1
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Pedraza-Reyes M, Abundiz-Yañez K, Rangel-Mendoza A, Martínez LE, Barajas-Ornelas RC, Cuéllar-Cruz M, Leyva-Sánchez HC, Ayala-García VM, Valenzuela-García LI, Robleto EA. Bacillus subtilis stress-associated mutagenesis and developmental DNA repair. Microbiol Mol Biol Rev 2024; 88:e0015823. [PMID: 38551349 PMCID: PMC11332352 DOI: 10.1128/mmbr.00158-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024] Open
Abstract
SUMMARYThe metabolic conditions that prevail during bacterial growth have evolved with the faithful operation of repair systems that recognize and eliminate DNA lesions caused by intracellular and exogenous agents. This idea is supported by the low rate of spontaneous mutations (10-9) that occur in replicating cells, maintaining genome integrity. In contrast, when growth and/or replication cease, bacteria frequently process DNA lesions in an error-prone manner. DNA repairs provide cells with the tools needed for maintaining homeostasis during stressful conditions and depend on the developmental context in which repair events occur. Thus, different physiological scenarios can be anticipated. In nutritionally stressed bacteria, different components of the base excision repair pathway may process damaged DNA in an error-prone approach, promoting genetic variability. Interestingly, suppressing the mismatch repair machinery and activating specific DNA glycosylases promote stationary-phase mutations. Current evidence also suggests that in resting cells, coupling repair processes to actively transcribed genes may promote multiple genetic transactions that are advantageous for stressed cells. DNA repair during sporulation is of interest as a model to understand how transcriptional processes influence the formation of mutations in conditions where replication is halted. Current reports indicate that transcriptional coupling repair-dependent and -independent processes operate in differentiating cells to process spontaneous and induced DNA damage and that error-prone synthesis of DNA is involved in these events. These and other noncanonical ways of DNA repair that contribute to mutagenesis, survival, and evolution are reviewed in this manuscript.
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Affiliation(s)
- Mario Pedraza-Reyes
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, Guanajuato, Mexico
| | - Karen Abundiz-Yañez
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, Guanajuato, Mexico
| | - Alejandra Rangel-Mendoza
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, Guanajuato, Mexico
| | - Lissett E. Martínez
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, Guanajuato, Mexico
| | - Rocío C. Barajas-Ornelas
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, Guanajuato, Mexico
| | - Mayra Cuéllar-Cruz
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, Guanajuato, Mexico
| | | | | | - Luz I. Valenzuela-García
- Department of Sustainable Engineering, Advanced Materials Research Center (CIMAV), Arroyo Seco, Durango, Mexico
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2
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Smith EL, Goley ED. House of CarDs: Functional insights into the transcriptional regulator CdnL. Mol Microbiol 2024. [PMID: 38664995 DOI: 10.1111/mmi.15268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/12/2024] [Accepted: 04/11/2024] [Indexed: 07/07/2024]
Abstract
Regulation of bacterial transcription is a complex and multi-faceted phenomenon that is critical for growth and adaptation. Proteins in the CarD_CdnL_TRCF family are widespread, often essential, regulators of transcription of genes required for growth and metabolic homeostasis. Research in the last decade has described the mechanistic and structural bases of CarD-CdnL-mediated regulation of transcription initiation. More recently, studies in a range of bacteria have begun to elucidate the physiological roles of CarD-CdnL proteins as well as mechanisms by which these proteins, themselves, are regulated. A theme has emerged wherein regulation of CarD-CdnL proteins is central to bacterial adaptation to stress and/or changing environmental conditions.
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Affiliation(s)
- Erika L Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Erin D Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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3
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Carvajal-Garcia J, Bracey H, Johnson AE, Hernandez Viera AJ, Egli M, Simsek EN, Jaremba EA, Kim K, Merrikh H. A small molecule that inhibits the evolution of antibiotic resistance. NAR MOLECULAR MEDICINE 2024; 1:ugae001. [PMID: 38911259 PMCID: PMC11188740 DOI: 10.1093/narmme/ugae001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/11/2023] [Accepted: 01/04/2024] [Indexed: 06/25/2024]
Abstract
Antibiotic resistance rapidly develops against almost all available therapeutics. Therefore, searching for new antibiotics to overcome the problem of antibiotic resistance alone is insufficient. Given that antibiotic resistance can be driven by mutagenesis, an avenue for preventing it is the inhibition of mutagenic processes. We previously showed that the DNA translocase Mfd is mutagenic and accelerates antibiotic resistance development. Here, we present our discovery of a small molecule that inhibits Mfd-dependent mutagenesis, ARM-1 (anti-resistance molecule 1). We found ARM-1 using a high-throughput, small molecule, in vivo screen. Using biochemical assays, we characterized the mechanism by which ARM-1 inhibits Mfd. Critically, we found that ARM-1 reduces mutagenesis and significantly delays antibiotic resistance development across highly divergent bacterial pathogens. These results demonstrate that the mutagenic proteins accelerating evolution can be directly inhibited. Furthermore, our findings suggest that Mfd inhibition, alongside antibiotics, is a potentially effective approach for prevention of antibiotic resistance development during treatment of infections.
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Affiliation(s)
| | - Harrison Bracey
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Anna E Johnson
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | | | - Martin Egli
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Esra N Simsek
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Emily A Jaremba
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Kwangho Kim
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Houra Merrikh
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
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4
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Wang L, Watters JW, Ju X, Lu G, Liu S. Head-on and co-directional RNA polymerase collisions orchestrate bidirectional transcription termination. Mol Cell 2023; 83:1153-1164.e4. [PMID: 36917983 PMCID: PMC10081963 DOI: 10.1016/j.molcel.2023.02.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 01/03/2023] [Accepted: 02/15/2023] [Indexed: 03/14/2023]
Abstract
Genomic DNA is a crowded track where motor proteins frequently collide. It remains underexplored whether these collisions carry physiological function. In this work, we develop a single-molecule assay to visualize the trafficking of individual E. coli RNA polymerases (RNAPs) on DNA. Based on transcriptomic data, we hypothesize that RNAP collisions drive bidirectional transcription termination of convergent gene pairs. Single-molecule results show that the head-on collision between two converging RNAPs is necessary to prevent transcriptional readthrough but insufficient to release the RNAPs from the DNA. Remarkably, co-directional collision of a trailing RNAP into the head-on collided complex dramatically increases the termination efficiency. Furthermore, stem-loop structures formed in the nascent RNA are required for collisions to occur at well-defined positions between convergent genes. These findings suggest that physical collisions between RNAPs furnish a mechanism for transcription termination and that programmed genomic conflicts can be exploited to co-regulate the expression of multiple genes.
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Affiliation(s)
- Ling Wang
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA.
| | - John W Watters
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Xiangwu Ju
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Genzhe Lu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA.
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5
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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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6
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Zeitler L, Denby Wilkes C, Goldar A, Soutourina J. A quantitative modelling approach for DNA repair on a population scale. PLoS Comput Biol 2022; 18:e1010488. [PMID: 36094963 PMCID: PMC9499311 DOI: 10.1371/journal.pcbi.1010488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 09/22/2022] [Accepted: 08/12/2022] [Indexed: 11/18/2022] Open
Abstract
The great advances of sequencing technologies allow the in vivo measurement of nuclear processes-such as DNA repair after UV exposure-over entire cell populations. However, data sets usually contain only a few samples over several hours, missing possibly important information in between time points. We developed a data-driven approach to analyse CPD repair kinetics over time in Saccharomyces cerevisiae. In contrast to other studies that consider sequencing signals as an average behaviour, we understand them as the superposition of signals from independent cells. By motivating repair as a stochastic process, we derive a minimal model for which the parameters can be conveniently estimated. We correlate repair parameters to a variety of genomic features that are assumed to influence repair, including transcription rate and nucleosome density. The clearest link was found for the transcription unit length, which has been unreported for budding yeast to our knowledge. The framework hence allows a comprehensive analysis of nuclear processes on a population scale.
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Affiliation(s)
- Leo Zeitler
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Cyril Denby Wilkes
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Arach Goldar
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Julie Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
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7
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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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8
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Carrasco B, Moreno-del Álamo M, Torres R, Alonso JC. PcrA Dissociates RecA Filaments and the SsbA and RecO Mediators Counterbalance Such Activity. Front Mol Biosci 2022; 9:836211. [PMID: 35223992 PMCID: PMC8865920 DOI: 10.3389/fmolb.2022.836211] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/05/2022] [Indexed: 11/24/2022] Open
Abstract
PcrA depletion is lethal in wild-type Bacillus subtilis cells. The PcrA DNA helicase contributes to unwinding RNA from the template strand, backtracking the RNA polymerase, rescuing replication-transcription conflicts, and disassembling RecA from single-stranded DNA (ssDNA) by poorly understood mechanisms. We show that, in the presence of RecA, circa one PcrA/plasmid-size circular ssDNA (cssDNA) molecule hydrolyzes ATP at a rate similar to that on the isolated cssDNA. PcrA K37A, which poorly hydrolyses ATP, fails to displace RecA from cssDNA. SsbA inhibits and blocks the ATPase activities of PcrA and RecA, respectively. RecO partially antagonizes and counteracts the negative effect of SsbA on PcrA- and RecA-mediated ATP hydrolysis, respectively. Conversely, multiple PcrA molecules are required to inhibit RecA·ATP-mediated DNA strand exchange (DSE). RecO and SsbA poorly antagonize the PcrA inhibitory effect on RecA·ATP-mediated DSE. We propose that two separable PcrA functions exist: an iterative translocating PcrA monomer strips RecA from cssDNA to prevent unnecessary recombination with the mediators SsbA and RecO balancing such activity; and a PcrA cluster that disrupts DNA transactions, as RecA-mediated DSE.
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9
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Gong P. Within and Beyond the Nucleotide Addition Cycle of Viral RNA-dependent RNA Polymerases. Front Mol Biosci 2022; 8:822218. [PMID: 35083282 PMCID: PMC8784604 DOI: 10.3389/fmolb.2021.822218] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 12/21/2021] [Indexed: 11/13/2022] Open
Abstract
Nucleotide addition cycle (NAC) is a fundamental process utilized by nucleic acid polymerases when carrying out nucleic acid biosynthesis. An induced-fit mechanism is usually taken by these polymerases upon NTP/dNTP substrate binding, leading to active site closure and formation of a phosphodiester bond. In viral RNA-dependent RNA polymerases, the post-chemistry translocation is stringently controlled by a structurally conserved motif, resulting in asymmetric movement of the template-product duplex. This perspective focuses on viral RdRP NAC and related mechanisms that have not been structurally clarified to date. Firstly, RdRP movement along the template strand in the absence of catalytic events may be relevant to catalytic complex dissociation or proofreading. Secondly, pyrophosphate or non-cognate NTP-mediated cleavage of the product strand 3′-nucleotide can also play a role in reactivating paused or arrested catalytic complexes. Furthermore, non-cognate NTP substrates, including NTP analog inhibitors, can not only alter NAC when being misincorporated, but also impact on subsequent NACs. Complications and challenges related to these topics are also discussed.
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Affiliation(s)
- Peng Gong
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
- Drug Discovery Center for Infectious Diseases, Nankai University, Tianjin, China
- *Correspondence: Peng Gong,
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10
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Abstract
Methods for detecting and dissecting the interactions of virally encoded proteins are essential for probing basic viral biology and providing a foundation for therapeutic advances. The dearth of targeted therapeutics for the treatment of coronavirus disease 2019 (COVID-19), an ongoing global health crisis, underscores the importance of gaining a deeper understanding of the interactions of proteins encoded by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we describe the use of a convenient bacterial cell-based two-hybrid (B2H) system to analyze the SARS-CoV-2 proteome. We identified 16 distinct intraviral protein-protein interactions (PPIs), involving 16 proteins. We found that many of the identified proteins interact with more than one partner. Further, our system facilitates the genetic dissection of these interactions, enabling the identification of selectively disruptive mutations. We also describe a modified B2H system that permits the detection of disulfide bond-dependent PPIs in the normally reducing Escherichia coli cytoplasm, and we used this system to detect the interaction of the SARS-CoV-2 spike protein receptor-binding domain (RBD) with its cognate cell surface receptor ACE2. We then examined how the RBD-ACE2 interaction is perturbed by several RBD amino acid substitutions found in currently circulating SARS-CoV-2 variants. Our findings illustrate the utility of a genetically tractable bacterial system for probing the interactions of viral proteins and investigating the effects of emerging mutations. In principle, the system could also facilitate the identification of potential therapeutics that disrupt specific interactions of virally encoded proteins. More generally, our findings establish the feasibility of using a B2H system to detect and dissect disulfide bond-dependent interactions of eukaryotic proteins.
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11
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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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12
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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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13
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Interactome Analysis of KIN (Kin17) Shows New Functions of This Protein. Curr Issues Mol Biol 2021; 43:767-781. [PMID: 34449532 PMCID: PMC8929021 DOI: 10.3390/cimb43020056] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/16/2021] [Accepted: 06/24/2021] [Indexed: 11/16/2022] Open
Abstract
KIN (Kin17) protein is overexpressed in a number of cancerous cell lines, and is therefore considered a possible cancer biomarker. It is a well-conserved protein across eukaryotes and is ubiquitously expressed in all cell types studied, suggesting an important role in the maintenance of basic cellular function which is yet to be well determined. Early studies on KIN suggested that this nuclear protein plays a role in cellular mechanisms such as DNA replication and/or repair; however, its association with chromatin depends on its methylation state. In order to provide a better understanding of the cellular role of this protein, we investigated its interactome by proximity-dependent biotin identification coupled to mass spectrometry (BioID-MS), used for identification of protein-protein interactions. Our analyses detected interaction with a novel set of proteins and reinforced previous observations linking KIN to factors involved in RNA processing, notably pre-mRNA splicing and ribosome biogenesis. However, little evidence supports that this protein is directly coupled to DNA replication and/or repair processes, as previously suggested. Furthermore, a novel interaction was observed with PRMT7 (protein arginine methyltransferase 7) and we demonstrated that KIN is modified by this enzyme. This interactome analysis indicates that KIN is associated with several cell metabolism functions, and shows for the first time an association with ribosome biogenesis, suggesting that KIN is likely a moonlight protein.
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14
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Urrutia-Irazabal I, Ault JR, Sobott F, Savery NJ, Dillingham MS. Analysis of the PcrA-RNA polymerase complex reveals a helicase interaction motif and a role for PcrA/UvrD helicase in the suppression of R-loops. eLife 2021; 10:68829. [PMID: 34279225 PMCID: PMC8318588 DOI: 10.7554/elife.68829] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/16/2021] [Indexed: 12/12/2022] Open
Abstract
The PcrA/UvrD helicase binds directly to RNA polymerase (RNAP) but the structural basis for this interaction and its functional significance have remained unclear. In this work, we used biochemical assays and hydrogen-deuterium exchange coupled to mass spectrometry to study the PcrA-RNAP complex. We find that PcrA binds tightly to a transcription elongation complex in a manner dependent on protein:protein interaction with the conserved PcrA C-terminal Tudor domain. The helicase binds predominantly to two positions on the surface of RNAP. The PcrA C-terminal domain engages a conserved region in a lineage-specific insert within the β subunit which we identify as a helicase interaction motif present in many other PcrA partner proteins, including the nucleotide excision repair factor UvrB. The catalytic core of the helicase binds near the RNA and DNA exit channels and blocking PcrA activity in vivo leads to the accumulation of R-loops. We propose a role for PcrA as an R-loop suppression factor that helps to minimize conflicts between transcription and other processes on DNA including replication.
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Affiliation(s)
- Inigo Urrutia-Irazabal
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol. Biomedical Sciences Building, University Walk, Bristol, United Kingdom
| | - James R Ault
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Frank Sobott
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Nigel J Savery
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol. Biomedical Sciences Building, University Walk, Bristol, United Kingdom
| | - Mark S Dillingham
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol. Biomedical Sciences Building, University Walk, Bristol, United Kingdom
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15
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Kawale AA, Burmann BM. Inherent backbone dynamics fine-tune the functional plasticity of Tudor domains. Structure 2021; 29:1253-1265.e4. [PMID: 34197736 DOI: 10.1016/j.str.2021.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 04/19/2021] [Accepted: 06/04/2021] [Indexed: 10/21/2022]
Abstract
Tudor domains are crucial for mediating a diversity of protein-protein or protein-DNA interactions involved in nucleic acid metabolism. Using solution NMR spectroscopy, we assess the comprehensive understanding of the dynamical properties of the respective Tudor domains from four different bacterial (Escherichia coli) proteins UvrD, Mfd, RfaH, and NusG involved in different aspects of bacterial transcription regulation and associated processes. These proteins are benchmarked to the canonical Tudor domain fold from the human SMN protein. The detailed analysis of protein backbone dynamics and subsequent analysis by the Lipari-Szabo model-free approach revealed subtle differences in motions of the amide-bond vector on both pico- to nanosecond and micro- to millisecond timescales. On these timescales, our comparative approach reveals the usefulness of discrete amplitudes of dynamics to discern the different functionalities for Tudor domains exhibiting promiscuous binding, including the metamorphic Tudor domain included in the study.
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Affiliation(s)
- Ashish A Kawale
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 40530 Gothenburg, Sweden; Department of Chemistry and Molecular Biology, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Björn M Burmann
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 40530 Gothenburg, Sweden; Department of Chemistry and Molecular Biology, University of Gothenburg, 40530 Gothenburg, Sweden.
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16
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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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17
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Mfd regulates RNA polymerase association with hard-to-transcribe regions in vivo, especially those with structured RNAs. Proc Natl Acad Sci U S A 2021; 118:2008498118. [PMID: 33443179 DOI: 10.1073/pnas.2008498118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
RNA polymerase (RNAP) encounters various roadblocks during transcription. These obstacles can impede RNAP movement and influence transcription, ultimately necessitating the activity of RNAP-associated factors. One such factor is the bacterial protein Mfd, a highly conserved DNA translocase and evolvability factor that interacts with RNAP. Although Mfd is thought to function primarily in the repair of DNA lesions that stall RNAP, increasing evidence suggests that it may also be important for transcription regulation. However, this is yet to be fully characterized. To shed light on Mfd's in vivo functions, we identified the chromosomal regions where it associates. We analyzed Mfd's impact on RNAP association and transcription regulation genome-wide. We found that Mfd represses RNAP association at many chromosomal regions. We found that these regions show increased RNAP pausing, suggesting that they are hard to transcribe. Interestingly, we noticed that the majority of the regions where Mfd regulates transcription contain highly structured regulatory RNAs. The RNAs identified regulate a myriad of biological processes, ranging from metabolism to transfer RNA regulation to toxin-antitoxin (TA) functions. We found that cells lacking Mfd are highly sensitive to toxin overexpression. Finally, we found that Mfd promotes mutagenesis in at least one toxin gene, suggesting that its function in regulating transcription may promote evolution of certain TA systems and other regions containing strong RNA secondary structures. We conclude that Mfd is an RNAP cofactor that is important, and at times critical, for transcription regulation at hard-to-transcribe regions, especially those that express structured regulatory RNAs.
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18
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Abstract
R-loops are nucleic acid hybrids which form when an RNA invades duplex DNA to pair with its template sequence. Although they are implicated in a growing number of gene regulatory processes, their mechanistic origins remain unclear. We here report real-time observations of cotranscriptional R-loop formation at single-molecule resolution and propose a mechanism for their formation. We show that the bacterial Mfd protein can simultaneously interact with both elongating RNA polymerase and upstream DNA, tethering the two together and partitioning the DNA into distinct supercoiled domains. A highly negatively supercoiled domain forms in between Mfd and RNA polymerase, and compensatory positive supercoiling appears in front of the RNA polymerase and behind Mfd. The nascent RNA invades the negatively supercoiled domain and forms a stable R-loop that can drive mutagenesis. This mechanism theoretically enables any protein that simultaneously binds an actively translocating RNA polymerase and upstream DNA to stimulate R-loop formation.
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19
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The Role of Replication Clamp-Loader Protein HolC of Escherichia coli in Overcoming Replication/Transcription Conflicts. mBio 2021; 12:mBio.00184-21. [PMID: 33688004 PMCID: PMC8092217 DOI: 10.1128/mbio.00184-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Escherichia coli, DNA replication is catalyzed by an assembly of proteins, the DNA polymerase III holoenzyme. This complex includes the polymerase and proofreading subunits, the processivity clamp, and clamp loader complex. The holC gene encodes an accessory protein (known as χ) to the core clamp loader complex and is the only protein of the holoenzyme that binds to single-strand DNA binding protein, SSB. HolC is not essential for viability, although mutants show growth impairment, genetic instability, and sensitivity to DNA damaging agents. In this study, we isolate spontaneous suppressor mutants in a ΔholC strain and identify these by whole-genome sequencing. Some suppressors are alleles of RNA polymerase, suggesting that transcription is problematic for holC mutant strains, or alleles of sspA, encoding stringent starvation protein. Using a conditional holC plasmid, we examine factors affecting transcription elongation and termination for synergistic or suppressive effects on holC mutant phenotypes. Alleles of RpoA (α), RpoB (β), and RpoC (β') RNA polymerase holoenzyme can partially suppress loss of HolC. In contrast, mutations in transcription factors DksA and NusA enhanced the inviability of holC mutants. HolC mutants showed enhanced sensitivity to bicyclomycin, a specific inhibitor of Rho-dependent termination. Bicyclomycin also reverses suppression of holC by rpoA, rpoC, and sspA An inversion of the highly expressed rrnA operon exacerbates the growth defects of holC mutants. We propose that transcription complexes block replication in holC mutants and that Rho-dependent transcriptional termination and DksA function are particularly important to sustain viability and chromosome integrity.IMPORTANCE Transcription elongation complexes present an impediment to DNA replication. We provide evidence that one component of the replication clamp loader complex, HolC, of Escherichia coli is required to overcome these blocks. This genetic study of transcription factor effects on holC growth defects implicates Rho-dependent transcriptional termination and DksA function as critical. It also implicates, for the first time, a role of SspA, stringent starvation protein, in avoidance or tolerance of replication/replication conflicts. We speculate that HolC helps avoid or resolve collisions between replication and transcription complexes, which become toxic in HolC's absence.
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20
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Shi J, Wen A, Zhao M, Jin S, You L, Shi Y, Dong S, Hua X, Zhang Y, Feng Y. Structural basis of Mfd-dependent transcription termination. Nucleic Acids Res 2021; 48:11762-11772. [PMID: 33068413 PMCID: PMC7672476 DOI: 10.1093/nar/gkaa904] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/26/2020] [Accepted: 10/01/2020] [Indexed: 11/16/2022] Open
Abstract
Mfd-dependent transcription termination plays an important role in transcription-coupled DNA repair, transcription-replication conflict resolution, and antimicrobial resistance development. Despite extensive studies, the molecular mechanism of Mfd-dependent transcription termination in bacteria remains unclear, with several long-standing puzzles. How Mfd is activated by stalled RNA polymerase (RNAP) and how activated Mfd translocates along the DNA are unknown. Here, we report the single-particle cryo-electron microscopy structures of T. thermophilus Mfd-RNAP complex with and without ATPγS. The structures reveal that Mfd undergoes profound conformational changes upon activation, contacts the RNAP β1 domain and its clamp, and pries open the RNAP clamp. These structures provide a foundation for future studies aimed at dissecting the precise mechanism of Mfd-dependent transcription termination and pave the way for rational drug design targeting Mfd for the purpose of tackling the antimicrobial resistance crisis.
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Affiliation(s)
- Jing Shi
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Pathology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Zhejiang Provincial Key Laboratory of Immunity and Inflammatory diseases, Hangzhou 310058, China
| | - Aijia Wen
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Minxing Zhao
- Department of Emergency Medicine of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Sha Jin
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Linlin You
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yue Shi
- Department of Pathology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Shuling Dong
- School of Chemistry and Life Sciences, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Xiaoting Hua
- Department of Infectious Disease, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou 310058, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yu Feng
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Pathology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Zhejiang Provincial Key Laboratory of Immunity and Inflammatory diseases, Hangzhou 310058, China
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21
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Han S, Gong Z, Liang T, Chen Y, Xie J. The role of Mfd in Mycobacterium tuberculosis physiology and underlying regulatory network. Microbiol Res 2021; 246:126718. [PMID: 33588338 DOI: 10.1016/j.micres.2021.126718] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 01/18/2021] [Accepted: 01/26/2021] [Indexed: 12/23/2022]
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis with millions of deaths annually, remains one of the most formidable pathogen to global public health. As the most successful intracellular pathogens, Mtb can spatiotemporally coordinate the transcription and translation timely to reconcile the inevitable transcription-replication conflicts. Mutation frequency decline (Mfd) is a bacterial ATP-dependent DNA translocase that couples DNA repair to transcription via hydrolyzing ATP as energy, which preferentially acts on the damaged DNA transcribed strand to rescue stalled RNAP or dissociate RNAP to terminate the transcription depending on impediment severity, mitigating the damage to bacteria. In addition to the traditional damage repair effect, Mfd may also promote bacteria mutagenesis under stresses and boost the drug resistance. Mfd is widespread among bacteria and intensively studied, but there are very few studies in Mycobacteria, especially Mtb. In this review, the structure, function and mechanism characteristics of Mfd in Mtb (MtbMfd, Rv1020) are explored, with emphasis on the regulatory network of MtbMfd and its potential as a prime target for antibiotic drugs against tuberculosis.
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Affiliation(s)
- Shuang Han
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing, 400715, China
| | - Zhen Gong
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing, 400715, China
| | - Tian Liang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing, 400715, China
| | - Yu Chen
- Department of Tuberculosis, Shenyang Tenth People's Hospital and Shenyang Chest Hospital, Shenyang, Liaoning Province, 110044, China.
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing, 400715, China.
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22
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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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23
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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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24
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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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25
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Kawale AA, Burmann BM. UvrD helicase-RNA polymerase interactions are governed by UvrD's carboxy-terminal Tudor domain. Commun Biol 2020; 3:607. [PMID: 33097771 PMCID: PMC7585439 DOI: 10.1038/s42003-020-01332-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 09/28/2020] [Indexed: 12/12/2022] Open
Abstract
All living organisms have to cope with the constant threat of genome damage by UV light and other toxic reagents. To maintain the integrity of their genomes, organisms developed a variety of DNA repair pathways. One of these, the Transcription Coupled DNA-Repair (TCR) pathway, is triggered by stalled RNA Polymerase (RNAP) complexes at DNA damage sites on actively transcribed genes. A recently elucidated bacterial TCR pathway employs the UvrD helicase pulling back stalled RNAP complexes from the damage, stimulating recruitment of the DNA-repair machinery. However, structural and functional aspects of UvrD's interaction with RNA Polymerase remain elusive. Here we used advanced solution NMR spectroscopy to investigate UvrD's role within the TCR, identifying that the carboxy-terminal region of the UvrD helicase facilitates RNAP interactions by adopting a Tudor-domain like fold. Subsequently, we functionally analyzed this domain, identifying it as a crucial component for the UvrD-RNAP interaction besides having nucleic-acid affinity.
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Affiliation(s)
- Ashish A Kawale
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, 40530, Sweden
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, 40530, Sweden
| | - Björn M Burmann
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, 40530, Sweden.
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, 40530, Sweden.
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26
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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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27
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Pandey S, Gravel CM, Stockert OM, Wang CD, Hegner CL, LeBlanc H, Berry KE. Genetic identification of the functional surface for RNA binding by Escherichia coli ProQ. Nucleic Acids Res 2020; 48:4507-4520. [PMID: 32170306 PMCID: PMC7192607 DOI: 10.1093/nar/gkaa144] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/20/2020] [Accepted: 02/24/2020] [Indexed: 12/17/2022] Open
Abstract
The FinO-domain-protein ProQ is an RNA-binding protein that has been known to play a role in osmoregulation in proteobacteria. Recently, ProQ has been shown to act as a global RNA-binding protein in Salmonella and Escherichia coli, binding to dozens of small RNAs (sRNAs) and messenger RNAs (mRNAs) to regulate mRNA-expression levels through interactions with both 5′ and 3′ untranslated regions (UTRs). Despite excitement around ProQ as a novel global RNA-binding protein, and its potential to serve as a matchmaking RNA chaperone, significant gaps remain in our understanding of the molecular mechanisms ProQ uses to interact with RNA. In order to apply the tools of molecular genetics to this question, we have adapted a bacterial three-hybrid (B3H) assay to detect ProQ’s interactions with target RNAs. Using domain truncations, site-directed mutagenesis and an unbiased forward genetic screen, we have identified a group of highly conserved residues on ProQ’s NTD as the primary face for in vivo recognition of two RNAs, and propose that the NTD structure serves as an electrostatic scaffold to recognize the shape of an RNA duplex.
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Affiliation(s)
- Smriti Pandey
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Chandra M Gravel
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Oliver M Stockert
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Clara D Wang
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Courtney L Hegner
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Hannah LeBlanc
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Katherine E Berry
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA.,Department of Chemistry, Mount Holyoke College, South Hadley, MA 01075, USA
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28
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Moreno-Del Alamo M, Torres R, Manfredi C, Ruiz-Masó JA, Del Solar G, Alonso JC. Bacillus subtilis PcrA Couples DNA Replication, Transcription, Recombination and Segregation. Front Mol Biosci 2020; 7:140. [PMID: 32793628 PMCID: PMC7385302 DOI: 10.3389/fmolb.2020.00140] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/10/2020] [Indexed: 01/08/2023] Open
Abstract
Bacillus subtilis PcrA abrogates replication-transcription conflicts in vivo and disrupts RecA nucleoprotein filaments in vitro. Inactivation of pcrA is lethal. We show that PcrA depletion lethality is suppressed by recJ (involved in end resection), recA (the recombinase), or mfd (transcription-coupled repair) inactivation, but not by inactivating end resection (addAB or recQ), positive and negative RecA modulators (rarA or recX and recU), or genes involved in the reactivation of a stalled RNA polymerase (recD2, helD, hepA, and ywqA). We also report that B. subtilis mutations previously designated as recL16 actually map to the recO locus, and confirm that PcrA depletion lethality is suppressed by recO inactivation. The pcrA gene is epistatic to recA or mfd, but it is not epistatic to addAB, recJ, recQ, recO16, rarA, recX, recU, recD2, helD, hepA, or ywqA in response to DNA damage. PcrA depletion led to the accumulation of unsegregated chromosomes, and this defect is increased by recQ, rarA, or recU inactivation. We propose that PcrA, which is crucial to maintain cell viability, is involved in different DNA transactions.
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Affiliation(s)
- María Moreno-Del Alamo
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, Madrid, Spain
| | - Rubén Torres
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, Madrid, Spain
| | - Candela Manfredi
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, Madrid, Spain
| | - José A Ruiz-Masó
- Centro de Investigaciones Biológicas Margarita Salas, CIB-CSIC, Madrid, Spain
| | - Gloria Del Solar
- Centro de Investigaciones Biológicas Margarita Salas, CIB-CSIC, Madrid, Spain
| | - Juan Carlos Alonso
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, Madrid, Spain
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29
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Agapov A, Ignatov A, Turtola M, Belogurov G, Esyunina D, Kulbachinskiy A. Role of the trigger loop in translesion RNA synthesis by bacterial RNA polymerase. J Biol Chem 2020; 295:9583-9595. [PMID: 32439804 DOI: 10.1074/jbc.ra119.011844] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 05/20/2020] [Indexed: 11/06/2022] Open
Abstract
DNA lesions can severely compromise transcription and block RNA synthesis by RNA polymerase (RNAP), leading to subsequent recruitment of DNA repair factors to the stalled transcription complex. Recent structural studies have uncovered molecular interactions of several DNA lesions within the transcription elongation complex. However, little is known about the role of key elements of the RNAP active site in translesion transcription. Here, using recombinantly expressed proteins, in vitro transcription, kinetic analyses, and in vivo cell viability assays, we report that point amino acid substitutions in the trigger loop, a flexible element of the active site involved in nucleotide addition, can stimulate translesion RNA synthesis by Escherichia coli RNAP without altering the fidelity of nucleotide incorporation. We show that these substitutions also decrease transcriptional pausing and strongly affect the nucleotide addition cycle of RNAP by increasing the rate of nucleotide addition but also decreasing the rate of translocation. The secondary channel factors DksA and GreA modulated translesion transcription by RNAP, depending on changes in the trigger loop structure. We observed that although the mutant RNAPs stimulate translesion synthesis, their expression is toxic in vivo, especially under stress conditions. We conclude that the efficiency of translesion transcription can be significantly modulated by mutations affecting the conformational dynamics of the active site of RNAP, with potential effects on cellular stress responses and survival.
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Affiliation(s)
- Aleksei Agapov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Artem Ignatov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Matti Turtola
- Department of Biochemistry, University of Turku, Turku, Finland
| | | | - Daria Esyunina
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
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30
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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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31
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Boyaci H, Saecker RM, Campbell EA. Transcription initiation in mycobacteria: a biophysical perspective. Transcription 2019; 11:53-65. [PMID: 31880185 DOI: 10.1080/21541264.2019.1707612] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Recent biophysical studies of mycobacterial transcription have shed new light on this fundamental process in a group of bacteria that includes deadly pathogens such as Mycobacterium tuberculosis (Mtb), Mycobacterium abscessus (Mab), Mycobacterium leprae (Mlp), as well as the nonpathogenic Mycobacterium smegmatis (Msm). Most of the research has focused on Mtb, the causative agent of tuberculosis (TB), which remains one of the top ten causes of death globally. The enzyme RNA polymerase (RNAP) is responsible for all bacterial transcription and is a target for one of the crucial antibiotics used for TB treatment, rifampicin (Rif). Here, we summarize recent biophysical studies of mycobacterial RNAP that have advanced our understanding of the basic process of transcription, have revealed novel paradigms for regulation, and thus have provided critical information required for developing new antibiotics against this deadly disease.
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Affiliation(s)
- Hande Boyaci
- Laboratory of Molecular Biophysics, The Rockefeller University , New York, NY, USA
| | - Ruth M Saecker
- Laboratory of Molecular Biophysics, The Rockefeller University , New York, NY, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University , New York, NY, USA
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32
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Hawkins M, Dimude JU, Howard JAL, Smith AJ, Dillingham MS, Savery NJ, Rudolph CJ, McGlynn P. Direct removal of RNA polymerase barriers to replication by accessory replicative helicases. Nucleic Acids Res 2019; 47:5100-5113. [PMID: 30869136 PMCID: PMC6547429 DOI: 10.1093/nar/gkz170] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/22/2019] [Accepted: 03/08/2019] [Indexed: 11/24/2022] Open
Abstract
Bacterial genome duplication and transcription require simultaneous access to the same DNA template. Conflicts between the replisome and transcription machinery can lead to interruption of DNA replication and loss of genome stability. Pausing, stalling and backtracking of transcribing RNA polymerases add to this problem and present barriers to replisomes. Accessory helicases promote fork movement through nucleoprotein barriers and exist in viruses, bacteria and eukaryotes. Here, we show that stalled Escherichia coli transcription elongation complexes block reconstituted replisomes. This physiologically relevant block can be alleviated by the accessory helicase Rep or UvrD, resulting in the formation of full-length replication products. Accessory helicase action during replication-transcription collisions therefore promotes continued replication without leaving gaps in the DNA. In contrast, DinG does not promote replisome movement through stalled transcription complexes in vitro. However, our data demonstrate that DinG operates indirectly in vivo to reduce conflicts between replication and transcription. These results suggest that Rep and UvrD helicases operate on DNA at the replication fork whereas DinG helicase acts via a different mechanism.
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Affiliation(s)
- Michelle Hawkins
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Juachi U Dimude
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | | | - Abigail J Smith
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Mark S Dillingham
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Nigel J Savery
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Christian J Rudolph
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | - Peter McGlynn
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
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33
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Agapov A, Esyunina D, Kulbachinskiy A. Gre-family factors modulate DNA damage sensing by Deinococcus radiodurans RNA polymerase. RNA Biol 2019; 16:1711-1720. [PMID: 31416390 DOI: 10.1080/15476286.2019.1656027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Deinococcus radiodurans is a highly stress resistant bacterium that encodes universal as well as lineage-specific factors involved in DNA transcription and repair. However, the effects of DNA lesions on RNA synthesis by D. radiodurans RNA polymerase (RNAP) have never been studied. We investigated the ability of this RNAP to transcribe damaged DNA templates and demonstrated that various lesions significantly affect the efficiency and fidelity of RNA synthesis. DNA modifications that disrupt correct base-pairing can strongly inhibit transcription and increase nucleotide misincorporation by D. radiodurans RNAP. The universal transcription factor GreA and Deinococcus-specific factor Gfh1 stimulate RNAP stalling at various DNA lesions, depending on the type of the lesion and the presence of Mn2+ ions, abundant divalent cations in D. radiodurans. Furthermore, Gfh1 stimulates the action of the Mfd translocase, which removes transcription elongation complexes paused at the sites of DNA lesions. Thus, Gre-family factors in D. radiodurans might have evolved to increase the efficiency of DNA damage recognition by the transcription and repair machineries in this bacterium.
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Affiliation(s)
- Aleksei Agapov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Daria Esyunina
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
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34
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Ragheb M, Merrikh H. The enigmatic role of Mfd in replication-transcription conflicts in bacteria. DNA Repair (Amst) 2019; 81:102659. [PMID: 31311770 PMCID: PMC6892258 DOI: 10.1016/j.dnarep.2019.102659] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Conflicts between replication and transcription can have life-threatening consequences. RNA polymerase (RNAP) is the major impediment to replication progression, and its efficient removal from DNA should mitigate the consequences of collisions with replication. Cells have various proteins that can resolve conflicts by removing stalled (or actively translocating) RNAP from DNA. It would therefore seem logical that RNAP-associated factors, such as the bacterial DNA translocase Mfd, would minimize the effects of conflicts. Despite seemingly conclusive statements in most textbooks, the role of Mfd in conflicts remains an enigma. In this review, we will discuss the different physical states of RNAP during transcription, and how each distinct state can influence conflict severity and potentially trigger the involvement of Mfd. We propose models to explain the contradictory conclusions from published studies on the potential role of Mfd in resolving conflicts.
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Affiliation(s)
- Mark Ragheb
- Molecular and Cellular Biology Graduate Program and Medical Scientist Training Program, University of Washington, Seattle, WA, USA
| | - Houra Merrikh
- Department of Biochemistry, Vanderbilt University, Nashville, TN, 37205, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
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35
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Pattaro Júnior JR, Caruso ÍP, de Lima Neto QA, Duarte Junior FF, dos Santos Rando F, Gerhardt ECM, Fernandez MA, Seixas FAV. Biophysical characterization and molecular phylogeny of human KIN protein. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2019; 48:645-657. [DOI: 10.1007/s00249-019-01390-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/07/2019] [Accepted: 07/06/2019] [Indexed: 11/24/2022]
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36
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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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37
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Roberts JW. Mechanisms of Bacterial Transcription Termination. J Mol Biol 2019; 431:4030-4039. [PMID: 30978344 DOI: 10.1016/j.jmb.2019.04.003] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 03/28/2019] [Accepted: 04/02/2019] [Indexed: 01/28/2023]
Abstract
Bacterial transcription termination, described mostly for Escherichia coli, occurs in three recognized ways: intrinsic termination, an activity only of the core RNAP enzyme and transcript sequences that encode an RNA hairpin and terminal uridine-rich segment; termination by the enzyme Rho, an ATP-dependent RNA translocase that releases RNA by forcing uncharacterized structural changes in the elongating complex; and Mfd-dependent termination, the activity of an ATP-dependent DNA translocase that is thought to dissociate the elongation complex by exerting torque on a stalled RNAP. Intrinsic termination can be described in terms of the nucleic acid movements in the process, whereas the enzymatic mechanisms have been illuminated importantly by definitive structural and biochemical analysis of their activity.
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Affiliation(s)
- Jeffrey W Roberts
- Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA.
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38
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Fouqueau T, Blombach F, Cackett G, Carty AE, Matelska DM, Ofer S, Pilotto S, Phung DK, Werner F. The cutting edge of archaeal transcription. Emerg Top Life Sci 2018; 2:517-533. [PMID: 33525828 PMCID: PMC7289017 DOI: 10.1042/etls20180014] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 10/01/2018] [Accepted: 10/04/2018] [Indexed: 12/26/2022]
Abstract
The archaeal RNA polymerase (RNAP) is a double-psi β-barrel enzyme closely related to eukaryotic RNAPII in terms of subunit composition and architecture, promoter elements and basal transcription factors required for the initiation and elongation phase of transcription. Understanding archaeal transcription is, therefore, key to delineate the universally conserved fundamental mechanisms of transcription as well as the evolution of the archaeo-eukaryotic transcription machineries. The dynamic interplay between RNAP subunits, transcription factors and nucleic acids dictates the activity of RNAP and ultimately gene expression. This review focusses on recent progress in our understanding of (i) the structure, function and molecular mechanisms of known and less characterized factors including Elf1 (Elongation factor 1), NusA (N-utilization substance A), TFS4, RIP and Eta, and (ii) their evolution and phylogenetic distribution across the expanding tree of Archaea.
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Affiliation(s)
- Thomas Fouqueau
- RNAP laboratory, Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, U.K
| | - Fabian Blombach
- RNAP laboratory, Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, U.K
| | - Gwenny Cackett
- RNAP laboratory, Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, U.K
| | - Alice E Carty
- RNAP laboratory, Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, U.K
| | - Dorota M Matelska
- RNAP laboratory, Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, U.K
| | - Sapir Ofer
- RNAP laboratory, Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, U.K
| | - Simona Pilotto
- RNAP laboratory, Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, U.K
| | - Duy Khanh Phung
- RNAP laboratory, Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, U.K
| | - Finn Werner
- RNAP laboratory, Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, U.K
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39
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Ragheb MN, Thomason MK, Hsu C, Nugent P, Gage J, Samadpour AN, Kariisa A, Merrikh CN, Miller SI, Sherman DR, Merrikh H. Inhibiting the Evolution of Antibiotic Resistance. Mol Cell 2018; 73:157-165.e5. [PMID: 30449724 PMCID: PMC6320318 DOI: 10.1016/j.molcel.2018.10.015] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/17/2018] [Accepted: 10/09/2018] [Indexed: 11/30/2022]
Abstract
Efforts to battle antimicrobial resistance (AMR) are generally focused on developing novel antibiotics. However, history shows that resistance arises regardless of the nature or potency of new drugs. Here, we propose and provide evidence for an alternate strategy to resolve this problem: inhibiting evolution. We determined that the DNA translocase Mfd is an “evolvability factor” that promotes mutagenesis and is required for rapid resistance development to all antibiotics tested across highly divergent bacterial species. Importantly, hypermutator alleles that accelerate AMR development did not arise without Mfd, at least during evolution of trimethoprim resistance. We also show that Mfd’s role in AMR development depends on its interactions with the RNA polymerase subunit RpoB and the nucleotide excision repair protein UvrA. Our findings suggest that AMR development can be inhibited through inactivation of evolvability factors (potentially with “anti-evolution” drugs)—in particular, Mfd—providing an unexplored route toward battling the AMR crisis. The bacterial transcription-coupled repair (TCR) factor Mfd promotes mutagenesis Mfd-driven mutagenesis accelerates the evolution of antimicrobial resistance (AMR) The rapid evolution of AMR requires Mfd’s interaction with RpoB and UvrA Mfd may be an ideal target for “anti-evolution” drugs that inhibit AMR development
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Affiliation(s)
- Mark N Ragheb
- Department of Microbiology, University of Washington, Seattle, WA, USA; Molecular and Cellular Biology Graduate Program and Medical Scientist Training Program, University of Washington, Seattle, WA, USA
| | | | - Chris Hsu
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Patrick Nugent
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - John Gage
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | | | - Ankunda Kariisa
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | | | - Samuel I Miller
- Department of Microbiology, University of Washington, Seattle, WA, USA; Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - David R Sherman
- Center for Infectious Disease Research, Seattle, WA, USA; Interdiscipinary Program of Pathobiology, Department of Global Health, University of Washington, Seattle, WA, USA
| | - Houra Merrikh
- Department of Microbiology, University of Washington, Seattle, WA, USA; Department of Genome Sciences, University of Washington, Seattle, WA, USA.
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40
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Forcada-Nadal A, Llácer JL, Contreras A, Marco-Marín C, Rubio V. The P II-NAGK-PipX-NtcA Regulatory Axis of Cyanobacteria: A Tale of Changing Partners, Allosteric Effectors and Non-covalent Interactions. Front Mol Biosci 2018; 5:91. [PMID: 30483512 PMCID: PMC6243067 DOI: 10.3389/fmolb.2018.00091] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 10/18/2018] [Indexed: 11/13/2022] Open
Abstract
PII, a homotrimeric very ancient and highly widespread (bacteria, archaea, plants) key sensor-transducer protein, conveys signals of abundance or poorness of carbon, energy and usable nitrogen, converting these signals into changes in the activities of channels, enzymes, or of gene expression. PII sensing is mediated by the PII allosteric effectors ATP, ADP (and, in some organisms, AMP), 2-oxoglutarate (2OG; it reflects carbon abundance and nitrogen scarcity) and, in many plants, L-glutamine. Cyanobacteria have been crucial for clarification of the structural bases of PII function and regulation. They are the subject of this review because the information gathered on them provides an overall structure-based view of a PII regulatory network. Studies on these organisms yielded a first structure of a PII complex with an enzyme, (N-acetyl-Lglutamate kinase, NAGK), deciphering how PII can cause enzyme activation, and how it promotes nitrogen stockpiling as arginine in cyanobacteria and plants. They have also revealed the first clear-cut mechanism by which PII can control gene expression. A small adaptor protein, PipX, is sequestered by PII when nitrogen is abundant and is released when is scarce, swapping partner by binding to the 2OG-activated transcriptional regulator NtcA, co-activating it. The structures of PII-NAGK, PII-PipX, PipX alone, of NtcA in inactive and 2OG-activated forms and as NtcA-2OG-PipX complex, explain structurally PII regulatory functions and reveal the changing shapes and interactions of the T-loops of PII depending on the partner and on the allosteric effectors bound to PII. Cyanobacterial studies have also revealed that in the PII-PipX complex PipX binds an additional transcriptional factor, PlmA, thus possibly expanding PipX roles beyond NtcA-dependency. Further exploration of these roles has revealed a functional interaction of PipX with PipY, a pyridoxal-phosphate (PLP) protein involved in PLP homeostasis whose mutations in the human ortholog cause epilepsy. Knowledge of cellular levels of the different components of this PII-PipX regulatory network and of KD values for some of the complexes provides the basic background for gross modeling of the system at high and low nitrogen abundance. The cyanobacterial network can guide searches for analogous components in other organisms, particularly of PipX functional analogs.
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Affiliation(s)
- Alicia Forcada-Nadal
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - José Luis Llácer
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras - Instituto de Salud Carlos III, Valencia, Spain
| | - Asunción Contreras
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Clara Marco-Marín
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras - Instituto de Salud Carlos III, Valencia, Spain
| | - Vicente Rubio
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras - Instituto de Salud Carlos III, Valencia, Spain
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An Orphan MbtH-Like Protein Interacts with Multiple Nonribosomal Peptide Synthetases in Myxococcus xanthus DK1622. J Bacteriol 2018; 200:JB.00346-18. [PMID: 30126939 DOI: 10.1128/jb.00346-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/13/2018] [Indexed: 11/20/2022] Open
Abstract
One mechanism by which bacteria and fungi produce bioactive natural products is the use of nonribosomal peptide synthetases (NRPSs). Many NRPSs in bacteria require members of the MbtH-like protein (MLP) superfamily for their solubility or function. Although MLPs are known to interact with the adenylation domains of NRPSs, the role MLPs play in NRPS enzymology has yet to be elucidated. MLPs are nearly always encoded within the biosynthetic gene clusters (BGCs) that also code for the NRPSs that interact with the MLP. Here, we identify 50 orphan MLPs from diverse bacteria. An orphan MLP is one that is encoded by a gene that is not directly adjacent to genes predicted to be involved in nonribosomal peptide biosynthesis. We targeted the orphan MLP MXAN_3118 from Myxococcus xanthus DK1622 for characterization. The M. xanthus DK1622 genome contains 15 NRPS-encoding BGCs but only one MLP-encoding gene (MXAN_3118). We tested the hypothesis that MXAN_3118 interacts with one or more NRPS using a combination of in vivo and in vitro assays. We determined that MXAN_3118 interacts with at least seven NRPSs from distinct BGCs. We show that one of these BGCs codes for NRPS enzymology that likely produces a valine-rich natural product that inhibits the clumping of M. xanthus DK1622 in liquid culture. MXAN_3118 is the first MLP to be identified that naturally interacts with multiple NRPS systems in a single organism. The finding of an MLP that naturally interacts with multiple NRPS systems suggests it may be harnessed as a "universal" MLP for generating functional hybrid NRPSs.IMPORTANCE MbtH-like proteins (MLPs) are essential accessory proteins for the function of many nonribosomal peptide synthetases (NRPSs). We identified 50 MLPs from diverse bacteria that are coded by genes that are not located near any NRPS-encoding biosynthetic gene clusters (BGCs). We define these as orphan MLPs because their NRPS partner(s) is unknown. Investigations into the orphan MLP from Myxococcus xanthus DK1622 determined that it interacts with NRPSs from at least seven distinct BGCs. Support for these MLP-NRPS interactions came from the use of a bacterial two-hybrid assay and copurification of the MLP with various NRPSs. The flexibility of this MLP to naturally interact with multiple NRPSs led us to hypothesize that this MLP may be used as a "universal" MLP during the construction of functional hybrid NRPSs.
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Warren GM, Stein RA, Mchaourab HS, Eichman BF. Movement of the RecG Motor Domain upon DNA Binding Is Required for Efficient Fork Reversal. Int J Mol Sci 2018; 19:ijms19103049. [PMID: 30301235 PMCID: PMC6213257 DOI: 10.3390/ijms19103049] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 09/29/2018] [Accepted: 10/04/2018] [Indexed: 01/20/2023] Open
Abstract
RecG catalyzes reversal of stalled replication forks in response to replication stress in bacteria. The protein contains a fork recognition (“wedge”) domain that binds branched DNA and a superfamily II (SF2) ATPase motor that drives translocation on double-stranded (ds)DNA. The mechanism by which the wedge and motor domains collaborate to catalyze fork reversal in RecG and analogous eukaryotic fork remodelers is unknown. Here, we used electron paramagnetic resonance (EPR) spectroscopy to probe conformational changes between the wedge and ATPase domains in response to fork DNA binding by Thermotoga maritima RecG. Upon binding DNA, the ATPase-C lobe moves away from both the wedge and ATPase-N domains. This conformational change is consistent with a model of RecG fully engaged with a DNA fork substrate constructed from a crystal structure of RecG bound to a DNA junction together with recent cryo-electron microscopy (EM) structures of chromatin remodelers in complex with dsDNA. We show by mutational analysis that a conserved loop within the translocation in RecG (TRG) motif that was unstructured in the RecG crystal structure is essential for fork reversal and DNA-dependent conformational changes. Together, this work helps provide a more coherent model of fork binding and remodeling by RecG and related eukaryotic enzymes.
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Affiliation(s)
- Garrett M Warren
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA.
| | - Richard A Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA.
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA.
| | - Brandt F Eichman
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA.
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43
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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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44
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Peter S, Bezdan D, Oberhettinger P, Vogel W, Dörfel D, Dick J, Marschal M, Liese J, Weidenmaier C, Autenrieth I, Ossowski S, Willmann M. Whole-genome sequencing enabling the detection of a colistin-resistant hypermutating Citrobacter werkmanii strain harbouring a novel metallo-β-lactamase VIM-48. Int J Antimicrob Agents 2018; 51:867-874. [DOI: 10.1016/j.ijantimicag.2018.01.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 01/19/2018] [Accepted: 01/20/2018] [Indexed: 11/27/2022]
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45
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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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46
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Berry KE, Hochschild A. A bacterial three-hybrid assay detects Escherichia coli Hfq-sRNA interactions in vivo. Nucleic Acids Res 2018; 46:e12. [PMID: 29140461 PMCID: PMC5778611 DOI: 10.1093/nar/gkx1086] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/21/2017] [Accepted: 10/20/2017] [Indexed: 01/08/2023] Open
Abstract
The interaction of RNA molecules with proteins is a critical aspect of gene regulation across all domains of life. Here, we report the development of a bacterial three-hybrid (B3H) assay to genetically detect RNA-protein interactions. The basis for this three-hybrid assay is a transcription-based bacterial two-hybrid assay that has been used widely to detect and dissect protein-protein interactions. In the three-hybrid assay, a DNA-bound protein with a fused RNA-binding moiety (the coat protein of bacteriophage MS2 (MS2CP)) is used to recruit a hybrid RNA upstream of a test promoter. The hybrid RNA consists of a constant region that binds the tethered MS2CP and a variable region. Interaction between the variable region of the hybrid RNA and a target RNA-binding protein that is fused to a subunit of Escherichia coli RNA polymerase (RNAP) stabilizes the binding of RNAP to the test promoter, thereby activating transcription of a reporter gene. We demonstrate that this three-hybrid assay detects interaction between non-coding small RNAs (sRNAs) and the hexameric RNA chaperone Hfq from E. coli and enables the identification of Hfq mutants with sRNA-binding defects. Our findings suggest that this B3H assay will be broadly applicable for the study of RNA-protein interactions.
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Affiliation(s)
- Katherine E Berry
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Ann Hochschild
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
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47
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Le TT, Yang Y, Tan C, Suhanovsky MM, Fulbright RM, Inman JT, Li M, Lee J, Perelman S, Roberts JW, Deaconescu AM, Wang MD. Mfd Dynamically Regulates Transcription via a Release and Catch-Up Mechanism. Cell 2017; 172:344-357.e15. [PMID: 29224782 DOI: 10.1016/j.cell.2017.11.017] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 09/21/2017] [Accepted: 11/09/2017] [Indexed: 11/25/2022]
Abstract
The bacterial Mfd ATPase is increasingly recognized as a general transcription factor that participates in the resolution of transcription conflicts with other processes/roadblocks. This function stems from Mfd's ability to preferentially act on stalled RNA polymerases (RNAPs). However, the mechanism underlying this preference and the subsequent coordination between Mfd and RNAP have remained elusive. Here, using a novel real-time translocase assay, we unexpectedly discovered that Mfd translocates autonomously on DNA. The speed and processivity of Mfd dictate a "release and catch-up" mechanism to efficiently patrol DNA for frequently stalled RNAPs. Furthermore, we showed that Mfd prevents RNAP backtracking or rescues a severely backtracked RNAP, allowing RNAP to overcome stronger obstacles. However, if an obstacle's resistance is excessive, Mfd dissociates the RNAP, clearing the DNA for other processes. These findings demonstrate a remarkably delicate coordination between Mfd and RNAP, allowing efficient targeting and recycling of Mfd and expedient conflict resolution.
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Affiliation(s)
- Tung T Le
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Yi Yang
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Chuang Tan
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Margaret M Suhanovsky
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02903, USA
| | | | - James T Inman
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Ming Li
- Department of Chemistry, Cornell University, Ithaca, NY 14853, USA
| | - Jaeyoon Lee
- Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Sarah Perelman
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02903, USA
| | - Jeffrey W Roberts
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Alexandra M Deaconescu
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02903, USA
| | - Michelle D Wang
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA.
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48
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Structural basis for the initiation of eukaryotic transcription-coupled DNA repair. Nature 2017; 551:653-657. [PMID: 29168508 PMCID: PMC5907806 DOI: 10.1038/nature24658] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 10/18/2017] [Indexed: 12/19/2022]
Abstract
Eukaryotic transcription-coupled repair (TCR), or transcription-coupled nucleotide excision repair (TC-NER), is an important and well-conserved sub-pathway of nucleotide excision repair (NER) that preferentially removes DNA lesions from the template strand blocking RNA polymerase II (Pol II) translocation1,2. Cockayne syndrome group B protein in humans (CSB, or ERCC6), or its yeast orthologs (Rad26 in Saccharomyces cerevisiae and Rhp26 in Schizosaccharomyces pombe), is among the first proteins to be recruited to the lesion-arrested Pol II during initiation of eukaryotic TCR1,3–10. Mutations in CSB are associated with Cockayne syndrome, an autosomal-recessive neurologic disorder characterized by progeriod features, growth failure, and photosensitivity1. The molecular mechanism of eukaryotic TCR initiation remains elusive, with several long-standing questions unanswered: How do cells distinguish DNA lesion-arrested Pol II from other forms of arrested Pol II? How does CSB interact with the arrested Pol II complex? What is the role of CSB in TCR initiation? The lack of structures of CSB or the Pol II-CSB complex have hindered our ability to answer those questions. Here we report the first structure of S. cerevisiae Pol II-Rad26 complex solved by cryo-electron microscopy (cryo-EM). The structure reveals that Rad26 binds to the DNA upstream of Pol II where it dramatically alters its path. Our structural and functional data suggest that the conserved Swi2/Snf2-family core ATPase domain promotes forward movement of Pol II and elucidate key roles for Rad26/CSB in both TCR and transcription elongation.
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Uncoupling of Protease trans-Cleavage and Helicase Activities in Pestivirus NS3. J Virol 2017; 91:JVI.01094-17. [PMID: 28835495 DOI: 10.1128/jvi.01094-17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/07/2017] [Indexed: 01/25/2023] Open
Abstract
The nonstructural protein NS3 from the Flaviviridae family is a multifunctional protein that contains an N-terminal protease and a C-terminal helicase, playing essential roles in viral polyprotein processing and genome replication. Here we report a full-length crystal structure of the classical swine fever virus (CSFV) NS3 in complex with its NS4A protease cofactor segment (PCS) at a 2.35-Å resolution. The structure reveals a previously unidentified ∼2,200-Å2 intramolecular protease-helicase interface comprising three clusters of interactions, representing a "closed" global conformation related to the NS3-NS4A cis-cleavage event. Although this conformation is incompatible with protease trans-cleavage, it appears to be functionally important and beneficial to the helicase activity, as the mutations designed to perturb this conformation impaired both the helicase activities in vitro and virus production in vivo Our work reveals important features of protease-helicase coordination in pestivirus NS3 and provides a key basis for how different conformational states may explicitly contribute to certain functions of this natural protease-helicase fusion protein.IMPORTANCE Many RNA viruses encode helicases to aid their RNA genome replication and transcription by unwinding structured RNA. Being naturally fused to a protease participating in viral polyprotein processing, the NS3 helicases encoded by the Flaviviridae family viruses are unique. Therefore, how these two enzyme modules coordinate in a single polypeptide is of particular interest. Here we report a previously unidentified conformation of pestivirus NS3 in complex with its NS4A protease cofactor segment (PCS). This conformational state is related to the protease cis-cleavage event and is optimal for the function of helicase. This work provides an important basis to understand how different enzymatic activities of NS3 may be achieved by the coordination between the protease and helicase through different conformational states.
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50
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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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