1
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Adebali O, Yang Y, Neupane P, Dike NI, Boltz JL, Kose C, Braunstein M, Selby CP, Sancar A, Lindsey-Boltz LA. The Mfd protein is the transcription-repair coupling factor (TRCF) in Mycobacterium smegmatis. J Biol Chem 2023; 299:103009. [PMID: 36775124 PMCID: PMC10023983 DOI: 10.1016/j.jbc.2023.103009] [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: 12/22/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 02/12/2023] Open
Abstract
In vitro and in vivo experiments with Escherichia coli have shown that the Mfd translocase is responsible for transcription-coupled repair, a subpathway of nucleotide excision repair involving the faster rate of repair of the transcribed strand than the nontranscribed strand. Even though the mfd gene is conserved in all bacterial lineages, there is only limited information on whether it performs the same function in other bacterial species. Here, by genome scale analysis of repair of UV-induced cyclobutane pyrimidine dimers, we find that the Mfd protein is the transcription-repair coupling factor in Mycobacterium smegmatis. This finding, combined with the inverted strandedness of UV-induced mutations in WT and mfd-E. coli and Bacillus subtilis indicate that the Mfd protein is the universal transcription-repair coupling factor in bacteria.
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Affiliation(s)
- Ogun Adebali
- Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Türkiye; Department of Computational Science - Biological Sciences, TÜBİTAK Research Institute for Fundamental Sciences, Gebze, Türkiye
| | - Yanyan Yang
- Department of Biochemistry and Biophysics, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Pradeep Neupane
- Department of Microbiology and Immunology, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Nneka I Dike
- Department of Biochemistry and Biophysics, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Julia L Boltz
- Department of Biochemistry and Biophysics, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Cansu Kose
- Department of Biochemistry and Biophysics, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Miriam Braunstein
- Department of Microbiology and Immunology, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Christopher P Selby
- Department of Biochemistry and Biophysics, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA.
| | - Laura A Lindsey-Boltz
- Department of Biochemistry and Biophysics, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
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2
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Paudel BP, Xu ZQ, Jergic S, Oakley AJ, Sharma N, Brown SHJ, Bouwer JC, Lewis PJ, Dixon NE, van Oijen AM, Ghodke H. Mechanism of transcription modulation by the transcription-repair coupling factor. Nucleic Acids Res 2022; 50:5688-5712. [PMID: 35641110 PMCID: PMC9177983 DOI: 10.1093/nar/gkac449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 05/06/2022] [Accepted: 05/13/2022] [Indexed: 11/27/2022] Open
Abstract
Elongation by RNA polymerase is dynamically modulated by accessory factors. The transcription-repair coupling factor (TRCF) recognizes paused/stalled RNAPs and either rescues transcription or initiates transcription termination. Precisely how TRCFs choose to execute either outcome remains unclear. With Escherichia coli as a model, we used single-molecule assays to study dynamic modulation of elongation by Mfd, the bacterial TRCF. We found that nucleotide-bound Mfd converts the elongation complex (EC) into a catalytically poised state, presenting the EC with an opportunity to restart transcription. After long-lived residence in this catalytically poised state, ATP hydrolysis by Mfd remodels the EC through an irreversible process leading to loss of the RNA transcript. Further, biophysical studies revealed that the motor domain of Mfd binds and partially melts DNA containing a template strand overhang. The results explain pathway choice determining the fate of the EC and provide a molecular mechanism for transcription modulation by TRCF.
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Affiliation(s)
- Bishnu P Paudel
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Zhi-Qiang Xu
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Slobodan Jergic
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Aaron J Oakley
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Nischal Sharma
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Simon H J Brown
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.,ARC Industrial Transformation Training Centre for Cryo-electron Microscopy of Membrane Proteins, University of Wollongong, Wollongong, NSW 2522, Australia
| | - James C Bouwer
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.,ARC Industrial Transformation Training Centre for Cryo-electron Microscopy of Membrane Proteins, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Peter J Lewis
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia.,School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Nicholas E Dixon
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.,ARC Industrial Transformation Training Centre for Cryo-electron Microscopy of Membrane Proteins, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Antoine M van Oijen
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.,ARC Industrial Transformation Training Centre for Cryo-electron Microscopy of Membrane Proteins, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Harshad Ghodke
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
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3
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Agapov A, Olina A, Kulbachinskiy A. OUP accepted manuscript. Nucleic Acids Res 2022; 50:3018-3041. [PMID: 35323981 PMCID: PMC8989532 DOI: 10.1093/nar/gkac174] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 02/26/2022] [Accepted: 03/03/2022] [Indexed: 11/14/2022] Open
Abstract
Cellular DNA is continuously transcribed into RNA by multisubunit RNA polymerases (RNAPs). The continuity of transcription can be disrupted by DNA lesions that arise from the activities of cellular enzymes, reactions with endogenous and exogenous chemicals or irradiation. Here, we review available data on translesion RNA synthesis by multisubunit RNAPs from various domains of life, define common principles and variations in DNA damage sensing by RNAP, and consider existing controversies in the field of translesion transcription. Depending on the type of DNA lesion, it may be correctly bypassed by RNAP, or lead to transcriptional mutagenesis, or result in transcription stalling. Various lesions can affect the loading of the templating base into the active site of RNAP, or interfere with nucleotide binding and incorporation into RNA, or impair RNAP translocation. Stalled RNAP acts as a sensor of DNA damage during transcription-coupled repair. The outcome of DNA lesion recognition by RNAP depends on the interplay between multiple transcription and repair factors, which can stimulate RNAP bypass or increase RNAP stalling, and plays the central role in maintaining the DNA integrity. Unveiling the mechanisms of translesion transcription in various systems is thus instrumental for understanding molecular pathways underlying gene regulation and genome stability.
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Affiliation(s)
- Aleksei Agapov
- Correspondence may also be addressed to Aleksei Agapov. Tel: +7 499 196 0015; Fax: +7 499 196 0015;
| | - Anna Olina
- Institute of Molecular Genetics, National Research Center “Kurchatov Institute” Moscow 123182, Russia
| | - Andrey Kulbachinskiy
- To whom correspondence should be addressed. Tel: +7 499 196 0015; Fax: +7 499 196 0015;
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4
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Single-molecule studies of helicases and translocases in prokaryotic genome-maintenance pathways. DNA Repair (Amst) 2021; 108:103229. [PMID: 34601381 DOI: 10.1016/j.dnarep.2021.103229] [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: 05/03/2021] [Revised: 09/13/2021] [Accepted: 09/16/2021] [Indexed: 11/22/2022]
Abstract
Helicases involved in genomic maintenance are a class of nucleic-acid dependent ATPases that convert the energy of ATP hydrolysis into physical work to execute irreversible steps in DNA replication, repair, and recombination. Prokaryotic helicases provide simple models to understand broadly conserved molecular mechanisms involved in manipulating nucleic acids during genome maintenance. Our understanding of the catalytic properties, mechanisms of regulation, and roles of prokaryotic helicases in DNA metabolism has been assembled through a combination of genetic, biochemical, and structural methods, further refined by single-molecule approaches. Together, these investigations have constructed a framework for understanding the mechanisms that maintain genomic integrity in cells. This review discusses recent single-molecule insights into molecular mechanisms of prokaryotic helicases and translocases.
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5
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Deaconescu AM. Mfd - at the crossroads of bacterial DNA repair, transcriptional regulation and molecular evolvability. Transcription 2021; 12:156-170. [PMID: 34674614 PMCID: PMC8632110 DOI: 10.1080/21541264.2021.1982628] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 09/06/2021] [Accepted: 09/14/2021] [Indexed: 12/21/2022] Open
Abstract
For survival, bacteria need to continuously evolve and adapt to complex environments, including those that may impact the integrity of the DNA, the repository of genetic information to be passed on to future generations. The multiple factors of DNA repair share the substrate on which they operate with other key cellular machineries, principally those of replication and transcription, implying a high degree of coordination of DNA-based activities. In this review, I focus on progress made in the understanding of the protein factors operating at the crossroads of these three fundamental processes, with emphasis on the mutation frequency decline protein (Mfd, aka TRCF). Although Mfd research has a rich history that goes back in time for more than half a century, recent reports hint that much remains to be uncovered. I argue that besides being a transcription-repair coupling factor (TRCF), Mfd is also a global regulator of transcription and a pro-mutagenic factor, and that the way it interfaces with transcription, replication and nucleotide excision repair makes it an attractive candidate for the development of strategies to curb molecular evolution, hence, antibiotic resistance.
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Affiliation(s)
- Alexandra M. Deaconescu
- CONTACT Alexandra M. Deaconescu Molecular Biology, Cell Biology and Biochemistry, Laboratories of Molecular Medicine, Brown University, 70 Ship St. G-E4, Providence, RI02903, USA
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6
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Lindsey-Boltz LA, Sancar A. The Transcription-Repair Coupling Factor Mfd Prevents and Promotes Mutagenesis in a Context-Dependent Manner. Front Mol Biosci 2021; 8:668290. [PMID: 34095223 PMCID: PMC8174841 DOI: 10.3389/fmolb.2021.668290] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/14/2021] [Indexed: 12/29/2022] Open
Abstract
The mfd (mutation frequency decline) gene was identified by screening an auxotrophic Escherichia coli strain exposed to UV and held in a minimal medium before plating onto rich or minimal agar plates. It was found that, under these conditions, holding cells in minimal (nongrowth) conditions resulted in mutations that enabled cells to grow on minimal media. Using this observation as a starting point, a mutant was isolated that failed to mutate to auxotrophy under the prescribed conditions, and the gene responsible for this phenomenon (mutation frequency decline) was named mfd. Later work revealed that mfd encoded a translocase that recognizes a stalled RNA polymerase (RNAP) at damage sites and binds to the stalled RNAP, recruits the nucleotide excision repair damage recognition complex UvrA2UvrB to the site, and facilitates damage recognition and repair while dissociating the stalled RNAP from the DNA along with the truncated RNA. Recent single-molecule and genome-wide repair studies have revealed time-resolved features and structural aspects of this transcription-coupled repair (TCR) phenomenon. Interestingly, recent work has shown that in certain bacterial species, mfd also plays roles in recombination, bacterial virulence, and the development of drug resistance.
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Affiliation(s)
- Laura A Lindsey-Boltz
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC, United States
| | - Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC, United States
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7
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Martin HA, Sundararajan A, Ermi TS, Heron R, Gonzales J, Lee K, Anguiano-Mendez D, Schilkey F, Pedraza-Reyes M, Robleto EA. Mfd Affects Global Transcription and the Physiology of Stressed Bacillus subtilis Cells. Front Microbiol 2021; 12:625705. [PMID: 33603726 PMCID: PMC7885715 DOI: 10.3389/fmicb.2021.625705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/07/2021] [Indexed: 11/13/2022] Open
Abstract
For several decades, Mfd has been studied as the bacterial transcription-coupled repair factor. However, recent observations indicate that this factor influences cell functions beyond DNA repair. Our lab recently described a role for Mfd in disulfide stress that was independent of its function in nucleotide excision repair and base excision repair. Because reports showed that Mfd influenced transcription of single genes, we investigated the global differences in transcription in wild-type and mfd mutant growth-limited cells in the presence and absence of diamide. Surprisingly, we found 1,997 genes differentially expressed in Mfd– cells in the absence of diamide. Using gene knockouts, we investigated the effect of genetic interactions between Mfd and the genes in its regulon on the response to disulfide stress. Interestingly, we found that Mfd interactions were complex and identified additive, epistatic, and suppressor effects in the response to disulfide stress. Pathway enrichment analysis of our RNASeq assay indicated that major biological functions, including translation, endospore formation, pyrimidine metabolism, and motility, were affected by the loss of Mfd. Further, our RNASeq findings correlated with phenotypic changes in growth in minimal media, motility, and sensitivity to antibiotics that target the cell envelope, transcription, and DNA replication. Our results suggest that Mfd has profound effects on the modulation of the transcriptome and on bacterial physiology, particularly in cells experiencing nutritional and oxidative stress.
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Affiliation(s)
- Holly Anne Martin
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | | | - Tatiana S Ermi
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Robert Heron
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Jason Gonzales
- West Career and Technical Academy, Las Vegas, NV, United States
| | - Kaiden Lee
- The College of Idaho, Caldwell, ID, United States
| | - Diana Anguiano-Mendez
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Faye Schilkey
- National Center for Genome Resources, Santa Fe, NM, United States
| | - Mario Pedraza-Reyes
- Division of Natural and Exact Sciences, Department of Biology, University of Guanajuato, Guanajuato, Mexico
| | - Eduardo A Robleto
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
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8
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Kang JY, Llewellyn E, Chen J, Olinares PDB, Brewer J, Chait BT, Campbell EA, Darst SA. Structural basis for transcription complex disruption by the Mfd translocase. eLife 2021; 10:62117. [PMID: 33480355 PMCID: PMC7864632 DOI: 10.7554/elife.62117] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 01/21/2021] [Indexed: 12/30/2022] Open
Abstract
Transcription-coupled repair (TCR) is a sub-pathway of nucleotide excision repair (NER) that preferentially removes lesions from the template-strand (t-strand) that stall RNA polymerase (RNAP) elongation complexes (ECs). Mfd mediates TCR in bacteria by removing the stalled RNAP concealing the lesion and recruiting Uvr(A)BC. We used cryo-electron microscopy to visualize Mfd engaging with a stalled EC and attempting to dislodge the RNAP. We visualized seven distinct Mfd-EC complexes in both ATP and ADP-bound states. The structures explain how Mfd is remodeled from its repressed conformation, how the UvrA-interacting surface of Mfd is hidden during most of the remodeling process to prevent premature engagement with the NER pathway, how Mfd alters the RNAP conformation to facilitate disassembly, and how Mfd forms a processive translocation complex after dislodging the RNAP. Our results reveal an elaborate mechanism for how Mfd kinetically discriminates paused from stalled ECs and disassembles stalled ECs to initiate TCR.
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Affiliation(s)
- Jin Young Kang
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, United States
| | - Eliza Llewellyn
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, United States
| | - James Chen
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, United States
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Joshua Brewer
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, United States
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, United States
| | - Seth A Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, United States
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9
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Kraithong T, Hartley S, Jeruzalmi D, Pakotiprapha D. A Peek Inside the Machines of Bacterial Nucleotide Excision Repair. Int J Mol Sci 2021; 22:ijms22020952. [PMID: 33477956 PMCID: PMC7835731 DOI: 10.3390/ijms22020952] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 12/13/2022] Open
Abstract
Double stranded DNA (dsDNA), the repository of genetic information in bacteria, archaea and eukaryotes, exhibits a surprising instability in the intracellular environment; this fragility is exacerbated by exogenous agents, such as ultraviolet radiation. To protect themselves against the severe consequences of DNA damage, cells have evolved at least six distinct DNA repair pathways. Here, we review recent key findings of studies aimed at understanding one of these pathways: bacterial nucleotide excision repair (NER). This pathway operates in two modes: a global genome repair (GGR) pathway and a pathway that closely interfaces with transcription by RNA polymerase called transcription-coupled repair (TCR). Below, we discuss the architecture of key proteins in bacterial NER and recent biochemical, structural and single-molecule studies that shed light on the lesion recognition steps of both the GGR and the TCR sub-pathways. Although a great deal has been learned about both of these sub-pathways, several important questions, including damage discrimination, roles of ATP and the orchestration of protein binding and conformation switching, remain to be addressed.
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Affiliation(s)
- Thanyalak Kraithong
- Doctor of Philosophy Program in Biochemistry (International Program), Faculty of Science, Mahidol University, Bangkok 10400, Thailand;
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
- Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Silas Hartley
- Department of Chemistry and Biochemistry, City College of New York, New York, NY 10031, USA;
- Doctor of Philosophy Programs in Biochemistry, Biology and Chemistry, The Graduate Center of the City University of New York, New York, NY 10016, USA
| | - David Jeruzalmi
- Department of Chemistry and Biochemistry, City College of New York, New York, NY 10031, USA;
- Doctor of Philosophy Programs in Biochemistry, Biology and Chemistry, The Graduate Center of the City University of New York, New York, NY 10016, USA
- Correspondence: (D.J.); (D.P.)
| | - Danaya Pakotiprapha
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
- Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
- Correspondence: (D.J.); (D.P.)
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10
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Kaur G, Kapoor S, Kaundal S, Dutta D, Thakur KG. Structure-Guided Designing and Evaluation of Peptides Targeting Bacterial Transcription. Front Bioeng Biotechnol 2020; 8:797. [PMID: 33014990 PMCID: PMC7505949 DOI: 10.3389/fbioe.2020.00797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/22/2020] [Indexed: 11/17/2022] Open
Abstract
The mycobacterial RNA polymerase (RNAP) is an essential and validated drug target for developing antibacterial drugs. The β-subunit of Mycobacterium tuberculosis (Mtb) RNAP (RpoB) interacts with an essential and global transcription factor, CarD, and confers antibiotic and oxidative stress resistance to Mtb. Compromising the RpoB/CarD interactions results in the killing of mycobacteria, hence disrupting the RpoB/CarD interaction has been proposed as a novel strategy for the development of anti-tubercular drugs. Here, we describe the first approach to rationally design and test the efficacy of the peptide-based inhibitors which specifically target the conserved PPI interface between the bacterial RNAP β/transcription factor complex. We performed in silico protein-peptide docking studies along with biochemical assays to characterize the novel peptide-based inhibitors. Our results suggest that the top ranked peptides are highly stable, soluble in aqueous buffer, and capable of inhibiting transcription with IC50 > 50 μM concentration. Using peptide-based molecules, our study provides the first piece of evidence to target the conserved RNAP β/transcription factor interface for designing new inhibitors. Our results may hence form the basis to further improve the potential of these novel peptides in modulating bacterial gene expression, thus inhibiting bacterial growth and combating bacterial infections.
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Affiliation(s)
- Gundeep Kaur
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India
| | - Srajan Kapoor
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India
| | - Soni Kaundal
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India
| | - Dipak Dutta
- Molecular Microbiology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India
| | - Krishan Gopal Thakur
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India
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11
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Brugger C, Zhang C, Suhanovsky MM, Kim DD, Sinclair AN, Lyumkis D, Deaconescu AM. Molecular determinants for dsDNA translocation by the transcription-repair coupling and evolvability factor Mfd. Nat Commun 2020; 11:3740. [PMID: 32719356 PMCID: PMC7385628 DOI: 10.1038/s41467-020-17457-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 07/01/2020] [Indexed: 11/15/2022] Open
Abstract
Mfd couples transcription to nucleotide excision repair, and acts on RNA polymerases when elongation is impeded. Depending on impediment severity, this action results in either transcription termination or elongation rescue, which rely on ATP-dependent Mfd translocation on DNA. Due to its role in antibiotic resistance, Mfd is also emerging as a prime target for developing anti-evolution drugs. Here we report the structure of DNA-bound Mfd, which reveals large DNA-induced structural changes that are linked to the active site via ATPase motif VI. These changes relieve autoinhibitory contacts between the N- and C-termini and unmask UvrA recognition determinants. We also demonstrate that translocation relies on a threonine in motif Ic, widely conserved in translocases, and a family-specific histidine near motif IVa, reminiscent of the “arginine clamp” of RNA helicases. Thus, Mfd employs a mode of DNA recognition that at its core is common to ss/ds translocases that act on DNA or RNA. Transcription-repair coupling factors (TRCFs) are large ATPases that mediate the preferential repair of the transcribed DNA strand. Here the authors reveal the cryo-EM structure of DNA-bound Mfd, the bacterial TRCF, and provide molecular insights into its mode of action.
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Affiliation(s)
- Christiane Brugger
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Cheng Zhang
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, 92093, USA
| | - Margaret M Suhanovsky
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - David D Kim
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Amy N Sinclair
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Dmitry Lyumkis
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, 92093, USA.,Department of Computational and Structural Biology, The Scripps Research Institute, La Jolla, CA, 92093, USA
| | - Alexandra M Deaconescu
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, 02903, USA.
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12
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Ho HN, van Oijen AM, Ghodke H. Single-molecule imaging reveals molecular coupling between transcription and DNA repair machinery in live cells. Nat Commun 2020; 11:1478. [PMID: 32198374 PMCID: PMC7083905 DOI: 10.1038/s41467-020-15182-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 02/23/2020] [Indexed: 01/20/2023] Open
Abstract
The Escherichia coli transcription-repair coupling factor Mfd displaces stalled RNA polymerase and delivers the stall site to the nucleotide excision repair factors UvrAB for damage detection. Whether this handoff from RNA polymerase to UvrA occurs via the Mfd-UvrA2-UvrB complex or alternate reaction intermediates in cells remains unclear. Here, we visualise Mfd in actively growing cells and determine the catalytic requirements for faithful recruitment of nucleotide excision repair proteins. We find that ATP hydrolysis by UvrA governs formation and disassembly of the Mfd-UvrA2 complex. Further, Mfd-UvrA2-UvrB complexes formed by UvrB mutants deficient in DNA loading and damage recognition are impaired in successful handoff. Our single-molecule dissection of interactions of Mfd with its partner proteins inside live cells shows that the dissociation of Mfd is tightly coupled to successful loading of UvrB, providing a mechanism via which loading of UvrB occurs in a strand-specific manner.
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Affiliation(s)
- Han Ngoc Ho
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
| | - Antoine M van Oijen
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
| | - Harshad Ghodke
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia.
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.
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13
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Strick TR, Portman JR. Transcription-Coupled Repair: From Cells to Single Molecules and Back Again. J Mol Biol 2019; 431:4093-4102. [PMID: 31175845 DOI: 10.1016/j.jmb.2019.05.040] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/20/2019] [Accepted: 05/23/2019] [Indexed: 11/19/2022]
Abstract
Transcription-coupled repair is mediated by the Mfd protein. TCR is defined as the preferential repair of DNA lesions in the transcribed strand of actively transcribed genes, and is opposed to the strand-aspecific global genome repair. The Mfd protein mediates TCR by binding to and displacing RNA polymerase, which is stalled at a DNA lesion on the transcribed strand of DNA, then recruiting UvrA and UvrB. The repair cascade results in the recruitment of, and DNA excision by, UvrC; removal of the damage-bearing oligonucleotide by UvrD; "filling-in" of the DNA by DNA polymerase; and sealing of the strands by DNA ligase. The gene required for Mfd was originally identified as a gene needed for the "mutation frequency decline" phenotype in which the repair of certain UV-induced lesions in the transcribed strand of tRNA genes is increased when cells are forced to delay replication immediately following UV exposure. This review will focus on the genetics that led to the discovery of the Mfd gene; summarize the subsequent biochemical, structural and single-molecule interrogations of the Mfd protein; and explore the more recent findings of Mfd in mutagenesis.
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Affiliation(s)
- T R Strick
- Institut Jacques Monod, CNRS and Université Paris 7, Paris Université, Paris, France; Institut de Biologie de l'Ecole normale supérieure, PSL Université, INSERM, CNRS, Paris, France; Equipe Labellisée de la Ligue Nationale Contre le Cancer, Paris, France; Horizons 2020 Innovative Training Network, DNAREPAIRMAN, Paris, France.
| | - J R Portman
- Institut Jacques Monod, CNRS and Université Paris 7, Paris Université, Paris, France; Institut de Biologie de l'Ecole normale supérieure, PSL Université, INSERM, CNRS, Paris, France; Horizons 2020 Innovative Training Network, DNAREPAIRMAN, Paris, France
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14
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Portman JR, Strick TR. Transcription-Coupled Repair and Complex Biology. J Mol Biol 2018; 430:4496-4512. [DOI: 10.1016/j.jmb.2018.04.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/23/2018] [Accepted: 04/23/2018] [Indexed: 10/24/2022]
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15
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The transcription-repair coupling factor Mfd associates with RNA polymerase in the absence of exogenous damage. Nat Commun 2018; 9:1570. [PMID: 29679003 PMCID: PMC5910403 DOI: 10.1038/s41467-018-03790-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 03/13/2018] [Indexed: 12/27/2022] Open
Abstract
During transcription elongation, bacterial RNA polymerase (RNAP) can pause, backtrack or stall when transcribing template DNA. Stalled transcription elongation complexes at sites of bulky lesions can be rescued by the transcription terminator Mfd. The molecular mechanisms of Mfd recruitment to transcription complexes in vivo remain to be elucidated, however. Using single-molecule live-cell imaging, we show that Mfd associates with elongation transcription complexes even in the absence of exogenous genotoxic stresses. This interaction requires an intact RNA polymerase-interacting domain of Mfd. In the presence of drugs that stall RNAP, we find that Mfd associates pervasively with RNAP. The residence time of Mfd foci reduces from 30 to 18 s in the presence of endogenous UvrA, suggesting that UvrA promotes the resolution of Mfd-RNAP complexes on DNA. Our results reveal that RNAP is frequently rescued by Mfd during normal growth and highlight a ubiquitous house-keeping role for Mfd in regulating transcription elongation.
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16
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Adebali O, Sancar A, Selby CP. Mfd translocase is necessary and sufficient for transcription-coupled repair in Escherichia coli. J Biol Chem 2017; 292:18386-18391. [PMID: 28986449 DOI: 10.1074/jbc.c117.818807] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/04/2017] [Indexed: 12/26/2022] Open
Abstract
Nucleotide excision repair in Escherichia coli is stimulated by transcription, specifically in the transcribed strand. Previously, it was shown that this transcription-coupled repair (TCR) is mediated by the Mfd translocase. Recently, it was proposed that in fact the majority of TCR in E. coli is catalyzed by a second pathway ("backtracking-mediated TCR") that is dependent on the UvrD helicase and the guanosine pentaphosphate (ppGpp) alarmone/stringent response regulator. Recently, we reported that as measured by the excision repair-sequencing (XR-seq), UvrD plays no role in TCR genome-wide. Here, we tested the role of ppGpp and UvrD in TCR genome-wide and in the lacZ operon using the XR-seq method, which directly measures repair. We found that the mfd mutation abolishes TCR genome-wide and in the lacZ operon. In contrast, the relA-spoT- mutant deficient in ppGpp synthesis carries out normal TCR. We conclude that UvrD and ppGpp play no role in TCR in E. coli.
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Affiliation(s)
- Ogun Adebali
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260
| | - Aziz Sancar
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260
| | - Christopher P Selby
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260
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17
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Selby CP. Mfd Protein and Transcription-Repair Coupling in Escherichia coli. Photochem Photobiol 2017; 93:280-295. [PMID: 27864884 DOI: 10.1111/php.12675] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/18/2016] [Indexed: 01/30/2023]
Abstract
In 1989, transcription-repair coupling (TRC) was first described in Escherichia coli, as the transcription-dependent, preferential nucleotide excision repair (NER) of UV photoproducts located in the template DNA strand. This finding led to pioneering biochemical studies of TRC in the laboratory of Professor Aziz Sancar, where, at the time, major contributions were being made toward understanding the roles of the UvrA, UvrB and UvrC proteins in NER. When the repair studies were extended to TRC, template but not coding strand lesions were found to block RNA polymerase (RNAP) in vitro, and unexpectedly, the blocked RNAP inhibited NER. A transcription-repair coupling factor, also called Mfd protein, was found to remove the blocked RNAP, deliver the repair enzyme to the lesion and thereby mediate more rapid repair of the transcription-blocking lesion compared with lesions elsewhere. Structural and functional analyses of Mfd protein revealed helicase motifs responsible for ATP hydrolysis and DNA binding, and regions that interact with RNAP and UvrA. These and additional studies provided a basis upon which other investigators, in following decades, have characterized fascinating and unexpected structural and mechanistic features of Mfd, revealed the possible existence of additional pathways of TRC and discovered additional roles of Mfd in the cell.
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Affiliation(s)
- Christopher P Selby
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC
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18
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Deaconescu AM, Suhanovsky MM. From Mfd to TRCF and Back Again-A Perspective on Bacterial Transcription-coupled Nucleotide Excision Repair. Photochem Photobiol 2017; 93:268-279. [PMID: 27859304 PMCID: PMC5672955 DOI: 10.1111/php.12661] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/08/2016] [Indexed: 12/17/2022]
Abstract
Photochemical and other reactions on DNA cause damage and corrupt genetic information. To counteract this damage, organisms have evolved intricate repair mechanisms that often crosstalk with other DNA-based processes such as transcription. Intriguing observations in the late 1980s and early 1990s led to the discovery of transcription-coupled repair (TCR), a subpathway of nucleotide excision repair. TCR, found in all domains of life, prioritizes for repair lesions located in the transcribed DNA strand, directly read by RNA polymerase. Here, we give a historical overview of developments in the field of bacterial TCR, starting from the pioneering work of Evelyn Witkin and Aziz Sancar, which led to the identification of the first transcription-repair coupling factor (the Mfd protein), to recent studies that have uncovered alternative TCR pathways and regulators.
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Affiliation(s)
- Alexandra M. Deaconescu
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02903, USA
| | - Margaret M. Suhanovsky
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02903, USA
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19
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Darrigo C, Guillemet E, Dervyn R, Ramarao N. The Bacterial Mfd Protein Prevents DNA Damage Induced by the Host Nitrogen Immune Response in a NER-Independent but RecBC-Dependent Pathway. PLoS One 2016; 11:e0163321. [PMID: 27711223 PMCID: PMC5053507 DOI: 10.1371/journal.pone.0163321] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 09/07/2016] [Indexed: 11/28/2022] Open
Abstract
Production of reactive nitrogen species is an important component of the host immune defence against bacteria. Here, we show that the bacterial protein Mfd (Mutation frequency decline), a highly conserved and ubiquitous bacterial protein involved in DNA repair, confers bacterial resistance to the eukaryotic nitrogen response produced by macrophage cells and during mice infection. In addition, we show that RecBC is also necessary to survive this stress. The inactivation of recBC and mfd genes is epistatic showing that Mfd follows the RecBC repair pathway to protect the bacteria against the genotoxic effect of nitrite. Surprisingly given the role of Mfd in transcription-coupled repair, UvrA is not necessary to survive the nitrite response. Taken together, our data reveal that during the eukaryotic nitrogen response, Mfd is required to maintain bacterial genome integrity in a NER-independent but RecBC-dependent pathway.
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Affiliation(s)
- Claire Darrigo
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Elisabeth Guillemet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Rozenn Dervyn
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Nalini Ramarao
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
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20
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Sancar A. Mechanisms of DNA Repair by Photolyase and Excision Nuclease (Nobel Lecture). Angew Chem Int Ed Engl 2016; 55:8502-27. [PMID: 27337655 DOI: 10.1002/anie.201601524] [Citation(s) in RCA: 177] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Indexed: 01/27/2023]
Abstract
Ultraviolet light damages DNA by converting two adjacent thymines into a thymine dimer which is potentially mutagenic, carcinogenic, or lethal to the organism. This damage is repaired by photolyase and the nucleotide excision repair system in E. coli by nucleotide excision repair in humans. The work leading to these results is presented by Aziz Sancar in his Nobel Lecture.
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Affiliation(s)
- Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA.
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21
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Sancar A. Mechanismen der DNA-Reparatur durch Photolyasen und Exzisionsnukleasen (Nobel-Aufsatz). Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201601524] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Aziz Sancar
- Department of Biochemistry and Biophysics; University of North Carolina School of Medicine; Chapel Hill North Carolina USA
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22
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Li W, Selvam K, Rahman SA, Li S. Sen1, the yeast homolog of human senataxin, plays a more direct role than Rad26 in transcription coupled DNA repair. Nucleic Acids Res 2016; 44:6794-802. [PMID: 27179024 PMCID: PMC5001595 DOI: 10.1093/nar/gkw428] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 05/05/2016] [Indexed: 11/13/2022] Open
Abstract
Rad26, a DNA dependent ATPase that is homologous to human CSB, has been well known to play an important role in transcription coupled DNA repair (TCR) in the yeast Saccharomyces cerevisiae Sen1, a DNA/RNA helicase that is essential for yeast cell viability and homologous to human senataxin, has been known to be required for transcriptional termination of short noncoding RNA genes and for a fail-safe transcriptional termination mechanism of protein-coding genes. Sen1 has also been shown to protect the yeast genome from transcription-associated recombination by resolving RNA:DNA hybrids naturally formed during transcription. Here, we show that the N-terminal non-essential region of Sen1 plays an important role in TCR, whereas the C-terminal nonessential region and the helicase activity of Sen1 are largely dispensable for the repair. Unlike Rad26, which becomes completely dispensable for TCR in cells lacking the TCR repressor Spt4, Sen1 is still required for efficient TCR in the absence of Spt4. Also unlike Rad26, which is important for repair at many but not all damaged sites in the transcribed strand of a gene, Sen1 is required for efficient repair at essentially all the damaged sites. Our results indicate that Sen1 plays a more direct role than Rad26 in TCR.
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Affiliation(s)
- Wentao Li
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Kathiresan Selvam
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Sheikh A Rahman
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Shisheng Li
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
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23
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Van Houten B. A tale of two cities: A tribute to Aziz Sancar's Nobel Prize in Chemistry for his molecular characterization of NER. DNA Repair (Amst) 2016; 37:A3-A13. [PMID: 26861185 PMCID: PMC5068483 DOI: 10.1016/j.dnarep.2015.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Bennett Van Houten
- Department of Pharmacology and Chemical Biology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, United States.
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24
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Abstract
Bacteria lack subcellular compartments and harbor a single RNA polymerase that synthesizes both structural and protein-coding RNAs, which are cotranscriptionally processed by distinct pathways. Nascent rRNAs fold into elaborate secondary structures and associate with ribosomal proteins, whereas nascent mRNAs are translated by ribosomes. During elongation, nucleic acid signals and regulatory proteins modulate concurrent RNA-processing events, instruct RNA polymerase where to pause and terminate transcription, or act as roadblocks to the moving enzyme. Communications among complexes that carry out transcription, translation, repair, and other cellular processes ensure timely execution of the gene expression program and survival under conditions of stress. This network is maintained by auxiliary proteins that act as bridges between RNA polymerase, ribosome, and repair enzymes, blurring boundaries between separate information-processing steps and making assignments of unique regulatory functions meaningless. Understanding the regulation of transcript elongation thus requires genome-wide approaches, which confirm known and reveal new regulatory connections.
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Affiliation(s)
| | - Irina Artsimovitch
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210;
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25
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A dynamic DNA-repair complex observed by correlative single-molecule nanomanipulation and fluorescence. Nat Struct Mol Biol 2015; 22:452-7. [PMID: 25961799 DOI: 10.1038/nsmb.3019] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 04/03/2015] [Indexed: 01/20/2023]
Abstract
We characterize in real time the composition and catalytic state of the initial Escherichia coli transcription-coupled repair (TCR) machinery by using correlative single-molecule methods. TCR initiates when RNA polymerase (RNAP) stalled by a lesion is displaced by the Mfd DNA translocase, thus giving repair components access to the damage. We previously used DNA nanomanipulation to obtain a nanomechanical readout of protein-DNA interactions during TCR initiation. Here we correlate this signal with simultaneous single-molecule fluorescence imaging of labeled components (RNAP, Mfd or RNA) to monitor the composition and localization of the complex. Displacement of stalled RNAP by Mfd results in loss of nascent RNA but not of RNAP, which remains associated with Mfd as a long-lived complex on the DNA. This complex translocates at ∼4 bp/s along the DNA, in a manner determined by the orientation of the stalled RNAP on the DNA.
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26
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Kamarthapu V, Nudler E. Rethinking transcription coupled DNA repair. Curr Opin Microbiol 2015; 24:15-20. [PMID: 25596348 DOI: 10.1016/j.mib.2014.12.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/22/2014] [Accepted: 12/30/2014] [Indexed: 11/26/2022]
Abstract
Nucleotide excision repair (NER) is an evolutionarily conserved, multistep process that can detect a wide variety of DNA lesions. Transcription coupled repair (TCR) is a subpathway of NER that repairs the transcribed DNA strand faster than the rest of the genome. RNA polymerase (RNAP) stalled at DNA lesions mediates the recruitment of NER enzymes to the damage site. In this review we focus on a newly identified bacterial TCR pathway in which the NER enzyme UvrD, in conjunction with NusA, plays a major role in initiating the repair process. We discuss the tradeoff between the new and conventional models of TCR, how and when each pathway operates to repair DNA damage, and the necessity of pervasive transcription in maintaining genome integrity.
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Affiliation(s)
- Venu Kamarthapu
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA.
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27
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Li W, Selvam K, Ko T, Li S. Transcription bypass of DNA lesions enhances cell survival but attenuates transcription coupled DNA repair. Nucleic Acids Res 2014; 42:13242-53. [PMID: 25389266 PMCID: PMC4245964 DOI: 10.1093/nar/gku1150] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Transcription-coupled DNA repair (TCR) is a subpathway of nucleotide excision repair (NER) dedicated to rapid removal of DNA lesions in the transcribed strand of actively transcribed genes. The precise nature of the TCR signal and how the repair machinery gains access to lesions imbedded in stalled RNA polymerase II (RNAP II) complexes in eukaryotic cells are still enigmatic. RNAP II has an intrinsic capacity for transcription bypass of DNA lesions by incorporation or misincorporation of nucleotides across the lesions. It has been suggested that transcription bypass of lesions, which exposes the lesions, may be required for TCR. Here, we show that E1103G mutation of Rpb1, the largest subunit of RNAP II, which promotes transcription bypass of UV-induced cyclobutane pyrimidine dimers (CPDs), increases survival of UV irradiated yeast cells but attenuates TCR. The increased cell survival is independent of any NER subpathways. In contrast, G730D mutation of Rpb1, which impairs transcription bypass of CPDs, enhances TCR. Our results suggest that transcription bypass of lesions attenuates TCR but enhances cell tolerance to DNA lesions. Efficient stalling of RNAP II is essential for efficient TCR.
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Affiliation(s)
- Wentao Li
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Kathiresan Selvam
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Tengyu Ko
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Shisheng Li
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
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28
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Epshtein V. UvrD helicase: an old dog with a new trick: how one step backward leads to many steps forward. Bioessays 2014; 37:12-9. [PMID: 25345862 DOI: 10.1002/bies.201400106] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Transcription-coupled repair (TCR) is a phenomenon that exists in a wide variety of organisms from bacteria to humans. This mechanism allows cells to repair the actively transcribed DNA strand much faster than the non-transcribed one. At the sites of bulky DNA damage RNA polymerase stalls, initiating recruitment of the repair machinery. It is a commonly accepted paradigm that bacterial cells utilize a sole coupling factor, called Mfd to initiate TCR. According to that model, Mfd removes transcription complexes stalled at the lesion site and simultaneously recruits repair machinery. However, this model was recently put in doubt by various discrepancies between the proposed universal role of Mfd in the TCR and its biochemical and phenotypical properties. Here, I present a second pathway of bacterial TCR recently discovered in my laboratory, which does not involve Mfd but implicates a common repair factor, UvrD, in a central position in the process.
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Affiliation(s)
- Vitaliy Epshtein
- Department of Biochemistry, New York University, Langhorn Medical Center, New York, NY, USA
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29
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Savery N. Prioritizing the repair of DNA damage that is encountered by RNA polymerase. Transcription 2014; 2:168-172. [PMID: 21922058 DOI: 10.4161/trns.2.4.16146] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Revised: 05/12/2011] [Accepted: 05/13/2011] [Indexed: 11/19/2022] Open
Abstract
Transcription-coupled DNA repair pathways enable lesions that block transcription to be repaired more quickly than similar lesions in other parts of the genome. Here I consider the recent progress that has been made in understanding how bacteria prioritize certain lesions for nucleotide excision repair.
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Affiliation(s)
- Nigel Savery
- DNA-Protein Interactions Unit; School of Biochemistry; University of Bristol; Bristol, UK
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30
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Hao N, Krishna S, Ahlgren-Berg A, Cutts EE, Shearwin KE, Dodd IB. Road rules for traffic on DNA-systematic analysis of transcriptional roadblocking in vivo. Nucleic Acids Res 2014; 42:8861-72. [PMID: 25034688 PMCID: PMC4132739 DOI: 10.1093/nar/gku627] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Genomic DNA is bound by many proteins that could potentially impede elongation of RNA polymerase (RNAP), but the factors determining the magnitude of transcriptional roadblocking in vivo are poorly understood. Through systematic experiments and modeling, we analyse how roadblocking by the lac repressor (LacI) in Escherichia coli cells is controlled by promoter firing rate, the concentration and affinity of the roadblocker protein, the transcription-coupled repair protein Mfd, and promoter–roadblock spacing. Increased readthrough of the roadblock at higher RNAP fluxes requires active dislodgement of LacI by multiple RNAPs. However, this RNAP cooperation effect occurs only for strong promoters because roadblock-paused RNAP is quickly terminated by Mfd. The results are most consistent with a single RNAP also sometimes dislodging LacI, though we cannot exclude the possibility that a single RNAP reads through by waiting for spontaneous LacI dissociation. Reducing the occupancy of the roadblock site by increasing the LacI off-rate (weakening the operator) increased dislodgement strongly, giving a stronger effect on readthrough than decreasing the LacI on-rate (decreasing LacI concentration). Thus, protein binding kinetics can be tuned to maintain site occupation while reducing detrimental roadblocking.
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Affiliation(s)
- Nan Hao
- School of Molecular and Biomedical Sciences (Biochemistry), The University of Adelaide, Adelaide, SA 5005, Australia
| | - Sandeep Krishna
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Bangalore 560065, India
| | - Alexandra Ahlgren-Berg
- School of Molecular and Biomedical Sciences (Biochemistry), The University of Adelaide, Adelaide, SA 5005, Australia
| | - Erin E Cutts
- School of Molecular and Biomedical Sciences (Biochemistry), The University of Adelaide, Adelaide, SA 5005, Australia
| | - Keith E Shearwin
- School of Molecular and Biomedical Sciences (Biochemistry), The University of Adelaide, Adelaide, SA 5005, Australia
| | - Ian B Dodd
- School of Molecular and Biomedical Sciences (Biochemistry), The University of Adelaide, Adelaide, SA 5005, Australia
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31
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Abstract
A quarter of a century has elapsed since the discovery of transcription-coupled repair (TCR), and yet our fascination with this process has not diminished. Nucleotide excision repair (NER) is a versatile pathway that removes helix-distorting DNA lesions from the genomes of organisms across the evolutionary scale, from bacteria to humans. TCR, defined as a subpathway of NER, is dedicated to the repair of lesions that, by virtue of their location on the transcribed strands of active genes, encumber elongation by RNA polymerases. In this review, we will report on newly identified proteins, protein modifications, and protein complexes that participate in TCR in Escherichia coli and in human cells. We will discuss general models for the biochemical pathways and how and when cells might choose to utilize TCR or other pathways for repair or bypass of transcription-blocking DNA alterations.
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Affiliation(s)
- Graciela Spivak
- Biology Department, Stanford University, 385 Serra Mall, Stanford, CA 94305-5020, USA.
| | - Ann K Ganesan
- Biology Department, Stanford University, 385 Serra Mall, Stanford, CA 94305-5020, USA.
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32
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Howan K, Monnet J, Fan J, Strick TR. Stopped in its tracks: the RNA polymerase molecular motor as a robust sensor of DNA damage. DNA Repair (Amst) 2014; 20:49-57. [PMID: 24685770 DOI: 10.1016/j.dnarep.2014.02.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 02/25/2014] [Accepted: 02/26/2014] [Indexed: 10/25/2022]
Abstract
DNA repair is often a complex, multi-component, multi-step process; this makes detailed kinetic analysis of the different steps of repair a challenging task using standard biochemical methods. At the same time, single-molecule methods are well-suited for extracting kinetic information despite time-averaging due to diffusion of biochemical components and stochasticity of chemical reaction steps. Here we discuss recent experiments using DNA nanomanipulation in a magnetic trap to study the initiation of transcription-coupled repair in a model bacterial system comprising the canonical Escherichia coli RNA polymerase and the Mfd translocase which specifically binds to it. These experiments provide kinetic insight into the reaction process, helping to explain how Mfd discriminates between transcribing RNAP and stalled RNAP. They also identify a reliably long-lived intermediate containing Mfd translocase and, potentially, RNA polymerase. This intermediate presumably serves as a platform for assembly of downstream repair components UvrAB(C).
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Affiliation(s)
- K Howan
- Institut Jacques Monod, CNRS, UMR7592, University Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France
| | - J Monnet
- Institut Jacques Monod, CNRS, UMR7592, University Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France
| | - J Fan
- Institut Jacques Monod, CNRS, UMR7592, University Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France
| | - T R Strick
- Institut Jacques Monod, CNRS, UMR7592, University Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France.
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Deaconescu AM. RNA polymerase between lesion bypass and DNA repair. Cell Mol Life Sci 2013; 70:4495-509. [PMID: 23807206 PMCID: PMC11113250 DOI: 10.1007/s00018-013-1384-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Revised: 05/13/2013] [Accepted: 05/23/2013] [Indexed: 11/29/2022]
Abstract
DNA damage leads to heritable changes in the genome via DNA replication. However, as the DNA helix is the site of numerous other transactions, notably transcription, DNA damage can have diverse repercussions on cellular physiology. In particular, DNA lesions have distinct effects on the passage of transcribing RNA polymerases, from easy bypass to almost complete block of transcription elongation. The fate of the RNA polymerase positioned at a lesion is largely determined by whether the lesion is structurally subtle and can be accommodated and eventually bypassed, or bulky, structurally distorting and requiring remodeling/complete dissociation of the transcription elongation complex, excision, and repair. Here we review cellular responses to DNA damage that involve RNA polymerases with a focus on bacterial transcription-coupled nucleotide excision repair and lesion bypass via transcriptional mutagenesis. Emphasis is placed on the explosion of new structural information on RNA polymerases and relevant DNA repair factors and the mechanistic models derived from it.
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Affiliation(s)
- Alexandra M Deaconescu
- Rosenstiel Basic Medical Sciences Research Center, Brandeis University, 415 South St., MS029, Waltham, MA, 02454, USA,
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Rad26, the transcription-coupled repair factor in yeast, is required for removal of stalled RNA polymerase-II following UV irradiation. PLoS One 2013; 8:e72090. [PMID: 23991048 PMCID: PMC3749123 DOI: 10.1371/journal.pone.0072090] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 07/07/2013] [Indexed: 11/29/2022] Open
Abstract
Transcription coupled nucleotide excision repair (TCR) is a major pathway responsible for removal of helix distorting DNA lesions from transcriptionally active regions of the genome. Rad26, a key factor of the TCR pathway, is known to play a role during early steps of TCR. Here, we show that Rad26-mediated TCR is not absolutely dependent on active transcription elongation in budding yeast. As per our results, RAD26-deleted cells show enhanced UV sensitivity compared to wild type cells under conditions where transcription elongation is inhibited. The increased UV sensitivity observed in RAD26-deleted cells, however, is not due to reduced expression of the major NER-responsive genes. Interestingly, transcription of the constitutively expressed RPB2 gene is adversely affected in RAD26-deleted cells during UV-induced DNA damage repair. In consonance, chromatin immunoprecipitation analysis showed that unlike in wild type, in RAD26-deleted cells no significant reduction in RNA polymerase II occupancy occurs during nucleotide excision repair in the transcriptionally active loci like, RPB2, PYK1 and RPL2B. These results collectively indicate that removal of RNAPII during DNA damage repair following UV irradiation is dependent on Rad26.
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Cho I, Tsai PF, Lake RJ, Basheer A, Fan HY. ATP-dependent chromatin remodeling by Cockayne syndrome protein B and NAP1-like histone chaperones is required for efficient transcription-coupled DNA repair. PLoS Genet 2013; 9:e1003407. [PMID: 23637612 PMCID: PMC3630089 DOI: 10.1371/journal.pgen.1003407] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Accepted: 02/07/2013] [Indexed: 11/19/2022] Open
Abstract
The Cockayne syndrome complementation group B (CSB) protein is essential for transcription-coupled DNA repair, and mutations in CSB are associated with Cockayne syndrome—a devastating disease with complex clinical features, including the appearance of premature aging, sun sensitivity, and numerous neurological and developmental defects. CSB belongs to the SWI2/SNF2 ATP–dependent chromatin remodeler family, but the extent to which CSB remodels chromatin and whether this activity is utilized in DNA repair is unknown. Here, we show that CSB repositions nucleosomes in an ATP–dependent manner in vitro and that this activity is greatly enhanced by the NAP1-like histone chaperones, which we identify as new CSB–binding partners. By mapping functional domains and analyzing CSB derivatives, we demonstrate that chromatin remodeling by the combined activities of CSB and the NAP1-like chaperones is required for efficient transcription-coupled DNA repair. Moreover, we show that chromatin remodeling and repair protein recruitment mediated by CSB are separable activities. The collaboration that we observed between CSB and the NAP1-like histone chaperones adds a new dimension to our understanding of the ways in which ATP–dependent chromatin remodelers and histone chaperones can regulate chromatin structure. Taken together, the results of this study offer new insights into the functions of chromatin remodeling by CSB in transcription-coupled DNA repair as well as the underlying mechanisms of Cockayne syndrome. Cockayne syndrome is a devastating inherited disease; the average life span of those afflicted is 12 years. Cockayne syndrome patients have features of premature aging, are highly sensitive to sunlight, and suffer from numerous developmental and neurological disorders. The majority of Cockayne syndrome patients have mutations in the CSB protein; however, how these mutations can lead to Cockayne syndrome is largely unknown. CSB is essential for transcription-coupled DNA repair—a process that preferentially removes bulky DNA lesions that stall transcription, such as those created by ultraviolet light. In eukaryotes, DNA is packaged into nucleosomes, which consists of DNA wrapped around a set of core histone proteins, and nucleosomes can create barriers to the DNA repair process. In this study, we found that CSB can slide histones along DNA. We also found that histone chaperones, proteins that accept and donate histones, greatly facilitate this process. Importantly, we show that CSB derivatives that are unable to move nucleosomes or collaborate with histone chaperones cannot repair UV-induced DNA lesions. Our study reveals that nucleosome remodeling by CSB is important for transcription-coupled DNA repair and suggests that an inability to efficiently mobilize nucleosomes might contribute to the underlying mechanism of Cockayne syndrome.
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Affiliation(s)
- Iltaeg Cho
- Epigenetics Program, Department of Biochemistry and Biophysics, Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Pei-Fang Tsai
- Epigenetics Program, Department of Biochemistry and Biophysics, Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Robert J. Lake
- Epigenetics Program, Department of Biochemistry and Biophysics, Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Asjad Basheer
- Epigenetics Program, Department of Biochemistry and Biophysics, Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Hua-Ying Fan
- Epigenetics Program, Department of Biochemistry and Biophysics, Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Lake RJ, Fan HY. Structure, function and regulation of CSB: a multi-talented gymnast. Mech Ageing Dev 2013; 134:202-11. [PMID: 23422418 DOI: 10.1016/j.mad.2013.02.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 01/26/2013] [Accepted: 02/08/2013] [Indexed: 11/29/2022]
Abstract
The Cockayne syndrome complementation group B protein, CSB, plays pivotal roles in transcription regulation and DNA repair. CSB belongs to the SNF2/SWI2 ATP-dependent chromatin remodeling protein family, and studies from many laboratories have revealed that CSB has multiple activities and modes of regulation. To understand the underlying mechanisms of Cockayne syndrome, it is necessary to understand how the biochemical activities of CSB are used to carry out its biological functions. In this review, we summarize our current knowledge of the structure, function and regulation of CSB, and discuss how these properties can impact the biological functions of this chromatin remodeler.
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Affiliation(s)
- Robert J Lake
- Epigenetics Program, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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37
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Couvé S, Ishchenko AA, Fedorova OS, Ramanculov EM, Laval J, Saparbaev M. Direct DNA Lesion Reversal and Excision Repair in Escherichia coli. EcoSal Plus 2013; 5. [PMID: 26442931 DOI: 10.1128/ecosalplus.7.2.4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Indexed: 06/05/2023]
Abstract
Cellular DNA is constantly challenged by various endogenous and exogenous genotoxic factors that inevitably lead to DNA damage: structural and chemical modifications of primary DNA sequence. These DNA lesions are either cytotoxic, because they block DNA replication and transcription, or mutagenic due to the miscoding nature of the DNA modifications, or both, and are believed to contribute to cell lethality and mutagenesis. Studies on DNA repair in Escherichia coli spearheaded formulation of principal strategies to counteract DNA damage and mutagenesis, such as: direct lesion reversal, DNA excision repair, mismatch and recombinational repair and genotoxic stress signalling pathways. These DNA repair pathways are universal among cellular organisms. Mechanistic principles used for each repair strategies are fundamentally different. Direct lesion reversal removes DNA damage without need for excision and de novo DNA synthesis, whereas DNA excision repair that includes pathways such as base excision, nucleotide excision, alternative excision and mismatch repair, proceeds through phosphodiester bond breakage, de novo DNA synthesis and ligation. Cell signalling systems, such as adaptive and oxidative stress responses, although not DNA repair pathways per se, are nevertheless essential to counteract DNA damage and mutagenesis. The present review focuses on the nature of DNA damage, direct lesion reversal, DNA excision repair pathways and adaptive and oxidative stress responses in E. coli.
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Deaconescu AM, Artsimovitch I, Grigorieff N. Interplay of DNA repair with transcription: from structures to mechanisms. Trends Biochem Sci 2012; 37:543-52. [PMID: 23084398 DOI: 10.1016/j.tibs.2012.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 09/10/2012] [Accepted: 09/14/2012] [Indexed: 01/29/2023]
Abstract
Many DNA transactions are crucial for maintaining genomic integrity and faithful transfer of genetic information but remain poorly understood. An example is the interplay between nucleotide excision repair (NER) and transcription, also known as transcription-coupled DNA repair (TCR). Discovered decades ago, the mechanisms for TCR have remained elusive, not in small part due to the scarcity of structural studies of key players. Here we summarize recent structural information on NER/TCR factors, focusing on bacterial systems, and integrate it with existing genetic, biochemical, and biophysical data to delineate the mechanisms at play. We also review emerging, alternative modalities for recruitment of NER proteins to DNA lesions.
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Affiliation(s)
- Alexandra M Deaconescu
- Howard Hughes Medical Institute, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, 415 South St., MS 029, Waltham, MA 02454, USA.
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Nucleotide excision repair (NER) machinery recruitment by the transcription-repair coupling factor involves unmasking of a conserved intramolecular interface. Proc Natl Acad Sci U S A 2012; 109:3353-8. [PMID: 22331906 DOI: 10.1073/pnas.1115105109] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Transcription-coupled DNA repair targets DNA lesions that block progression of elongating RNA polymerases. In bacteria, the transcription-repair coupling factor (TRCF; also known as Mfd) SF2 ATPase recognizes RNA polymerase stalled at a site of DNA damage, removes the enzyme from the DNA, and recruits the Uvr(A)BC nucleotide excision repair machinery via UvrA binding. Previous studies of TRCF revealed a molecular architecture incompatible with UvrA binding, leaving its recruitment mechanism unclear. Here, we examine the UvrA recognition determinants of TRCF using X-ray crystallography of a core TRCF-UvrA complex and probe the conformational flexibility of TRCF in the absence and presence of nucleotides using small-angle X-ray scattering. We demonstrate that the C-terminal domain of TRCF is inhibitory for UvrA binding, but not RNA polymerase release, and show that nucleotide binding induces concerted multidomain motions. Our studies suggest that autoinhibition of UvrA binding in TRCF may be relieved only upon engaging the DNA damage.
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40
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Ganesan A, Spivak G, Hanawalt PC. Transcription-coupled DNA repair in prokaryotes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 110:25-40. [PMID: 22749141 DOI: 10.1016/b978-0-12-387665-2.00002-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Transcription-coupled repair (TCR) is a subpathway of nucleotide excision repair (NER) that acts specifically on lesions in the transcribed strand of expressed genes. First reported in mammalian cells, TCR was then documented in Escherichia coli. In this organism, an RNA polymerase arrested at a lesion is displaced by the transcription repair coupling factor, Mfd. This protein recruits the NER lesion-recognition factor UvrA, and then dissociates from the DNA. UvrA binds UvrB, and the assembled UvrAB* complex initiates repair. In mutants lacking active Mfd, TCR is absent. A gene transcribed by the bacteriophage T7 RNA polymerase in E. coli also requires Mfd for TCR. The CSB protein (missing or defective in cells of patients with Cockayne syndrome, complementation group B) is essential for TCR in humans. CSB and its homologs in higher eukaryotes are likely functional equivalents of Mfd.
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Affiliation(s)
- Ann Ganesan
- Department of Biology, Stanford University, Stanford, California, USA
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41
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Belitsky BR, Sonenshein AL. Roadblock repression of transcription by Bacillus subtilis CodY. J Mol Biol 2011; 411:729-43. [PMID: 21699902 DOI: 10.1016/j.jmb.2011.06.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2011] [Revised: 06/04/2011] [Accepted: 06/07/2011] [Indexed: 11/25/2022]
Abstract
CodY is a global transcriptional regulator that is known to control, directly or indirectly, expression of more than 100 genes and operons in Bacillus subtilis. Using a combination of mutational analysis and DNase I footprinting experiments, we identified two high-affinity CodY-binding sites that contribute to repression of the ybgE gene and appear to act independently. One of these sites, located 80 bp downstream of the transcription start site, accounted for the bulk of ybgE repression. Using in vitro transcription experiments, we demonstrated that in the presence of CodY, a shorter-than-expected ybgE transcript that terminates at the downstream CodY-binding site was synthesized. Thus, CodY binding to the downstream site represses transcription by a roadblock mechanism. Similar premature termination of transcription was observed for bcaP and yufN, two other CodY-regulated genes with binding sites downstream of the promoter. In accord with the roadblock mechanism, CodY-mediated repression at downstream sites was partly relieved if the transcription-repair coupling factor Mfd was inactivated.
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Affiliation(s)
- Boris R Belitsky
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA.
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42
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Prabha S, Rao DN, Nagaraja V. Distinct properties of hexameric but functionally conserved Mycobacterium tuberculosis transcription-repair coupling factor. PLoS One 2011; 6:e19131. [PMID: 21559463 PMCID: PMC3084762 DOI: 10.1371/journal.pone.0019131] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 03/17/2011] [Indexed: 12/04/2022] Open
Abstract
Transcription coupled nucleotide excision repair (TC-NER) is involved in correcting UV-induced damage and other road-blocks encountered in the transcribed strand. Mutation frequency decline (Mfd) is a transcription repair coupling factor, involved in repair of template strand during transcription. Mfd from M. tuberculosis (MtbMfd) is 1234 amino-acids long harboring characteristic modules for different activities. Mtbmfd complemented Escherichia coli mfd (Ecomfd) deficient strain, enhanced survival of UV irradiated cells and increased the road-block repression in vivo. The protein exhibited ATPase activity, which was stimulated ∼1.5-fold in the presence of DNA. While the C-terminal domain (CTD) comprising amino acids 630 to 1234 showed ∼2-fold elevated ATPase activity than MtbMfd, the N-terminal domain (NTD) containing the first 433 amino acid residues was able to bind ATP but deficient in hydrolysis. Overexpression of NTD of MtbMfd led to growth defect and hypersensitivity to UV light. Deletion of 184 amino acids from the C-terminal end of MtbMfd (MfdΔC) increased the ATPase activity by ∼10-fold and correspondingly exhibited efficient translocation along DNA as compared to the MtbMfd and CTD. Surprisingly, MtbMfd was found to be distributed in monomer and hexamer forms both in vivo and in vitro and the monomer showed increased susceptibility to proteases compared to the hexamer. MfdΔC, on the other hand, was predominantly monomeric in solution implicating the extreme C-terminal region in oligomerization of the protein. Thus, although the MtbMfd resembles EcoMfd in many of its reaction characteristics, some of its hitherto unknown distinct properties hint at its species specific role in mycobacteria during transcription-coupled repair.
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Affiliation(s)
- Swayam Prabha
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Desirazu N. Rao
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
- * E-mail: (DNR); (VN)
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
- * E-mail: (DNR); (VN)
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43
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Manelyte L, Kim YIT, Smith AJ, Smith RM, Savery NJ. Regulation and rate enhancement during transcription-coupled DNA repair. Mol Cell 2011; 40:714-24. [PMID: 21145481 PMCID: PMC3025350 DOI: 10.1016/j.molcel.2010.11.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 08/03/2010] [Accepted: 09/14/2010] [Indexed: 11/22/2022]
Abstract
Transcription-coupled DNA repair (TCR) is a subpathway of nucleotide excision repair (NER) that is triggered when RNA polymerase is stalled by DNA damage. Lesions targeted by TCR are repaired more quickly than lesions repaired by the transcription-independent “global” NER pathway, but the mechanism underlying this rate enhancement is not understood. Damage recognition during bacterial NER depends upon UvrA, which binds to the damage and loads UvrB onto the DNA. Bacterial TCR additionally requires the Mfd protein, a DNA translocase that removes the stalled transcription complexes. We have determined the properties of Mfd, UvrA, and UvrB that are required for the elevated rate of repair observed during TCR. We show that TCR and global NER differ in their requirements for damage recognition by UvrA, indicating that Mfd acts at the very earliest stage of the repair process and extending the functional similarities between TCR in bacteria and eukaryotes.
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Affiliation(s)
- Laura Manelyte
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
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44
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Kuo HK, Krasich R, Bhagwat AS, Kreuzer KN. Importance of the tmRNA system for cell survival when transcription is blocked by DNA-protein cross-links. Mol Microbiol 2010; 78:686-700. [PMID: 20807197 DOI: 10.1111/j.1365-2958.2010.07355.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Anticancer drug 5-azacytidine (aza-C) induces DNA-protein cross-links (DPCs) between cytosine methyltransferase and DNA as the drug inhibits methylation. We found that mutants defective in the tmRNA translational quality control system are hypersensitive to aza-C. Hypersensitivity requires expression of active methyltransferase, indicating the importance of DPC formation. Furthermore, the tmRNA pathway is activated upon aza-C treatment in cells expressing methyltransferase, resulting in increased levels of SsrA tagged proteins. These results argue that the tmRNA pathway clears stalled ribosome-mRNA complexes generated after transcriptional blockage by aza-C-induced DPCs. In support, an ssrA mutant is also hypersensitive to streptolydigin, which blocks RNA polymerase elongation by a different mechanism. The tmRNA pathway is thought to act only on ribosomes containing a 3' RNA end near the A site, and the known pathway for releasing RNA 3' ends from a blocked polymerase involves Mfd helicase. However, an mfd knockout mutant is not hypersensitive to either aza-C-induced DPC formation or streptolydigin, indicating that Mfd is not involved. Transcription termination factor Rho is also likely not involved, because the Rho-specific inhibitor bicyclomycin failed to show synergism with either aza-C or streptolydigin. Based on these findings, we discuss models for how E. coli processes transcription/translation complexes blocked at DPCs.
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Affiliation(s)
- H Kenny Kuo
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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45
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Ganesan AK, Hanawalt PC. Transcription-coupled nucleotide excision repair of a gene transcribed by bacteriophage T7 RNA polymerase in Escherichia coli. DNA Repair (Amst) 2010; 9:958-63. [PMID: 20638914 DOI: 10.1016/j.dnarep.2010.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 05/28/2010] [Accepted: 06/22/2010] [Indexed: 11/17/2022]
Abstract
Transcription-coupled nucleotide excision repair (TC-NER) removes certain kinds of lesions from the transcribed strand of expressed genes. The signal for TC-NER is thought to be RNA polymerase stalled at a lesion in the DNA template. In Escherichia coli, the stalled polymerase is dissociated from the lesion by the transcription repair coupling factor (Mfd protein), which also recruits excision repair proteins to the site resulting in efficient removal of the lesion. TC-NER has been documented in cells from a variety of organisms ranging from bacteria to humans. In each case, the RNA polymerase involved has been a multimeric protein complex. To ascertain whether a gene transcribed by the monomeric RNA polymerase of bacteriophage T7 could be repaired by TC-NER, we constructed strains of E. coli in which the chromosomal lacZ gene is controlled by a T7 promoter. In the absence of T7 RNA polymerase, little or no beta-galactosidase is produced, indicating that the E. coli RNA polymerase does not transcribe lacZ efficiently, if at all, in these strains. By introducing a plasmid (pAR1219) carrying the T7 gene 1 under control of the E. coli lac UV5 promoter into these strains, we obtained derivatives in which the level of T7 RNA polymerase could be regulated. In cultures containing upregulated levels of the polymerase, beta-galactosidase was actively produced indicating that the T7 RNA polymerase transcribes the lacZ gene efficiently. Under these conditions, we observed that UV-induced cyclobutane pyrimidine dimers were removed more rapidly from the transcribed strand of lacZ than from the nontranscribed strand, supporting the conclusion that TC-NER occurred in this gene. This response was absent in an mfd-1 mutant, indicating that the underlying mechanism may be similar to that for the bacterial RNA polymerase.
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Affiliation(s)
- Ann K Ganesan
- Department of Biology, Stanford University, Stanford, CA 94305-5020, USA.
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46
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Savery NJ. The molecular mechanism of transcription-coupled DNA repair. Trends Microbiol 2007; 15:326-33. [PMID: 17572090 DOI: 10.1016/j.tim.2007.05.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Revised: 04/11/2007] [Accepted: 05/25/2007] [Indexed: 02/04/2023]
Abstract
DNA damage that blocks the transcription of genes is prioritized for repair by transcription-coupled DNA repair pathways. RNA polymerases stalled at DNA lesions obstruct repair enzymes, but this situation is turned to the advantage of the cell by transcription-repair coupling factors that remove the stalled RNA polymerase from DNA and increase the rate at which the lesion is repaired. Recent structural studies of the bacterial transcription-repair coupling factor, Mfd, have revealed a modular architecture in which an ATP-dependent DNA-based motor is coupled to protein-protein interaction domains that can attach the motor to RNA polymerase and the DNA repair protein UvrA. Here I review the key features of this multifunctional protein and discuss how recent mechanistic and structural findings have advanced our understanding of transcription-coupled DNA repair in bacteria.
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Affiliation(s)
- Nigel J Savery
- DNA-Protein Interactions Unit, Department of Biochemistry, University of Bristol, Bristol BS8 1TD, UK.
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47
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Ganesan AK, Smith AJ, Savery NJ, Zamos P, Hanawalt PC. Transcription coupled nucleotide excision repair in Escherichia coli can be affected by changing the arginine at position 529 of the beta subunit of RNA polymerase. DNA Repair (Amst) 2007; 6:1434-40. [PMID: 17532270 PMCID: PMC2578841 DOI: 10.1016/j.dnarep.2007.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Revised: 04/04/2007] [Accepted: 04/05/2007] [Indexed: 11/25/2022]
Abstract
The proposed mechanism for transcription coupled nucleotide excision repair (TCR) invokes RNA polymerase (RNAP) blocked at a DNA lesion as a signal to initiate repair. In Escherichia coli, TCR requires the interaction of RNAP with a transcription-repair coupling factor encoded by the mfd gene. The interaction between RNAP and Mfd depends upon amino acids 117, 118, and 119 of the beta subunit of RNAP; changing any one of these to alanine diminishes the interaction [1]. Using direct assays for TCR, and the lac operon of E. coli containing UV induced cyclobutane pyrimidine dimers (CPDs) as substrate, we have found that a change from arginine to cysteine at amino acid 529 of the beta subunit of the RNAP inactivates TCR, but does not prevent the interaction of RNAP with Mfd. Our results suggest that this interaction may be necessary but not sufficient to facilitate TCR.
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Affiliation(s)
- Ann K Ganesan
- Department of Biological Sciences, Stanford University, Stanford, CA 94303-5020, USA.
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48
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Pitsikas P, Lee D, Rainbow AJ. Reduced host cell reactivation of oxidative DNA damage in human cells deficient in the mismatch repair gene hMSH2. Mutagenesis 2007; 22:235-43. [PMID: 17351251 DOI: 10.1093/mutage/gem008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Germ line mutations in the mismatch repair (MMR) genes hMSH2 and hMLH1 account for approximately 98% of hereditary non-polyposis colorectal cancers. In addition, there is increasing evidence for an involvement of MMR gene expression in the response of cells to UV-induced skin cancer. The link between MMR and skin cancer suggests an involvement of MMR gene expression in the response of skin cells to UV-induced DNA damage. In this report, we have used two reporter gene assays to examine the role of hMSH2 and hMLH1 in the repair of oxidative DNA damage induced by UVA light and DNA damage caused by methylene blue plus visible light (MB+VL). UVA and MB+VL produce 8-hydroxyguanines in DNA that are repaired by base excision repair (BER). AdHCMVlacZ is a replication-deficient recombinant adenovirus that expresses the beta-galactosidase (beta-gal) reporter gene under the control of the human cytomegalovirus (CMV) immediate-early promoter. We show a reduced host cell reactivation for beta-gal expression of UVA-treated and MB+VL-treated AdHCMVlacZ in hMSH2-deficient LoVo human colon adenocarcinoma cells compared to their hMSH2-proficient counterpart SW480 cells, but not in hMLH1-deficient HCT116 human colon adenocarcinoma cells compared to hMLH1-proficient HCT116-chr3 cells. We have also reported previously that enhanced expression of the undamaged AdHCMVlacZ reporter gene is induced by the pre-treatment of cells with lower levels of the DNA-damaging agent and to higher expression levels in transcription-coupled repair (TCR)-deficient compared to TCR-proficient cells. Here we show that pre-treatment of cells with UVA or MB+VL enhanced expression of the undamaged reporter gene to a higher level in LoVo compared to SW480 cells but there was little or no difference in HCT116 compared to HCT116-chr3 cells. These results suggest a substantial involvement of hMSH2 but little or no involvement of hMLH1 in the repair of UVA- and MB+VL-induced oxidative DNA damage by BER.
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Affiliation(s)
- Photini Pitsikas
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
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Deaconescu AM, Savery N, Darst SA. The bacterial transcription repair coupling factor. Curr Opin Struct Biol 2007; 17:96-102. [PMID: 17239578 PMCID: PMC2757452 DOI: 10.1016/j.sbi.2007.01.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2006] [Revised: 11/27/2006] [Accepted: 01/10/2007] [Indexed: 10/23/2022]
Abstract
The widely conserved bacterial transcription repair coupling factor (TRCF) is a large, multidomain, superfamily 2 ATPase. It couples nucleotide excision repair with transcription by dislodging inactive RNA polymerase molecules stalled at template DNA lesions and increasing the rate at which the Uvr(A)BC excinuclease acts at these sites. The recent elucidation of X-ray crystal structures of Escherichia coli TRCF revealed its architectural details, and will enable the design of more incisive experiments addressing how TRCF translocates on double-stranded DNA, destabilizes the RNA polymerase ternary elongation complex and recruits the Uvr(A)BC system.
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Affiliation(s)
| | - Nigel Savery
- Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK.
| | - Seth A. Darst
- Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
- Corresponding author: Darst, Seth A. ()
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Saxowsky TT, Doetsch PW. RNA polymerase encounters with DNA damage: transcription-coupled repair or transcriptional mutagenesis? Chem Rev 2006; 106:474-88. [PMID: 16464015 DOI: 10.1021/cr040466q] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Tina T Saxowsky
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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