucleosomes during transcription elongation. We demonstrated that this method enables the detailed measurements of the kinetics of transcription elongation through the nucleosome and its regulation by a transcription factor, which can be easily extended to investigations of the roles of environmental variables and histone post-translational modifications in regulating transcription elongation.
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Affiliation(s)
- Jaehyoun Lee
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
| | - J Brooks Crickard
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, United States
| | - Joseph C Reese
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, United States
| | - Tae-Hee Lee
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States.
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18
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Sanders TJ, Lammers M, Marshall CJ, Walker JE, Lynch ER, Santangelo TJ. TFS and Spt4/5 accelerate transcription through archaeal histone-based chromatin. Mol Microbiol 2019; 111:784-797. [PMID: 30592095 PMCID: PMC6417941 DOI: 10.1111/mmi.14191] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2018] [Indexed: 12/25/2022]
Abstract
RNA polymerase must surmount translocation barriers for continued transcription. In Eukarya and most Archaea, DNA-bound histone proteins represent the most common and troublesome barrier to transcription elongation. Eukaryotes encode a plethora of chromatin-remodeling complexes, histone-modification enzymes and transcription elongation factors to aid transcription through nucleosomes, while archaea seemingly lack machinery to remodel/modify histone-based chromatin and thus must rely on elongation factors to accelerate transcription through chromatin-barriers. TFS (TFIIS in Eukarya) and the Spt4-Spt5 complex are universally encoded in archaeal genomes, and here we demonstrate that both elongation factors, via different mechanisms, can accelerate transcription through archaeal histone-based chromatin. Histone proteins in Thermococcus kodakarensis are sufficiently abundant to completely wrap all genomic DNA, resulting in a consistent protein barrier to transcription elongation. TFS-enhanced cleavage of RNAs in backtracked transcription complexes reactivates stalled RNAPs and dramatically accelerates transcription through histone-barriers, while Spt4-Spt5 changes to clamp-domain dynamics play a lesser-role in stabilizing transcription. Repeated attempts to delete TFS, Spt4 and Spt5 from the T. kodakarensis genome were not successful, and the essentiality of both conserved transcription elongation factors suggests that both conserved elongation factors play important roles in transcription regulation in vivo, including mechanisms to accelerate transcription through downstream protein barriers.
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Affiliation(s)
- Travis J. Sanders
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Marshall Lammers
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Craig J. Marshall
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Julie E. Walker
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, 80523, USA
- Current address: Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado, 80303, USA
| | - Erin R. Lynch
- Graduate Program in Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Thomas J. Santangelo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, 80523, USA
- Graduate Program in Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado, 80523, USA
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19
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Widespread Backtracking by RNA Pol II Is a Major Effector of Gene Activation, 5' Pause Release, Termination, and Transcription Elongation Rate. Mol Cell 2018; 73:107-118.e4. [PMID: 30503775 DOI: 10.1016/j.molcel.2018.10.031] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 08/10/2018] [Accepted: 10/17/2018] [Indexed: 10/27/2022]
Abstract
In addition to phosphodiester bond formation, RNA polymerase II has an RNA endonuclease activity, stimulated by TFIIS, which rescues complexes that have arrested and backtracked. How TFIIS affects transcription under normal conditions is poorly understood. We identified backtracking sites in human cells using a dominant-negative TFIIS (TFIISDN) that inhibits RNA cleavage and stabilizes backtracked complexes. Backtracking is most frequent within 2 kb of start sites, consistent with slow elongation early in transcription, and in 3' flanking regions where termination is enhanced by TFIISDN, suggesting that backtracked pol II is a favorable substrate for termination. Rescue from backtracking by RNA cleavage also promotes escape from 5' pause sites, prevents premature termination of long transcripts, and enhances activation of stress-inducible genes. TFIISDN slowed elongation rates genome-wide by half, suggesting that rescue of backtracked pol II by TFIIS is a major stimulus of elongation under normal conditions.
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20
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Yu H, Xue C, Long M, Jia H, Xue G, Du S, Coello Y, Ishibashi T. TEFM Enhances Transcription Elongation by Modifying mtRNAP Pausing Dynamics. Biophys J 2018; 115:2295-2300. [PMID: 30514634 DOI: 10.1016/j.bpj.2018.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/25/2018] [Accepted: 11/05/2018] [Indexed: 10/27/2022] Open
Abstract
Regulation of transcription elongation is one of the key mechanisms employed to control gene expression. The single-subunit mitochondrial RNA polymerase (mtRNAP) transcribes mitochondrial genes, such as those related to ATP synthesis. We investigated how mitochondrial transcription elongation factor (TEFM) enhances mtRNAP transcription elongation using a single-molecule optical-tweezers transcription assay, which follows transcription dynamics in real time and allows the separation of pause-free elongation from transcriptional pauses. We found that TEFM enhances the stall force of mtRNAP. Although TEFM does not change the pause-free elongation rate, it enhances mtRNAP transcription elongation by reducing the frequency of long-lived pauses and shortening their durations. Furthermore, we demonstrate how mtRNAP passes through the conserved sequence block II, which is the key sequence for the switch between DNA replication and transcription in mitochondria. Our findings elucidate how both TEFM and mitochondrial genomic DNA sequences directly control the transcription elongation dynamics of mtRNAP.
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Affiliation(s)
- Hongwu Yu
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Cheng Xue
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Mengping Long
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Huiqiang Jia
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Guosheng Xue
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China; Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Shengwang Du
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China; Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Yves Coello
- Departamento de Ciencias, Sección Química, Pontificia Universidad Católica del Perú PUCP, Lima, Peru
| | - Toyotaka Ishibashi
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China.
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21
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Court F, Arnaud P. An annotated list of bivalent chromatin regions in human ES cells: a new tool for cancer epigenetic research. Oncotarget 2018; 8:4110-4124. [PMID: 27926531 PMCID: PMC5354816 DOI: 10.18632/oncotarget.13746] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/23/2016] [Indexed: 12/12/2022] Open
Abstract
CpG islands (CGI) marked by bivalent chromatin in stem cells are believed to be more prone to aberrant DNA methylation in tumor cells. The robustness and genome-wide extent of this instructive program in different cancer types remain to be determined. To address this issue we developed a user-friendly approach to integrate the stem cell chromatin signature in customized DNA methylation analyses. We used publicly available ChIP-sequencing datasets of several human embryonic stem cell (hESC) lines to determine the extent of bivalent chromatin genome-wide. We then created annotated lists of high-confidence bivalent, H3K4me3-only and H3K27me3-only chromatin regions. The main features of bivalent regions included localization in CGI/promoters, depletion in retroelements and enrichment in specific histone modifications, including the poorly characterized H3K23me2 mark. Moreover, bivalent promoters could be classified in three clusters based on PRC2 and PolII complexes occupancy. Genes with bivalent promoters of the PRC2-defined cluster displayed the lowest expression upon differentiation. As proof-of-concept, we assessed the DNA methylation pattern of eight types of tumors and confirmed that aberrant cancer-associated DNA hypermethylation preferentially targets CGI characterized by bivalent chromatin in hESCs. We also found that such aberrant DNA hypermethylation affected particularly bivalent CGI/promoters associated with genes that tend to remain repressed upon differentiation. Strikingly, bivalent CGI were the most affected by aberrant DNA hypermethylation in both CpG Island Methylator Phenotype-positive (CIMP+) and CIMP-negative tumors, suggesting that, besides transcriptional silencing in the pre-tumorigenic cells, the bivalent chromatin signature in hESCs is a key determinant of the instructive program for aberrant DNA methylation.
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Affiliation(s)
- Franck Court
- CNRS-UMR 6293, Clermont-Ferrand, 63001, France.,INSERM-U1103, Clermont-Ferrand, 63001, France.,Université Clermont Auvergne, GReD Laboratory, Clermont-Ferrand, 63000, France
| | - Philippe Arnaud
- CNRS-UMR 6293, Clermont-Ferrand, 63001, France.,INSERM-U1103, Clermont-Ferrand, 63001, France.,Université Clermont Auvergne, GReD Laboratory, Clermont-Ferrand, 63000, France
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22
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Crickard JB, Lee J, Lee TH, Reese JC. The elongation factor Spt4/5 regulates RNA polymerase II transcription through the nucleosome. Nucleic Acids Res 2017; 45:6362-6374. [PMID: 28379497 PMCID: PMC5499766 DOI: 10.1093/nar/gkx220] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 03/23/2017] [Indexed: 01/04/2023] Open
Abstract
RNA polymerase II (RNAPII) passes through the nucleosome in a coordinated manner, generating several intermediate nucleosomal states as it breaks and then reforms histone–DNA contacts ahead of and behind it, respectively. Several studies have defined transcription-induced nucleosome intermediates using only RNA Polymerase. However, RNAPII is decorated with elongation factors as it transcribes the genome. One such factor, Spt4/5, becomes an integral component of the elongation complex, making direct contact with the ‘jaws’ of RNAPII and nucleic acids in the transcription scaffold. We have characterized the effect of incorporating Spt4/5 into the elongation complex on transcription through the 601R nucleosome. Spt4/5 suppressed RNAPII pausing at the major H3/H4-induced arrest point, resulting in downstream re-positioning of RNAPII further into the nucleosome. Using a novel single molecule FRET system, we found that Spt4/5 affected the kinetics of DNA re-wrapping and stabilized a nucleosomal intermediate with partially unwrapped DNA behind RNAPII. Comparison of nucleosomes of different sequence polarities suggest that the strength of the DNA–histone interactions behind RNAPII specifies the Spt4/5 requirement. We propose that Spt4/5 may be important to coordinate the mechanical movement of RNAPII through the nucleosome with co-transcriptional chromatin modifications during transcription, which is affected by the strength of histone–DNA interactions.
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Affiliation(s)
- John B Crickard
- Department of Biochemistry and Molecular Biology, Center for Eukaryotic Gene Regulation, Penn State University, University Park, PA 16802, USA
| | - Jaehyoun Lee
- Department of Chemistry, Penn State University, University Park, PA 16802, USA
| | - Tae-Hee Lee
- Department of Chemistry, Penn State University, University Park, PA 16802, USA
| | - Joseph C Reese
- Department of Biochemistry and Molecular Biology, Center for Eukaryotic Gene Regulation, Penn State University, University Park, PA 16802, USA
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23
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Appling FD, Schneider DA, Lucius AL. Multisubunit RNA Polymerase Cleavage Factors Modulate the Kinetics and Energetics of Nucleotide Incorporation: An RNA Polymerase I Case Study. Biochemistry 2017; 56:5654-5662. [PMID: 28846843 DOI: 10.1021/acs.biochem.7b00370] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
All cellular RNA polymerases are influenced by protein factors that stimulate RNA polymerase-catalyzed cleavage of the nascent RNA. Despite divergence in amino acid sequence, these so-called "cleavage factors" appear to share a common mechanism of action. Cleavage factors associate with the polymerase through a conserved structural element of the polymerase known as the secondary channel or pore. This mode of association enables the cleavage factor to reach through the secondary channel into the polymerase active site to reorient the active site divalent metal ions. This reorientation converts the polymerase active site into a nuclease active site. Interestingly, eukaryotic RNA polymerases I and III (Pols I and III, respectively) have incorporated their cleavage factors as bona fide subunits known as A12.2 and C11, respectively. Although it is clear that A12.2 and C11 dramatically stimulate the polymerase's cleavage activity, it is not known if or how these subunits affect the polymerization mechanism. In this work we have used transient-state kinetic techniques to characterize a Pol I isoform lacking A12.2. Our data clearly demonstrate that the A12.2 subunit profoundly affects the kinetics and energetics of the elementary steps of Pol I-catalyzed nucleotide incorporation. Given the high degree of conservation between polymerase-cleavage factor interactions, these data indicate that cleavage factor-modulated nucleotide incorporation mechanisms may be common to all cellular RNA polymerases.
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Affiliation(s)
- Francis D Appling
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham , Birmingham, Alabama 35294, United States
| | - David A Schneider
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham , Birmingham, Alabama 35294, United States
| | - Aaron L Lucius
- Department of Chemistry, University of Alabama at Birmingham , Birmingham, Alabama 35294, United States
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24
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Multisubunit DNA-Dependent RNA Polymerases from Vaccinia Virus and Other Nucleocytoplasmic Large-DNA Viruses: Impressions from the Age of Structure. Microbiol Mol Biol Rev 2017; 81:81/3/e00010-17. [PMID: 28701329 DOI: 10.1128/mmbr.00010-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The past 17 years have been marked by a revolution in our understanding of cellular multisubunit DNA-dependent RNA polymerases (MSDDRPs) at the structural level. A parallel development over the past 15 years has been the emerging story of the giant viruses, which encode MSDDRPs. Here we link the two in an attempt to understand the specialization of multisubunit RNA polymerases in the domain of life encompassing the large nucleocytoplasmic DNA viruses (NCLDV), a superclade that includes the giant viruses and the biochemically well-characterized poxvirus vaccinia virus. The first half of this review surveys the recently determined structural biology of cellular RNA polymerases for a microbiology readership. The second half discusses a reannotation of MSDDRP subunits from NCLDV families and the apparent specialization of these enzymes by virus family and by subunit with regard to subunit or domain loss, subunit dissociability, endogenous control of polymerase arrest, and the elimination/customization of regulatory interactions that would confer higher-order cellular control. Some themes are apparent in linking subunit function to structure in the viral world: as with cellular RNA polymerases I and III and unlike cellular RNA polymerase II, the viral enzymes seem to opt for speed and processivity and seem to have eliminated domains associated with higher-order regulation. The adoption/loss of viral RNA polymerase proofreading functions may have played a part in matching intrinsic mutability to genome size.
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25
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Zheng S, Pan T, Ma C, Qiu D. Differential Gene Expression of Longan Under Simulated Acid Rain Stress. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2017; 98:726-731. [PMID: 28299408 DOI: 10.1007/s00128-017-2059-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 03/01/2017] [Indexed: 06/06/2023]
Abstract
Differential gene expression profile was studied in Dimocarpus longan Lour. in response to treatments of simulated acid rain with pH 2.5, 3.5, and a control (pH 5.6) using differential display reverse transcription polymerase chain reaction (DDRT-PCR). Results showed that mRNA differential display conditions were optimized to find an expressed sequence tag (EST) related with acid rain stress. The potential encoding products had 80% similarity with a transcription initiation factor IIF of Gossypium raimondii and 81% similarity with a protein product of Theobroma cacao. This fragment is the transcription factor activated by second messenger substances in longan leaves after signal perception of acid rain.
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Affiliation(s)
- Shan Zheng
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Tengfei Pan
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Cuilan Ma
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Dongliang Qiu
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
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26
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Malkusch N, Dörfler T, Nagy J, Eilert T, Michaelis J. smFRET experiments of the RNA polymerase II transcription initiation complex. Methods 2017; 120:115-124. [PMID: 28434999 DOI: 10.1016/j.ymeth.2017.04.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 03/21/2017] [Accepted: 04/14/2017] [Indexed: 01/23/2023] Open
Abstract
Single-molecule fluorescence and in particular single-molecule Förster Resonance Energy Transfer (smFRET) is a powerful tool to provide real-time information on the dynamic architecture of large macromolecular structures such as eukaryotic transcription initiation complexes. In contrast to other structural biology methods, not only structural details, but dynamics transitions are revealed thus closing in on the underlying molecular mechanisms. Here, we describe a comprehensive quantitative biophysical toolbox which can be used for rigorous analysis of dynamic protein-nucleic acid complexes and is applied to the study of eukaryotic transcription initiation. We present detailed protocols for the purification of all essential protein components of the minimal eukaryotic transcription initiation complex. Moreover, we demonstrate how elaborate strategies for site-specific protein labeling can be used to produce complexes with dye molecules attached to arbitrary desired positions. These complexes are then used for smFRET measurements. Moreover, we describe the Nano-Positioning System (NPS) which allows us to quantitatively use the results from a network of smFRET measurements to obtain structural information. With this we provide a toolbox to answer open questions which could not be addressed using methods like X-ray crystallography or cryo-electron microscopy.
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Affiliation(s)
- Nicole Malkusch
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Thilo Dörfler
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Julia Nagy
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Tobias Eilert
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Jens Michaelis
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
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27
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Lisica A, Grill SW. Optical tweezers studies of transcription by eukaryotic RNA polymerases. Biomol Concepts 2017; 8:1-11. [PMID: 28222010 DOI: 10.1515/bmc-2016-0028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/10/2017] [Indexed: 11/15/2022] Open
Abstract
Transcription is the first step in the expression of genetic information and it is carried out by large macromolecular enzymes called RNA polymerases. Transcription has been studied for many years and with a myriad of experimental techniques, ranging from bulk studies to high-resolution transcript sequencing. In this review, we emphasise the advantages of using single-molecule techniques, particularly optical tweezers, to study transcription dynamics. We give an overview of the latest results in the single-molecule transcription field, focusing on transcription by eukaryotic RNA polymerases. Finally, we evaluate recent quantitative models that describe the biophysics of RNA polymerase translocation and backtracking dynamics.
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Affiliation(s)
- Ana Lisica
- BIOTEC, Technical University Dresden, Tatzberg 47/49, D-01307 Dresden, Germany; and Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, D-01307 Dresden, Germany
| | - Stephan W Grill
- BIOTEC, Technical University Dresden, Tatzberg 47/49, D-01307 Dresden, Germany; and Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, D-01307 Dresden, Germany
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28
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Nemet J, Vidan N, Sopta M. A meta-analysis reveals complex regulatory properties at Taf14-repressed genes. BMC Genomics 2017; 18:175. [PMID: 28209126 PMCID: PMC5312515 DOI: 10.1186/s12864-017-3544-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 02/02/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Regulation of gene transcription in response to stress is central to a cell's ability to cope with environmental challenges. Taf14 is a YEATS domain protein in S.cerevisiae that physically associates with several transcriptionally relevant multisubunit complexes including the general transcription factors TFIID and TFIIF and the chromatin-modifying complexes SWI/SNF, INO80, RSC and NuA3. TAF14 deletion strains are sensitive to a variety of stresses suggesting that it plays a role in the transcriptional stress response. RESULTS In this report we survey published genome-wide transcriptome and occupancy data to define regulatory properties associated with Taf14-dependent genes. Our transcriptome analysis reveals that stress related, TATA-containing and SAGA-dependent genes were much more affected by TAF14 deletion than were TFIID-dependent genes. Comparison of Taf14 and multiple transcription factor occupancy at promoters genome-wide identified a group of proteins whose occupancy correlates with that of Taf14 and whose proximity to Taf14 suggests functional interactions. We show that Taf14-repressed genes tend to be extensively regulated, positively by SAGA complex and the stress dependent activators, Msn2/4 and negatively by a wide number of repressors that act upon promoter chromatin and TBP. CONCLUSIONS Taken together our analyses suggest a novel role for Taf14 in repression and derepression of stress induced genes, most probably as part of a regulatory network which includes Cyc8-Tup1, Srb10 and histone modifying enzymes.
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Affiliation(s)
- Josipa Nemet
- Department of molecular biology, Ruđer Bošković Institute, Bijenička 54, Zagreb, Croatia
| | - Nikolina Vidan
- Department of molecular biology, Ruđer Bošković Institute, Bijenička 54, Zagreb, Croatia
| | - Mary Sopta
- Department of molecular biology, Ruđer Bošković Institute, Bijenička 54, Zagreb, Croatia.
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29
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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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30
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Gaspard P. Template-Directed Copolymerization, Random Walks along Disordered Tracks, and Fractals. PHYSICAL REVIEW LETTERS 2016; 117:238101. [PMID: 27982621 DOI: 10.1103/physrevlett.117.238101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Indexed: 06/06/2023]
Abstract
In biology, template-directed copolymerization is the fundamental mechanism responsible for the synthesis of DNA, RNA, and proteins. More than 50 years have passed since the discovery of DNA structure and its role in coding genetic information. Yet, the kinetics and thermodynamics of information processing in DNA replication, transcription, and translation remain poorly understood. Challenging issues are the facts that DNA or RNA sequences constitute disordered media for the motion of polymerases or ribosomes while errors occur in copying the template. Here, it is shown that these issues can be addressed and sequence heterogeneity effects can be quantitatively understood within a framework revealing universal aspects of information processing at the molecular scale. In steady growth regimes, the local velocities of polymerases or ribosomes along the template are distributed as the continuous or fractal invariant set of a so-called iterated function system, which determines the copying error probabilities. The growth may become sublinear in time with a scaling exponent that can also be deduced from the iterated function system.
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Affiliation(s)
- Pierre Gaspard
- Center for Nonlinear Phenomena and Complex Systems, Université libre de Bruxelles (ULB), Code Postal 231, Campus Plaine, B-1050 Brussels, Belgium
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31
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Nucleosomal arrangement affects single-molecule transcription dynamics. Proc Natl Acad Sci U S A 2016; 113:12733-12738. [PMID: 27791062 DOI: 10.1073/pnas.1602764113] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In eukaryotes, gene expression depends on chromatin organization. However, how chromatin affects the transcription dynamics of individual RNA polymerases has remained elusive. Here, we use dual trap optical tweezers to study single yeast RNA polymerase II (Pol II) molecules transcribing along a DNA template with two nucleosomes. The slowdown and the changes in pausing behavior within the nucleosomal region allow us to determine a drift coefficient, χ, which characterizes the ability of the enzyme to recover from a nucleosomal backtrack. Notably, χ can be used to predict the probability to pass the first nucleosome. Importantly, the presence of a second nucleosome changes χ in a manner that depends on the spacing between the two nucleosomes, as well as on their rotational arrangement on the helical DNA molecule. Our results indicate that the ability of Pol II to pass the first nucleosome is increased when the next nucleosome is turned away from the first one to face the opposite side of the DNA template. These findings help to rationalize how chromatin arrangement affects Pol II transcription dynamics.
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32
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Ordu O, Lusser A, Dekker NH. Recent insights from in vitro single-molecule studies into nucleosome structure and dynamics. Biophys Rev 2016; 8:33-49. [PMID: 28058066 PMCID: PMC5167136 DOI: 10.1007/s12551-016-0212-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/17/2016] [Indexed: 01/04/2023] Open
Abstract
Eukaryotic DNA is tightly packed into a hierarchically ordered structure called chromatin in order to fit into the micron-scaled nucleus. The basic unit of chromatin is the nucleosome, which consists of a short piece of DNA wrapped around a core of eight histone proteins. In addition to their role in packaging DNA, nucleosomes impact the regulation of essential nuclear processes such as replication, transcription, and repair by controlling the accessibility of DNA. Thus, knowledge of this fundamental DNA-protein complex is crucial for understanding the mechanisms of gene control. While structural and biochemical studies over the past few decades have provided key insights into both the molecular composition and functional aspects of nucleosomes, these approaches necessarily average over large populations and times. In contrast, single-molecule methods are capable of revealing features of subpopulations and dynamic changes in the structure or function of biomolecules, rendering them a powerful complementary tool for probing mechanistic aspects of DNA-protein interactions. In this review, we highlight how these single-molecule approaches have recently yielded new insights into nucleosomal and subnucleosomal structures and dynamics.
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Affiliation(s)
- Orkide Ordu
- Bionanoscience Department, Kavli Institute of Nanoscience,, Delft University of Technology, Van der Maasweg 9,, 2629 HZ Delft, The Netherlands
| | - Alexandra Lusser
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Nynke H. Dekker
- Bionanoscience Department, Kavli Institute of Nanoscience,, Delft University of Technology, Van der Maasweg 9,, 2629 HZ Delft, The Netherlands
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33
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Abstract
The production of a single mRNA is the result of many sequential steps, from docking of transcription factors to polymerase initiation, elongation, splicing, and, finally, termination. Much of our knowledge about the fundamentals of RNA synthesis and processing come from ensemble in vitro biochemical measurements. Single-molecule approaches are very much in this same reductionist tradition but offer exquisite sensitivity in space and time along with the ability to observe heterogeneous behavior and actually manipulate macromolecules. These techniques can also be applied in vivo, allowing one to address questions in living cells that were previously restricted to reconstituted systems. In this review, we examine the unique insights that single-molecule techniques have yielded on the mechanisms of gene expression.
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Affiliation(s)
- Huimin Chen
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Daniel R Larson
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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34
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Sharma N. Regulation of RNA polymerase II-mediated transcriptional elongation: Implications in human disease. IUBMB Life 2016; 68:709-16. [DOI: 10.1002/iub.1538] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 07/14/2016] [Indexed: 01/03/2023]
Affiliation(s)
- Nimisha Sharma
- University School of Biotechnology, G.G.S. Indraprastha University; Dwarka New Delhi 110078 India
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35
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Ucuncuoglu S, Engel KL, Purohit PK, Dunlap DD, Schneider DA, Finzi L. Direct Characterization of Transcription Elongation by RNA Polymerase I. PLoS One 2016; 11:e0159527. [PMID: 27455049 PMCID: PMC4959687 DOI: 10.1371/journal.pone.0159527] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 07/04/2016] [Indexed: 11/18/2022] Open
Abstract
RNA polymerase I (Pol I) transcribes ribosomal DNA and is responsible for more than 60% of transcription in a growing cell. Despite this fundamental role that directly impacts cell growth and proliferation, the kinetics of transcription by Pol I are poorly understood. This study provides direct characterization of S. Cerevisiae Pol I transcription elongation using tethered particle microscopy (TPM). Pol I was shown to elongate at an average rate of approximately 20 nt/s. However, the maximum speed observed was, in average, about 60 nt/s, comparable to the rate calculated based on the in vivo number of active genes, the cell division rate and the number of engaged polymerases observed in EM images. Addition of RNA endonucleases to the TPM elongation assays enhanced processivity. Together, these data suggest that additional transcription factors contribute to efficient and processive transcription elongation by RNA polymerase I in vivo.
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Affiliation(s)
- Suleyman Ucuncuoglu
- Physics Department, Emory University, Atlanta, GA, 30322, United States of America
| | - Krysta L. Engel
- Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, 35294, United States of America
| | - Prashant K. Purohit
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, 19104, United States of America
| | - David D. Dunlap
- Physics Department, Emory University, Atlanta, GA, 30322, United States of America
| | - David A. Schneider
- Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, 35294, United States of America
- * E-mail: (LF); (DAS)
| | - Laura Finzi
- Physics Department, Emory University, Atlanta, GA, 30322, United States of America
- * E-mail: (LF); (DAS)
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36
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Pilsl M, Crucifix C, Papai G, Krupp F, Steinbauer R, Griesenbeck J, Milkereit P, Tschochner H, Schultz P. Structure of the initiation-competent RNA polymerase I and its implication for transcription. Nat Commun 2016; 7:12126. [PMID: 27418187 PMCID: PMC4947174 DOI: 10.1038/ncomms12126] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 06/02/2016] [Indexed: 01/12/2023] Open
Abstract
Eukaryotic RNA polymerase I (Pol I) is specialized in rRNA gene transcription synthesizing up to 60% of cellular RNA. High level rRNA production relies on efficient binding of initiation factors to the rRNA gene promoter and recruitment of Pol I complexes containing initiation factor Rrn3. Here, we determine the cryo-EM structure of the Pol I-Rrn3 complex at 7.5 Å resolution, and compare it with Rrn3-free monomeric and dimeric Pol I. We observe that Rrn3 contacts the Pol I A43/A14 stalk and subunits A190 and AC40, that association re-organizes the Rrn3 interaction interface, thereby preventing Pol I dimerization; and Rrn3-bound and monomeric Pol I differ from the dimeric enzyme in cleft opening, and localization of the A12.2 C-terminus in the active centre. Our findings thus support a dual role for Rrn3 in transcription initiation to stabilize a monomeric initiation competent Pol I and to drive pre-initiation complex formation. Eukaryotic RNA polymerase I (Pol I) is responsible for the transcription of rRNA genes. Here the authors determine the cryo-EM structure of the Pol I-Rrn3 complex, providing insight into how Rrn3 stabilizes the monomeric initiation competent Pol I to drive pre-initiation complex formation.
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Affiliation(s)
- Michael Pilsl
- Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Institut für Biochemie, Genetik und Mikrobiologie, Lehrstuhl Biochemie III, 93053 Regensburg, Germany
| | - Corinne Crucifix
- Department of Integrated Structural Biology, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire) INSERM, U964; CNRS/Strasbourg University, UMR7104 1, rue Laurent Fries, BP10142, 67404 Illkirch, France
| | - Gabor Papai
- Department of Integrated Structural Biology, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire) INSERM, U964; CNRS/Strasbourg University, UMR7104 1, rue Laurent Fries, BP10142, 67404 Illkirch, France
| | - Ferdinand Krupp
- Department of Integrated Structural Biology, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire) INSERM, U964; CNRS/Strasbourg University, UMR7104 1, rue Laurent Fries, BP10142, 67404 Illkirch, France
| | - Robert Steinbauer
- Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Institut für Biochemie, Genetik und Mikrobiologie, Lehrstuhl Biochemie III, 93053 Regensburg, Germany
| | - Joachim Griesenbeck
- Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Institut für Biochemie, Genetik und Mikrobiologie, Lehrstuhl Biochemie III, 93053 Regensburg, Germany
| | - Philipp Milkereit
- Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Institut für Biochemie, Genetik und Mikrobiologie, Lehrstuhl Biochemie III, 93053 Regensburg, Germany
| | - Herbert Tschochner
- Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Institut für Biochemie, Genetik und Mikrobiologie, Lehrstuhl Biochemie III, 93053 Regensburg, Germany
| | - Patrick Schultz
- Department of Integrated Structural Biology, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire) INSERM, U964; CNRS/Strasbourg University, UMR7104 1, rue Laurent Fries, BP10142, 67404 Illkirch, France
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37
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Roldán É, Lisica A, Sánchez-Taltavull D, Grill SW. Stochastic resetting in backtrack recovery by RNA polymerases. Phys Rev E 2016; 93:062411. [PMID: 27415302 DOI: 10.1103/physreve.93.062411] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Indexed: 11/07/2022]
Abstract
Transcription is a key process in gene expression, in which RNA polymerases produce a complementary RNA copy from a DNA template. RNA polymerization is frequently interrupted by backtracking, a process in which polymerases perform a random walk along the DNA template. Recovery of polymerases from the transcriptionally inactive backtracked state is determined by a kinetic competition between one-dimensional diffusion and RNA cleavage. Here we describe backtrack recovery as a continuous-time random walk, where the time for a polymerase to recover from a backtrack of a given depth is described as a first-passage time of a random walker to reach an absorbing state. We represent RNA cleavage as a stochastic resetting process and derive exact expressions for the recovery time distributions and mean recovery times from a given initial backtrack depth for both continuous and discrete-lattice descriptions of the random walk. We show that recovery time statistics do not depend on the discreteness of the DNA lattice when the rate of one-dimensional diffusion is large compared to the rate of cleavage.
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Affiliation(s)
- Édgar Roldán
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany.,Center for Advancing Electronics Dresden, cfaed, Dresden, Germany.,GISC - Grupo Interdisciplinar de Sistemas Complejos, Madrid, Spain
| | - Ana Lisica
- BIOTEC, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | | | - Stephan W Grill
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany.,BIOTEC, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
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38
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Saldi T, Cortazar MA, Sheridan RM, Bentley DL. Coupling of RNA Polymerase II Transcription Elongation with Pre-mRNA Splicing. J Mol Biol 2016; 428:2623-2635. [PMID: 27107644 DOI: 10.1016/j.jmb.2016.04.017] [Citation(s) in RCA: 176] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/27/2016] [Accepted: 04/12/2016] [Indexed: 01/07/2023]
Abstract
Pre-mRNA maturation frequently occurs at the same time and place as transcription by RNA polymerase II. The co-transcriptionality of mRNA processing has permitted the evolution of mechanisms that functionally couple transcription elongation with diverse events that occur on the nascent RNA. This review summarizes the current understanding of the relationship between transcriptional elongation through a chromatin template and co-transcriptional splicing including alternative splicing decisions that affect the expression of most human genes.
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Affiliation(s)
- Tassa Saldi
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, P.O. Box 6511, Aurora, CO 80045, USA
| | - Michael A Cortazar
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, P.O. Box 6511, Aurora, CO 80045, USA
| | - Ryan M Sheridan
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, P.O. Box 6511, Aurora, CO 80045, USA
| | - David L Bentley
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, P.O. Box 6511, Aurora, CO 80045, USA.
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39
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Abstract
During DNA transcription, RNA polymerases often adopt inactive backtracked states. Recovery from backtracks can occur by 1D diffusion or cleavage of backtracked RNA, but how polymerases make this choice is unknown. Here, we use single-molecule optical tweezers experiments and stochastic theory to show that the choice of a backtrack recovery mechanism is determined by a kinetic competition between 1D diffusion and RNA cleavage. Notably, RNA polymerase I (Pol I) and Pol II recover from shallow backtracks by 1D diffusion, use RNA cleavage to recover from intermediary depths, and are unable to recover from extensive backtracks. Furthermore, Pol I and Pol II use distinct mechanisms to avoid nonrecoverable backtracking. Pol I is protected by its subunit A12.2, which decreases the rate of 1D diffusion and enables transcript cleavage up to 20 nt. In contrast, Pol II is fully protected through association with the cleavage stimulatory factor TFIIS, which enables rapid recovery from any depth by RNA cleavage. Taken together, we identify distinct backtrack recovery strategies of Pol I and Pol II, shedding light on the evolution of cellular functions of these key enzymes.
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40
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Maliszewska-Olejniczak K, Gruchota J, Gromadka R, Denby Wilkes C, Arnaiz O, Mathy N, Duharcourt S, Bétermier M, Nowak JK. TFIIS-Dependent Non-coding Transcription Regulates Developmental Genome Rearrangements. PLoS Genet 2015; 11:e1005383. [PMID: 26177014 PMCID: PMC4503560 DOI: 10.1371/journal.pgen.1005383] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 06/22/2015] [Indexed: 02/07/2023] Open
Abstract
Because of their nuclear dimorphism, ciliates provide a unique opportunity to study the role of non-coding RNAs (ncRNAs) in the communication between germline and somatic lineages. In these unicellular eukaryotes, a new somatic nucleus develops at each sexual cycle from a copy of the zygotic (germline) nucleus, while the old somatic nucleus degenerates. In the ciliate Paramecium tetraurelia, the genome is massively rearranged during this process through the reproducible elimination of repeated sequences and the precise excision of over 45,000 short, single-copy Internal Eliminated Sequences (IESs). Different types of ncRNAs resulting from genome-wide transcription were shown to be involved in the epigenetic regulation of genome rearrangements. To understand how ncRNAs are produced from the entire genome, we have focused on a homolog of the TFIIS elongation factor, which regulates RNA polymerase II transcriptional pausing. Six TFIIS-paralogs, representing four distinct families, can be found in P. tetraurelia genome. Using RNA interference, we showed that TFIIS4, which encodes a development-specific TFIIS protein, is essential for the formation of a functional somatic genome. Molecular analyses and high-throughput DNA sequencing upon TFIIS4 RNAi demonstrated that TFIIS4 is involved in all kinds of genome rearrangements, including excision of ~48% of IESs. Localization of a GFP-TFIIS4 fusion revealed that TFIIS4 appears specifically in the new somatic nucleus at an early developmental stage, before IES excision. RT-PCR experiments showed that TFIIS4 is necessary for the synthesis of IES-containing non-coding transcripts. We propose that these IES+ transcripts originate from the developing somatic nucleus and serve as pairing substrates for germline-specific short RNAs that target elimination of their homologous sequences. Our study, therefore, connects the onset of zygotic non coding transcription to the control of genome plasticity in Paramecium, and establishes for the first time a specific role of TFIIS in non-coding transcription in eukaryotes. Paramecium tetraurelia provides an excellent model for studying the mechanisms involved in the production of non-coding transcripts and their mode of action. Different types of non-coding RNAs (ncRNAs) were shown to be implicated in the programmed DNA elimination process that occurs in this organism. At each sexual cycle, during development of the somatic nucleus from the germline nucleus, the genome is massively rearranged through the reproducible elimination of germline-specific sequences including thousands of short, single copy, non-coding Internal Eliminated Sequences (IES). Here, we demonstrate, using RNA interference, that the TFIIS4 gene encoding a development-specific homolog of RNA polymerase II elongation factor TFIIS, is indispensable for ncRNA synthesis in the new somatic nucleus. TFIIS4 depletion impairs the assembly of a functional somatic genome and affects excision of a large fraction of IESs, which leads to strong lethality in the sexual progeny. We propose that TFIIS4-dependent ncRNAs provide an important component of the molecular machinery that is responsible for developmental genome remodeling in Paramecium.
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Affiliation(s)
| | - Julita Gruchota
- Institute of Biochemistry and Biophysics, PAS, Warsaw, Poland
| | - Robert Gromadka
- Institute of Biochemistry and Biophysics, PAS, Warsaw, Poland
| | - Cyril Denby Wilkes
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris Sud, Gif-sur-Yvette, France
| | - Olivier Arnaiz
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris Sud, Gif-sur-Yvette, France
| | - Nathalie Mathy
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris Sud, Gif-sur-Yvette, France
| | - Sandra Duharcourt
- Institut Jacques Monod, CNRS, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Mireille Bétermier
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris Sud, Gif-sur-Yvette, France
| | - Jacek K. Nowak
- Institute of Biochemistry and Biophysics, PAS, Warsaw, Poland
- * E-mail:
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Ccr4-Not and TFIIS Function Cooperatively To Rescue Arrested RNA Polymerase II. Mol Cell Biol 2015; 35:1915-25. [PMID: 25776559 DOI: 10.1128/mcb.00044-15] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 03/11/2015] [Indexed: 12/13/2022] Open
Abstract
Expression of the genome requires RNA polymerase II (RNAPII) to transcribe across many natural and unnatural barriers, and this transcription across barriers is facilitated by protein complexes called elongation factors (EFs). Genetic studies in Saccharomyces cerevisiae yeast suggest that multiple EFs collaborate to assist RNAPII in completing the transcription of genes, but the molecular mechanisms of how they cooperate to promote elongation are not well understood. The Ccr4-Not complex participates in multiple steps of mRNA metabolism and has recently been shown to be an EF. Here we describe how Ccr4-Not and TFIIS cooperate to stimulate elongation. We find that Ccr4-Not and TFIIS mutations show synthetically enhanced phenotypes, and biochemical analyses indicate that Ccr4-Not and TFIIS work synergistically to reactivate arrested RNAPII. Ccr4-Not increases the recruitment of TFIIS into elongation complexes and enhances the cleavage of the displaced transcript in backtracked RNAPII. This is mediated by an interaction between Ccr4-Not and the N terminus of TFIIS. In addition to revealing insights into how these two elongation factors cooperate to promote RNAPII elongation, our study extends the growing body of evidence suggesting that the N terminus of TFIIS acts as a docking/interacting site that allows it to synergize with other EFs to promote RNAPII transcription.
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Jordán-Pla A, Gupta I, de Miguel-Jiménez L, Steinmetz LM, Chávez S, Pelechano V, Pérez-Ortín JE. Chromatin-dependent regulation of RNA polymerases II and III activity throughout the transcription cycle. Nucleic Acids Res 2014; 43:787-802. [PMID: 25550430 PMCID: PMC4333398 DOI: 10.1093/nar/gku1349] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The particular behaviour of eukaryotic RNA polymerases along different gene regions and amongst distinct gene functional groups is not totally understood. To cast light onto the alternative active or backtracking states of RNA polymerase II, we have quantitatively mapped active RNA polymerases at a high resolution following a new biotin-based genomic run-on (BioGRO) technique. Compared with conventional profiling with chromatin immunoprecipitation, the analysis of the BioGRO profiles in Saccharomyces cerevisiae shows that RNA polymerase II has unique activity profiles at both gene ends, which are highly dependent on positioned nucleosomes. This is the first demonstration of the in vivo influence of positioned nucleosomes on transcription elongation. The particular features at the 5' end and around the polyadenylation site indicate that this polymerase undergoes extensive specific-activity regulation in the initial and final transcription elongation phases. The genes encoding for ribosomal proteins show distinctive features at both ends. BioGRO also provides the first nascentome analysis for RNA polymerase III, which indicates that transcription of tRNA genes is poorly regulated at the individual copy level. The present study provides a novel perspective of the transcription cycle that incorporates inactivation/reactivation as an important aspect of RNA polymerase dynamics.
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Affiliation(s)
- Antonio Jordán-Pla
- Departamento de Bioquímica y Biología Molecular and ERI Biotecmed, Facultad de Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain
| | - Ishaan Gupta
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Lola de Miguel-Jiménez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, 41013 Seville, Spain
| | - Lars M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany Stanford University School of Medicine, Department of Genetics, Stanford, CA 94305, USA Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304, USA
| | - Sebastián Chávez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, 41013 Seville, Spain
| | - Vicent Pelechano
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - José E Pérez-Ortín
- Departamento de Bioquímica y Biología Molecular and ERI Biotecmed, Facultad de Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain
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43
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Transcribing through the nucleosome. Trends Biochem Sci 2014; 39:577-86. [DOI: 10.1016/j.tibs.2014.10.004] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 10/06/2014] [Accepted: 10/07/2014] [Indexed: 11/20/2022]
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Transcription factors TFIIF and TFIIS promote transcript elongation by RNA polymerase II by synergistic and independent mechanisms. Proc Natl Acad Sci U S A 2014; 111:6642-7. [PMID: 24733897 DOI: 10.1073/pnas.1405181111] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recent evidence suggests that transcript elongation by RNA polymerase II (RNAPII) is regulated by mechanical cues affecting the entry into, and exit from, transcriptionally inactive states, including pausing and arrest. We present a single-molecule optical-trapping study of the interactions of RNAPII with transcription elongation factors TFIIS and TFIIF, which affect these processes. By monitoring the response of elongation complexes containing RNAPII and combinations of TFIIF and TFIIS to controlled mechanical loads, we find that both transcription factors are independently capable of restoring arrested RNAPII to productive elongation. TFIIS, in addition to its established role in promoting transcript cleavage, is found to relieve arrest by a second, cleavage-independent mechanism. TFIIF synergistically enhances some, but not all, of the activities of TFIIS. These studies also uncovered unexpected insights into the mechanisms underlying transient pauses. The direct visualization of pauses at near-base-pair resolution, together with the load dependence of the pause-entry phase, suggests that two distinct mechanisms may be at play: backtracking under forces that hinder transcription and a backtrack-independent activity under assisting loads. The measured pause lifetime distributions are inconsistent with prevailing views of backtracking as a purely diffusive process, suggesting instead that the extent of backtracking may be modulated by mechanisms intrinsic to RNAPII. Pauses triggered by inosine triphosphate misincorporation led to backtracking, even under assisting loads, and their lifetimes were reduced by TFIIS, particularly when aided by TFIIF. Overall, these experiments provide additional insights into how obstacles to transcription may be overcome by the concerted actions of multiple accessory factors.
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