1
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Bonde NJ, Wood EA, Myers KS, Place M, Keck JL, Cox MM. Identification of recG genetic interactions in Escherichia coli by transposon sequencing. J Bacteriol 2023; 205:e0018423. [PMID: 38019006 PMCID: PMC10870727 DOI: 10.1128/jb.00184-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 08/07/2023] [Indexed: 11/30/2023] Open
Abstract
IMPORTANCE DNA damage and subsequent DNA repair processes are mutagenic in nature and an important driver of evolution in prokaryotes, including antibiotic resistance development. Genetic screening approaches, such as transposon sequencing (Tn-seq), have provided important new insights into gene function and genetic relationships. Here, we employed Tn-seq to gain insight into the function of the recG gene, which renders Escherichia coli cells moderately sensitive to a variety of DNA-damaging agents when they are absent. The reported recG genetic interactions can be used in combination with future screens to aid in a more complete reconstruction of DNA repair pathways in bacteria.
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Affiliation(s)
- Nina J. Bonde
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Elizabeth A. Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kevin S. Myers
- Great Lakes Bioenergy Research Center and the Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Michael Place
- Great Lakes Bioenergy Research Center and the Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - James L. Keck
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Michael M. Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
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2
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Cox MM, Goodman MF, Keck JL, van Oijen A, Lovett ST, Robinson A. Generation and Repair of Postreplication Gaps in Escherichia coli. Microbiol Mol Biol Rev 2023; 87:e0007822. [PMID: 37212693 PMCID: PMC10304936 DOI: 10.1128/mmbr.00078-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023] Open
Abstract
When replication forks encounter template lesions, one result is lesion skipping, where the stalled DNA polymerase transiently stalls, disengages, and then reinitiates downstream to leave the lesion behind in a postreplication gap. Despite considerable attention in the 6 decades since postreplication gaps were discovered, the mechanisms by which postreplication gaps are generated and repaired remain highly enigmatic. This review focuses on postreplication gap generation and repair in the bacterium Escherichia coli. New information to address the frequency and mechanism of gap generation and new mechanisms for their resolution are described. There are a few instances where the formation of postreplication gaps appears to be programmed into particular genomic locations, where they are triggered by novel genomic elements.
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Affiliation(s)
- Michael M. Cox
- Department of Biochemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Myron F. Goodman
- Department of Biological Sciences, University of Southern California, University Park, Los Angeles, California, USA
- Department of Chemistry, University of Southern California, University Park, Los Angeles, California, USA
| | - James L. Keck
- Department of Biological Chemistry, University of Wisconsin—Madison School of Medicine, Madison, Wisconsin, USA
| | - Antoine van Oijen
- Molecular Horizons, University of Wollongong, Wollongong, New South Wales, Australia
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, Australia
| | - Susan T. Lovett
- Department of Biology, Brandeis University, Waltham, Massachusetts, USA
| | - Andrew Robinson
- Molecular Horizons, University of Wollongong, Wollongong, New South Wales, Australia
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, Australia
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3
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Pham P, Wood EA, Cox MM, Goodman MF. RecA and SSB genome-wide distribution in ssDNA gaps and ends in Escherichia coli. Nucleic Acids Res 2023; 51:5527-5546. [PMID: 37070184 PMCID: PMC10287960 DOI: 10.1093/nar/gkad263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 04/19/2023] Open
Abstract
Single-stranded DNA (ssDNA) gapped regions are common intermediates in DNA transactions. Using a new non-denaturing bisulfite treatment combined with ChIP-seq, abbreviated 'ssGap-seq', we explore RecA and SSB binding to ssDNA on a genomic scale in E. coli in a wide range of genetic backgrounds. Some results are expected. During log phase growth, RecA and SSB assembly profiles coincide globally, concentrated on the lagging strand and enhanced after UV irradiation. Unexpected results also abound. Near the terminus, RecA binding is favored over SSB, binding patterns change in the absence of RecG, and the absence of XerD results in massive RecA assembly. RecA may substitute for the absence of XerCD to resolve chromosome dimers. A RecA loading pathway may exist that is independent of RecBCD and RecFOR. Two prominent and focused peaks of RecA binding revealed a pair of 222 bp and GC-rich repeats, equidistant from dif and flanking the Ter domain. The repeats, here named RRS for replication risk sequence, trigger a genomically programmed generation of post-replication gaps that may play a special role in relieving topological stress during replication termination and chromosome segregation. As demonstrated here, ssGap-seq provides a new window on previously inaccessible aspects of ssDNA metabolism.
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Affiliation(s)
- Phuong Pham
- Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA 90089-2910, USA
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA
| | - Myron F Goodman
- Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA 90089-2910, USA
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4
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Osorio Garcia MA, Wood EA, Keck JL, Cox MM. Interaction with single-stranded DNA-binding protein (SSB) modulates Escherichia coli RadD DNA repair activities. J Biol Chem 2023; 299:104773. [PMID: 37142225 DOI: 10.1016/j.jbc.2023.104773] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/06/2023] Open
Abstract
The bacterial RadD enzyme is important for multiple genome maintenance pathways, including RecA DNA strand exchange and RecA-independent suppression of DNA crossover template switching. However, much remains unknown about the precise roles of RadD. One potential clue into RadD mechanisms is its direct interaction with the single-stranded DNA binding protein (SSB), which coats single-stranded DNA exposed during genome maintenance reactions in cells. Interaction with SSB stimulates the ATPase activity of RadD. To probe the mechanism and importance of RadD:SSB complex formation, we identified a pocket on RadD that is essential for binding SSB. In a mechanism shared with many other SSB-interacting proteins, RadD uses a hydrophobic pocket framed by basic residues to bind the C-terminal end of SSB. We found that RadD variants that substitute acidic residues for basic residues in the SSB binding site impair RadD:SSB complex formation and eliminate SSB stimulation of RadD ATPase activity in vitro. Additionally, mutant E. coli strains carrying charge reversal radD changes display increased sensitivity to DNA damaging agents synergistically with deletions of radA and recG, although the phenotypes of the SSB-binding radD mutants are not as severe as a full radD deletion. This suggests that cellular RadD requires an intact the interaction with SSB for full RadD function.
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Affiliation(s)
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin, Madison, Madison, WI 53706
| | - James L Keck
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA.
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin, Madison, Madison, WI 53706.
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5
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Shinn MK, Chaturvedi SK, Kozlov AG, Lohman T. Allosteric effects of E. coli SSB and RecR proteins on RecO protein binding to DNA. Nucleic Acids Res 2023; 51:2284-2297. [PMID: 36808259 PMCID: PMC10018359 DOI: 10.1093/nar/gkad084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 02/22/2023] Open
Abstract
Escherichia coli single stranded (ss) DNA binding protein (SSB) plays essential roles in DNA maintenance. It binds ssDNA with high affinity through its N-terminal DNA binding core and recruits at least 17 different SSB interacting proteins (SIPs) that are involved in DNA replication, recombination, and repair via its nine amino acid acidic tip (SSB-Ct). E. coli RecO, a SIP, is an essential recombination mediator protein in the RecF pathway of DNA repair that binds ssDNA and forms a complex with E. coli RecR protein. Here, we report ssDNA binding studies of RecO and the effects of a 15 amino acid peptide containing the SSB-Ct monitored by light scattering, confocal microscope imaging, and analytical ultracentrifugation (AUC). We find that one RecO monomer can bind the oligodeoxythymidylate, (dT)15, while two RecO monomers can bind (dT)35 in the presence of the SSB-Ct peptide. When RecO is in molar excess over ssDNA, large RecO-ssDNA aggregates occur that form with higher propensity on ssDNA of increasing length. Binding of RecO to the SSB-Ct peptide inhibits RecO-ssDNA aggregation. RecOR complexes can bind ssDNA via RecO, but aggregation is suppressed even in the absence of the SSB-Ct peptide, demonstrating an allosteric effect of RecR on RecO binding to ssDNA. Under conditions where RecO binds ssDNA but does not form aggregates, SSB-Ct binding enhances the affinity of RecO for ssDNA. For RecOR complexes bound to ssDNA, we also observe a shift in RecOR complex equilibrium towards a RecR4O complex upon binding SSB-Ct. These results suggest a mechanism by which SSB recruits RecOR to facilitate loading of RecA onto ssDNA gaps.
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Affiliation(s)
- Min Kyung Shinn
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
- Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Sumit K Chaturvedi
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Biophysics, University of Delhi South Campus, New Delhi 110021, India
| | - Alexander G Kozlov
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Timothy M Lohman
- To whom correspondence should be addressed. Tel: +1 314 362 4393; Fax: +1 314 362 7183;
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6
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Calvo PA, Mateo-Cáceres V, Díaz-Arco S, Redrejo-Rodríguez M, de Vega M. The enterohemorrhagic Escherichia coli insertion sequence-excision enhancer protein is a DNA polymerase with microhomology-mediated end-joining activity. Nucleic Acids Res 2023; 51:1189-1207. [PMID: 36715333 PMCID: PMC9943667 DOI: 10.1093/nar/gkad017] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/30/2022] [Accepted: 01/05/2023] [Indexed: 01/31/2023] Open
Abstract
Bacterial genomes contain an abundance of transposable insertion sequence (IS) elements that are essential for genome evolution and fitness. Among them, IS629 is present in most strains of enterohemorrhagic Escherichia coli O157 and accounts for many polymorphisms associated with gene inactivation and/or genomic deletions. The excision of IS629 from the genome is promoted by IS-excision enhancer (IEE) protein. Despite IEE has been identified in the most pathogenic serotypes of E. coli, its biochemical features that could explain its role in IS excision are not yet understood. We show that IEE is present in >30% of all available E. coli genome assemblies, and is highly conserved and very abundant within enterohemorrhagic, enteropathogenic and enterotoxigenic genomes. In vitro analysis of the recombinant protein from E. coli O157:H7 revealed the presence of a Mn2+-dependent error-prone DNA polymerase activity in its N-terminal archaeo-eukaryotic primase (AEP) domain able to promote dislocations of the primer and template strands. Importantly, IEE could efficiently perform in vitro an end-joining reaction of 3'-single-strand DNA overhangs with ≥4 bp of homology requiring both the N-terminal AEP and C-terminal helicase domains. The proposed role for IEE in the novel IS excision mechanism is discussed.
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Affiliation(s)
- Patricia A Calvo
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Nicolás Cabrera 1, Madrid 28049, Spain
| | - Víctor Mateo-Cáceres
- Department of Biochemistry, School of Medicine, Universidad Autónoma de Madrid and Instituto de Investigaciones Biomédicas Alberto Sols (Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas), Madrid, Spain
| | - Silvia Díaz-Arco
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Nicolás Cabrera 1, Madrid 28049, Spain
| | - Modesto Redrejo-Rodríguez
- Department of Biochemistry, School of Medicine, Universidad Autónoma de Madrid and Instituto de Investigaciones Biomédicas Alberto Sols (Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas), Madrid, Spain
| | - Miguel de Vega
- To whom correspondence should be addressed. Tel: +34 911964717; Fax: +34 911964420;
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7
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Biochemical and Structural Analyses Shed Light on the Mechanisms of RadD DNA Binding and Its ATPase from Escherichia coli. Int J Mol Sci 2023; 24:ijms24010741. [PMID: 36614183 PMCID: PMC9821108 DOI: 10.3390/ijms24010741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023] Open
Abstract
DNA double-strand breaks (DSBs) are the most perilous and harmful type of DNA damage and can cause tumorigenesis or cell death if left repaired with an error or unrepaired. RadD, a member of the SF2 family, is a recently discovered DNA repair protein involved in the repair of DSBs after radiation or chemical damage. However, the function of RadD in DNA repair remains unclear. Here, we determined the crystal structures of RadD/ATPγS and RadD/ATP complexes and revealed the novel mechanism of RadD binding to DNA and ATP hydrolysis with biochemical data. In the RadD catalytic center, the Gly34 and Gly36 on the P-loop are key residues for ATP binding besides the conserved amino acids Lys37 and Arg343 in the SF2 family. If any of them mutate, then RadD loses ATPase activity. Asp117 polarizes the attacking water molecule, which then starts a nucleophilic reaction toward γ-phosphate, forming the transition state. Lys68 acts as a pocket switch to regulate substrate entry and product release. We revealed that the C-terminal peptide of single-stranded DNA-binding protein (SSB) binds the RadD C-terminal domain (CTD) and promotes the RadD ATPase activity. Our mutagenesis studies confirmed that the residues Arg428 on the zinc finger domain (ZFD) and Lys488 on the CTD of RadD are the key sites for binding branched DNA. Using the Coot software combined with molecular docking, we propose a RadD-binding DNA model for the DNA damage repair process.
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8
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Revitt‐Mills SA, Wright EK, Vereker M, O'Flaherty C, McPherson F, Dawson C, van Oijen AM, Robinson A. Defects in DNA double‐strand break repair resensitize antibiotic‐resistant
Escherichia coli
to multiple bactericidal antibiotics. Microbiologyopen 2022; 11:e1316. [PMCID: PMC9500592 DOI: 10.1002/mbo3.1316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 09/03/2022] [Accepted: 09/03/2022] [Indexed: 11/11/2022] Open
Affiliation(s)
- Sarah A. Revitt‐Mills
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Elizabeth K. Wright
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Madaline Vereker
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Callum O'Flaherty
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Fairley McPherson
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Catherine Dawson
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Antoine M. van Oijen
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
| | - Andrew Robinson
- School of Chemistry and Molecular Bioscience, Molecular Horizons Institute University of Wollongong Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute Wollongong New South Wales Australia
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9
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mobileOG-db: a Manually Curated Database of Protein Families Mediating the Life Cycle of Bacterial Mobile Genetic Elements. Appl Environ Microbiol 2022; 88:e0099122. [PMID: 36036594 PMCID: PMC9499024 DOI: 10.1128/aem.00991-22] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial mobile genetic elements (MGEs) encode functional modules that perform both core and accessory functions for the element, the latter of which are often only transiently associated with the element. The presence of these accessory genes, which are often close homologs to primarily immobile genes, incur high rates of false positives and, therefore, limits the usability of these databases for MGE annotation. To overcome this limitation, we analyzed 10,776,849 protein sequences derived from eight MGE databases to compile a comprehensive set of 6,140 manually curated protein families that are linked to the “life cycle” (integration/excision, replication/recombination/repair, transfer, stability/transfer/defense, and phage-specific processes) of plasmids, phages, integrative, transposable, and conjugative elements. We overlay experimental information where available to create a tiered annotation scheme of high-quality annotations and annotations inferred exclusively through bioinformatic evidence. We additionally provide an MGE-class label for each entry (e.g., plasmid or integrative element), and assign to each entry a major and minor category. The resulting database, mobileOG-db (for mobile orthologous groups), comprises over 700,000 deduplicated sequences encompassing five major mobileOG categories and more than 50 minor categories, providing a structured language and interpretable basis for an array of MGE-centered analyses. mobileOG-db can be accessed at mobileogdb.flsi.cloud.vt.edu/, where users can select, refine, and analyze custom subsets of the dynamic mobilome. IMPORTANCE The analysis of bacterial mobile genetic elements (MGEs) in genomic data is a critical step toward profiling the root causes of antibiotic resistance, phenotypic or metabolic diversity, and the evolution of bacterial genera. Existing methods for MGE annotation pose high barriers of biological and computational expertise to properly harness. To bridge this gap, we systematically analyzed 10,776,849 proteins derived from eight databases of MGEs to identify 6,140 MGE protein families that can serve as candidate hallmarks, i.e., proteins that can be used as “signatures” of MGEs to aid annotation. The resulting resource, mobileOG-db, provides a multilevel classification scheme that encompasses plasmid, phage, integrative, and transposable element protein families categorized into five major mobileOG categories and more than 50 minor categories. mobileOG-db thus provides a rich resource for simple and intuitive element annotation that can be integrated seamlessly into existing MGE detection pipelines and colocalization analyses.
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10
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Charles C, Conde C, Biet F, Boschiroli ML, Michelet L. IS6110 Copy Number in Multi-Host Mycobacterium bovis Strains Circulating in Bovine Tuberculosis Endemic French Regions. Front Microbiol 2022; 13:891902. [PMID: 35814675 PMCID: PMC9260277 DOI: 10.3389/fmicb.2022.891902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 05/03/2022] [Indexed: 11/13/2022] Open
Abstract
IS6110 is an insertion sequence found in the Mycobacterium tuberculosis complex, to which Mycobacterium bovis belongs, which can play a role in genome plasticity and in bacterial evolution. In this study, the abundance and location of IS6110 on M. bovis genomic data of French animal field strains were studied. A first analysis was performed on a panel of 81 strains that reflect the national M. bovis population’s genetic diversity. The results show that more than one-third of them are IS6110 multicopy and that 10% have IS6110 in a high copy number (more than 6 copies). Multicopy strains are those circulating in the regions where prevalence was above the national average. Further study of 93 such strains, with an IS6110 copy number of 10-12, showed stability of IS6110 copy number and genome location over time and between host species. The correlation between M. bovis multicopy strains and high bovine tuberculosis (bTB) prevalence leads us to consider whether their epidemiological success could be partly due to genetic changes originated by IS6110 transposition.
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Affiliation(s)
- Ciriac Charles
- ANSES, Animal Health Laboratory, National Reference Laboratory for Tuberculosis, Paris-Est University, Paris, France
- INRAE, ISP, Université de Tours, Nouzilly, France
| | - Cyril Conde
- INRAE, ISP, Université de Tours, Nouzilly, France
| | - Franck Biet
- INRAE, ISP, Université de Tours, Nouzilly, France
| | - Maria Laura Boschiroli
- ANSES, Animal Health Laboratory, National Reference Laboratory for Tuberculosis, Paris-Est University, Paris, France
| | - Lorraine Michelet
- ANSES, Animal Health Laboratory, National Reference Laboratory for Tuberculosis, Paris-Est University, Paris, France
- *Correspondence: Lorraine Michelet,
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11
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Osorio Garcia MA, Satyshur KA, Cox MM, Keck JL. X-ray crystal structure of the Escherichia coli RadD DNA repair protein bound to ADP reveals a novel zinc ribbon domain. PLoS One 2022; 17:e0266031. [PMID: 35482735 PMCID: PMC9049331 DOI: 10.1371/journal.pone.0266031] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/11/2022] [Indexed: 11/19/2022] Open
Abstract
Genome maintenance is an essential process in all cells. In prokaryotes, the RadD protein is important for survival under conditions that include DNA-damaging radiation. Precisely how RadD participates in genome maintenance remains unclear. Here we present a high-resolution X-ray crystal structure of ADP-bound Escherichia coli RadD, revealing a zinc-ribbon element that was not modelled in a previous RadD crystal structure. Insights into the mode of nucleotide binding and additional structure refinement afforded by the new RadD model will help to drive investigations into the activity of RadD as a genome stability and repair factor.
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Affiliation(s)
- Miguel A. Osorio Garcia
- Department of Biochemistry, University of Wisconsin, Madison, Madison, WI, United States of America
- * E-mail: (MMC); (JLK); (MAOG)
| | - Kenneth A. Satyshur
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States of America
| | - Michael M. Cox
- Department of Biochemistry, University of Wisconsin, Madison, Madison, WI, United States of America
- * E-mail: (MMC); (JLK); (MAOG)
| | - James L. Keck
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States of America
- * E-mail: (MMC); (JLK); (MAOG)
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12
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Bonde NJ, Romero ZJ, Chitteni-Pattu S, Cox MM. RadD is a RecA-dependent accessory protein that accelerates DNA strand exchange. Nucleic Acids Res 2022; 50:2201-2210. [PMID: 35150260 PMCID: PMC8887467 DOI: 10.1093/nar/gkac041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/11/2022] [Accepted: 02/10/2022] [Indexed: 02/01/2023] Open
Abstract
In rapidly growing cells, with recombinational DNA repair required often and a new replication fork passing every 20 min, the pace of RecA-mediated DNA strand exchange is potentially much too slow for bacterial DNA metabolism. The enigmatic RadD protein, a putative SF2 family helicase, exhibits no independent helicase activity on branched DNAs. Instead, RadD greatly accelerates RecA-mediated DNA strand exchange, functioning only when RecA protein is present. The RadD reaction requires the RadD ATPase activity, does not require an interaction with SSB, and may disassemble RecA filaments as it functions. We present RadD as a new class of enzyme, an accessory protein that accelerates DNA strand exchange, possibly with a helicase-like action, in a reaction that is entirely RecA-dependent. RadD is thus a DNA strand exchange (recombination) synergist whose primary function is to coordinate closely with and accelerate the DNA strand exchange reactions promoted by the RecA recombinase. Multiple observations indicate a uniquely close coordination of RadD with RecA function.
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Affiliation(s)
- Nina J Bonde
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Zachary J Romero
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
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13
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Behrmann MS, Perera HM, Hoang JM, Venkat TA, Visser BJ, Bates D, Trakselis MA. Targeted chromosomal Escherichia coli:dnaB exterior surface residues regulate DNA helicase behavior to maintain genomic stability and organismal fitness. PLoS Genet 2021; 17:e1009886. [PMID: 34767550 PMCID: PMC8612530 DOI: 10.1371/journal.pgen.1009886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 11/24/2021] [Accepted: 10/18/2021] [Indexed: 12/05/2022] Open
Abstract
Helicase regulation involves modulation of unwinding speed to maintain coordination of DNA replication fork activities and is vital for replisome progression. Currently, mechanisms for helicase regulation that involve interactions with both DNA strands through a steric exclusion and wrapping (SEW) model and conformational shifts between dilated and constricted states have been examined in vitro. To better understand the mechanism and cellular impact of helicase regulation, we used CRISPR-Cas9 genome editing to study four previously identified SEW-deficient mutants of the bacterial replicative helicase DnaB. We discovered that these four SEW mutations stabilize constricted states, with more fully constricted mutants having a generally greater impact on genomic stress, suggesting a dynamic model for helicase regulation that involves both excluded strand interactions and conformational states. These dnaB mutations result in increased chromosome complexities, less stable genomes, and ultimately less viable and fit strains. Specifically, dnaB:mut strains present with increased mutational frequencies without significantly inducing SOS, consistent with leaving single-strand gaps in the genome during replication that are subsequently filled with lower fidelity. This work explores the genomic impacts of helicase dysregulation in vivo, supporting a combined dynamic regulatory mechanism involving a spectrum of DnaB conformational changes and relates current mechanistic understanding to functional helicase behavior at the replication fork. DNA replication is a vital biological process, and the proteins involved are structurally and functionally conserved across all domains of life. As our fundamental knowledge of genes and genetics grows, so does our awareness of links between acquired genetic mutations and disease. Understanding how genetic material is replicated accurately and efficiently and with high fidelity is the foundation to identifying and solving genome-based diseases. E. coli are model organisms, containing core replisome proteins, but lack the complexity of the human replication system, making them ideal for investigating conserved replisome behaviors. The helicase enzyme acts at the forefront of the replication fork to unwind the DNA helix and has also been shown to help coordinate other replisome functions. In this study, we examined specific mutations in the helicase that have been shown to regulate its conformation and speed of unwinding. We investigate how these mutations impact the growth, fitness, and cellular morphology of bacteria with the goal of understanding how helicase regulation mechanisms affect an organism’s ability to survive and maintain a stable genome.
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Affiliation(s)
- Megan S. Behrmann
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas, United States of America
| | - Himasha M. Perera
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas, United States of America
| | - Joy M. Hoang
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas, United States of America
| | - Trisha A. Venkat
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas, United States of America
| | - Bryan J. Visser
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - David Bates
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Michael A. Trakselis
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas, United States of America
- * E-mail:
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14
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Aguirre-Sanchez JR, Ibarra-Rodriguez JR, Vega-Lopez IF, Martínez-Urtaza J, Chaidez-Quiroz C. Genomic signatures of adaptation to natural settings in non-typhoidal Salmonella enterica Serovars Saintpaul, Thompson and Weltevreden. INFECTION GENETICS AND EVOLUTION 2021; 90:104771. [PMID: 33592318 DOI: 10.1016/j.meegid.2021.104771] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 02/04/2021] [Accepted: 02/11/2021] [Indexed: 10/22/2022]
Abstract
Salmonella enterica is a pathogenic bacterium responsible for intestinal illness and systemic diseases such as typhoid and paratyphoid fevers. Among clinical manifestation classification, non-typhoidal Salmonella is mainly known as foodborne pathogen associated with the consumption of fecal contaminated food and water. Even though Salmonella hosts include humans and warm-blooded animals, it has been found in non-host environments as river water where the bacteria use different strategies to fitness the environment persisting and establishment. Now with the availability of WGS and bioinformatics tools, we can explore bacterial genomes with higher resolution to increase our understanding of specific genetic signatures among environmental and clinical isolates, being the goal of this work. Pangenome construction allowed the detection of specific environmental and clinical gene clusters related to metabolism and secretion systems as the main signature respectively. Specifically, D-galactonate degradation pathway was observed mainly in environmental genomes while T3SS and flagellum genes were detected for all clinical but not for all environmental isolates. Gene duplication and pseudogenes accumulation were detected as the main adaptation strategy for environmental isolates; thus, isolation source may play an important role in genome plasticity, conferring a selective advantage to survive and persist for environmental Salmonella isolates. Intact prophage sequences with cargo genes were observable for both isolation sources playing an important role in virulence contribution.
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Affiliation(s)
| | | | - I F Vega-Lopez
- Parque de Innovación Tecnológica de la Universidad Autónoma de Sinaloa, Culiacán, Mexico
| | - J Martínez-Urtaza
- Departement of Genetics and Microbiology, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - C Chaidez-Quiroz
- Centro de Investigación en Alimentación y Desarrollo, Culiacán, Mexico.
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15
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Romero ZJ, Chen SH, Armstrong T, Wood EA, van Oijen A, Robinson A, Cox MM. Resolving Toxic DNA repair intermediates in every E. coli replication cycle: critical roles for RecG, Uup and RadD. Nucleic Acids Res 2020; 48:8445-8460. [PMID: 32644157 PMCID: PMC7470958 DOI: 10.1093/nar/gkaa579] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 01/31/2023] Open
Abstract
DNA lesions or other barriers frequently compromise replisome progress. The SF2 helicase RecG is a key enzyme in the processing of postreplication gaps or regressed forks in Escherichia coli. A deletion of the recG gene renders cells highly sensitive to a range of DNA damaging agents. Here, we demonstrate that RecG function is at least partially complemented by another SF2 helicase, RadD. A ΔrecGΔradD double mutant exhibits an almost complete growth defect, even in the absence of stress. Suppressors appear quickly, primarily mutations that compromise priA helicase function or recA promoter mutations that reduce recA expression. Deletions of uup (encoding the UvrA-like ABC system Uup), recO, or recF also suppress the ΔrecGΔradD growth phenotype. RadD and RecG appear to avoid toxic situations in DNA metabolism, either resolving or preventing the appearance of DNA repair intermediates produced by RecA or RecA-independent template switching at stalled forks or postreplication gaps. Barriers to replisome progress that require intervention by RadD or RecG occur in virtually every replication cycle. The results highlight the importance of the RadD protein for general chromosome maintenance and repair. They also implicate Uup as a new modulator of RecG function.
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Affiliation(s)
- Zachary J Romero
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Stefanie H Chen
- Biotechnology Program, North Carolina State University, Raleigh, NC 27695, USA
| | - Thomas Armstrong
- Molecular Horizons Institute and School of Chemistry, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Antoine van Oijen
- Molecular Horizons Institute and School of Chemistry, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Andrew Robinson
- Molecular Horizons Institute and School of Chemistry, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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16
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Wolak C, Ma HJ, Soubry N, Sandler SJ, Reyes-Lamothe R, Keck JL. Interaction with single-stranded DNA-binding protein localizes ribonuclease HI to DNA replication forks and facilitates R-loop removal. Mol Microbiol 2020; 114:495-509. [PMID: 32426857 PMCID: PMC7934204 DOI: 10.1111/mmi.14529] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/30/2020] [Accepted: 05/09/2020] [Indexed: 01/06/2023]
Abstract
DNA replication complexes (replisomes) routinely encounter proteins and unusual nucleic acid structures that can impede their progress. Barriers can include transcription complexes and R-loops that form when RNA hybridizes with complementary DNA templates behind RNA polymerases. Cells encode several RNA polymerase and R-loop clearance mechanisms to limit replisome exposure to these potential obstructions. One such mechanism is hydrolysis of R-loops by ribonuclease HI (RNase HI). Here, we examine the cellular role of the interaction between Escherichia coli RNase HI and the single-stranded DNA-binding protein (SSB) in this process. Interaction with SSB localizes RNase HI foci to DNA replication sites. Mutation of rnhA to encode an RNase HI variant that cannot interact with SSB but that maintains enzymatic activity (rnhAK60E) eliminates RNase HI foci. The mutation also produces a media-dependent slow-growth phenotype and an activated DNA damage response in cells lacking Rep helicase, which is an enzyme that disrupts stalled transcription complexes. RNA polymerase variants that are thought to increase or decrease R-loop accumulation enhance or suppress, respectively, the growth phenotype of rnhAK60E rep::kan strains. These results identify a cellular role for the RNase HI/SSB interaction in helping to clear R-loops that block DNA replication.
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Affiliation(s)
- Christine Wolak
- Department of Biomolecular Chemistry, 420 Henry Mall, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706
| | - Hui Jun Ma
- Department of Biology, McGill University, 3649 Sir William Osler, Montreal, QC, H3G 0B1, Canada
| | - Nicolas Soubry
- Department of Biology, McGill University, 3649 Sir William Osler, Montreal, QC, H3G 0B1, Canada
| | - Steven J. Sandler
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Rodrigo Reyes-Lamothe
- Department of Biology, McGill University, 3649 Sir William Osler, Montreal, QC, H3G 0B1, Canada
| | - James L. Keck
- Department of Biomolecular Chemistry, 420 Henry Mall, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706
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17
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Romero ZJ, Armstrong TJ, Henrikus SS, Chen SH, Glass DJ, Ferrazzoli AE, Wood EA, Chitteni-Pattu S, van Oijen AM, Lovett ST, Robinson A, Cox MM. Frequent template switching in postreplication gaps: suppression of deleterious consequences by the Escherichia coli Uup and RadD proteins. Nucleic Acids Res 2020; 48:212-230. [PMID: 31665437 PMCID: PMC7145654 DOI: 10.1093/nar/gkz960] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 10/03/2019] [Accepted: 10/16/2019] [Indexed: 12/21/2022] Open
Abstract
When replication forks encounter template DNA lesions, the lesion is simply skipped in some cases. The resulting lesion-containing gap must be converted to duplex DNA to permit repair. Some gap filling occurs via template switching, a process that generates recombination-like branched DNA intermediates. The Escherichia coli Uup and RadD proteins function in different pathways to process the branched intermediates. Uup is a UvrA-like ABC family ATPase. RadD is a RecQ-like SF2 family ATPase. Loss of both functions uncovers frequent and RecA-independent deletion events in a plasmid-based assay. Elevated levels of crossing over and repeat expansions accompany these deletion events, indicating that many, if not most, of these events are associated with template switching in postreplication gaps as opposed to simple replication slippage. The deletion data underpin simulations indicating that multiple postreplication gaps may be generated per replication cycle. Both Uup and RadD bind to branched DNAs in vitro. RadD protein suppresses crossovers and Uup prevents nucleoid mis-segregation. Loss of Uup and RadD function increases sensitivity to ciprofloxacin. We present Uup and RadD as genomic guardians. These proteins govern two pathways for resolution of branched DNA intermediates such that potentially deleterious genome rearrangements arising from frequent template switching are averted.
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Affiliation(s)
- Zachary J Romero
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Thomas J Armstrong
- Molecular Horizons Institute and School of Chemistry, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Sarah S Henrikus
- Molecular Horizons Institute and School of Chemistry, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Stefanie H Chen
- Biotechnology Program, North Carolina State University, Raleigh, NC 27695, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - David J Glass
- Department of Biology and Rosenstiel Center, Brandeis University, Waltham, MA 02453, USA
| | - Alexander E Ferrazzoli
- Department of Biology and Rosenstiel Center, Brandeis University, Waltham, MA 02453, USA
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | - Antoine M van Oijen
- Molecular Horizons Institute and School of Chemistry, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Susan T Lovett
- Department of Biology and Rosenstiel Center, Brandeis University, Waltham, MA 02453, USA
| | - Andrew Robinson
- Molecular Horizons Institute and School of Chemistry, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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18
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Abstract
Bacteria frequently encounter low concentrations of antibiotics. Active antibiotics are commonly detected in soil and water at concentrations much below lethal concentration. Although sub-MICs of antibiotics do not kill bacteria, they can have a major impact on bacterial populations by contributing to the development of antibiotic resistance through mutations in originally sensitive bacteria or acquisition of DNA from resistant bacteria. It was shown that concentrations as low as 100-fold below the MIC can actually lead to the selection of antibiotic-resistant cells. We seek to understand how bacterial cells react to such antibiotic concentrations using E. coli, the Gram-negative bacterial paradigm, and V. cholerae, the causative agent of cholera. Our findings shed light on the processes triggered at the DNA level by antibiotics targeting translation, how damage occurs, and what the bacterial strategies are to respond to such DNA damage. We have previously identified Vibrio cholerae mutants in which the stress response to subinhibitory concentrations of aminoglycoside is altered. One gene identified, VC1636, encodes a putative DNA/RNA helicase, recently named RadD in Escherichia coli. Here we combined extensive genetic characterization and high-throughput approaches in order to identify partners and molecular mechanisms involving RadD. We show that double-strand DNA breaks (DSBs) are formed upon subinhibitory tobramycin treatment in the absence of radD and recBCD and that formation of these DSBs can be overcome by RNase H1 overexpression. Loss of RNase H1, or of the transcription-translation coupling factor EF-P, is lethal in the radD deletion mutant. We propose that R-loops are formed upon sublethal aminoglycoside treatment, leading to the formation of DSBs that can be repaired by the RecBCD homologous recombination pathway, and that RadD counteracts such R-loop accumulation. We discuss how R-loops that can occur upon translation-transcription uncoupling could be the link between tobramycin treatment and DNA break formation.
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19
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Kuang X, Tang Q, Liu YP, Yan XX, Xu W. Crystal structure of a novel ATPase RadD from Escherichia coli. Proteins 2019; 87:791-795. [PMID: 31035307 DOI: 10.1002/prot.25704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 04/24/2019] [Accepted: 04/26/2019] [Indexed: 11/07/2022]
Abstract
The helicase superfamily 2 (SF2) proteins are involved in essentially every step in DNA and RNA metabolism. The radD (yejH) gene, which belongs to SF2, plays an important role in DNA repair. The RadD protein includes all seven conserved SF2 motifs and has shown ATPase activity. Here, we first reported the structure of RadD from Escherichia coli containing two RecA-like domains, a zinc finger motif, and a C-terminal domain. Based on the structure of RadD and other SF2 proteins, we then built a model of the RedD-ATP complex.
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Affiliation(s)
- Xiaolin Kuang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People's Republic of China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Qun Tang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Yan-Ping Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Xiao-Xue Yan
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Wenqing Xu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People's Republic of China.,Department of Biological Structure, University of Washington School of Medicine, Seattle, Washington
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20
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Torres R, Serrano E, Tramm K, Alonso JC. Bacillus subtilis RadA/Sms contributes to chromosomal transformation and DNA repair in concert with RecA and circumvents replicative stress in concert with DisA. DNA Repair (Amst) 2019; 77:45-57. [PMID: 30877841 DOI: 10.1016/j.dnarep.2019.03.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 01/15/2019] [Accepted: 03/03/2019] [Indexed: 01/01/2023]
Abstract
Bacillus subtilis radA is epistatic to disA and recA genes in response to methyl methane sulfonate- and 4-nitroquinoline-1-oxide-induced DNA damage. We show that ΔradA cells were sensitive to mitomycin C- and H2O2-induced damage and impaired in natural chromosomal transformation, whereas cells lacking DisA were not. RadA/Sms mutants in the conserved H1 (K104A and K104R) or KNRFG (K255A and K255R) motifs fail to rescue the sensitivity of ΔradA in response to the four different DNA damaging agents. A RadA/Sms H1 or KNRFG mutation impairs both chromosomal and plasmid transformation, but the latter defect was suppressed by inactivating RecA. RadA/Sms K255A, K255R and wild type RadA/Sms reduced the diadenylate cyclase activity of DisA, whereas RadA/Sms K104A and K104R blocked it. Single-stranded and Holliday junction DNA are preferentially bound over double-stranded DNA by RadA/Sms and its variants. Moreover, RadA/Sms ATPase activity was neither stimulated by a variety of DNA substrates nor by DisA. RadA/Sms possesses a 5´→3´ DNA helicase activity. The RadA/Sms mutants neither hydrolyze ATP nor unwind DNA. Thus, we propose that RadA/Sms has two activities: to modulate DisA and to promote RecA-mediated DNA strand exchange. Both activities are required to coordinate responses to replicative stress and genetic recombination.
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Affiliation(s)
- Rubén Torres
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, Darwin Str. 3, 28049 Madrid, Spain
| | - Ester Serrano
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, Darwin Str. 3, 28049 Madrid, Spain
| | - Kristina Tramm
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, Darwin Str. 3, 28049 Madrid, Spain
| | - Juan C Alonso
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, Darwin Str. 3, 28049 Madrid, Spain.
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21
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Cheng K, Wigley DB. DNA translocation mechanism of an XPD family helicase. eLife 2018; 7:42400. [PMID: 30520735 PMCID: PMC6300356 DOI: 10.7554/elife.42400] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/05/2018] [Indexed: 12/21/2022] Open
Abstract
The XPD family of helicases, that includes human disease-related FANCJ, DDX11 and RTEL1, are Superfamily two helicases that contain an iron-sulphur cluster domain, translocate on ssDNA in a 5’−3’ direction and play important roles in genome stability. Consequently, mutations in several of these family members in eukaryotes cause human diseases. Family members in bacteria, such as the DinG helicase from Escherichia coli, are also involved in DNA repair. Here we present crystal structures of complexes of DinG bound to single-stranded DNA (ssDNA) in the presence and absence of an ATP analogue (ADP•BeF3), that suggest a mechanism for 5’−3’ translocation along the ssDNA substrate. This proposed mechanism has implications for how those enzymes of the XPD family that recognise bulky DNA lesions might stall at these as the first step in initiating DNA repair. Biochemical data reveal roles for conserved residues that are mutated in human diseases.
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Affiliation(s)
- Kaiying Cheng
- Section of Structural Biology, Department of Medicine, Imperial College London, London, United Kingdom
| | - Dale B Wigley
- Section of Structural Biology, Department of Medicine, Imperial College London, London, United Kingdom
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22
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Price MN, Wetmore KM, Waters RJ, Callaghan M, Ray J, Liu H, Kuehl JV, Melnyk RA, Lamson JS, Suh Y, Carlson HK, Esquivel Z, Sadeeshkumar H, Chakraborty R, Zane GM, Rubin BE, Wall JD, Visel A, Bristow J, Blow MJ, Arkin AP, Deutschbauer AM. Mutant phenotypes for thousands of bacterial genes of unknown function. Nature 2018; 557:503-509. [PMID: 29769716 DOI: 10.1038/s41586-018-0124-0] [Citation(s) in RCA: 291] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 04/09/2018] [Indexed: 01/25/2023]
Abstract
One-third of all protein-coding genes from bacterial genomes cannot be annotated with a function. Here, to investigate the functions of these genes, we present genome-wide mutant fitness data from 32 diverse bacteria across dozens of growth conditions. We identified mutant phenotypes for 11,779 protein-coding genes that had not been annotated with a specific function. Many genes could be associated with a specific condition because the gene affected fitness only in that condition, or with another gene in the same bacterium because they had similar mutant phenotypes. Of the poorly annotated genes, 2,316 had associations that have high confidence because they are conserved in other bacteria. By combining these conserved associations with comparative genomics, we identified putative DNA repair proteins; in addition, we propose specific functions for poorly annotated enzymes and transporters and for uncharacterized protein families. Our study demonstrates the scalability of microbial genetics and its utility for improving gene annotations.
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Affiliation(s)
- Morgan N Price
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Kelly M Wetmore
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - R Jordan Waters
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Mark Callaghan
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jayashree Ray
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Hualan Liu
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jennifer V Kuehl
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Ryan A Melnyk
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jacob S Lamson
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Yumi Suh
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Hans K Carlson
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Zuelma Esquivel
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Harini Sadeeshkumar
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Romy Chakraborty
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Grant M Zane
- Department of Biochemistry, University of Missouri, Columbia, MO, USA
| | - Benjamin E Rubin
- Division of Biological Sciences, University of California, San Diego, CA, USA
| | - Judy D Wall
- Department of Biochemistry, University of Missouri, Columbia, MO, USA
| | - Axel Visel
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,School of Natural Sciences, University of California, Merced, CA, USA
| | - James Bristow
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Matthew J Blow
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Adam P Arkin
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. .,Department of Bioengineering, University of California, Berkeley, CA, USA.
| | - Adam M Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. .,Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
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23
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Monestier A, Aleksandrov A, Coureux PD, Panvert M, Mechulam Y, Schmitt E. The structure of an E. coli tRNA fMet A 1-U 72 variant shows an unusual conformation of the A 1-U 72 base pair. RNA (NEW YORK, N.Y.) 2017; 23:673-682. [PMID: 28143889 PMCID: PMC5393177 DOI: 10.1261/rna.057877.116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 01/26/2017] [Indexed: 06/06/2023]
Abstract
Translation initiation in eukaryotes and archaea involves a methionylated initiator tRNA delivered to the ribosome in a ternary complex with e/aIF2 and GTP. Eukaryotic and archaeal initiator tRNAs contain a highly conserved A1-U72 base pair at the top of the acceptor stem. The importance of this base pair to discriminate initiator tRNAs from elongator tRNAs has been established previously using genetics and biochemistry. However, no structural data illustrating how the A1-U72 base pair participates in the accurate selection of the initiator tRNAs by the translation initiation systems are available. Here, we describe the crystal structure of a mutant E. coli initiator tRNAfMetA1-U72, aminoacylated with methionine, in which the C1:A72 mismatch at the end of the tRNA acceptor stem has been changed to an A1-U72 base pair. Sequence alignments show that the mutant E. coli tRNA is a good mimic of archaeal initiator tRNAs. The crystal structure, determined at 2.8 Å resolution, shows that the A1-U72 pair adopts an unusual arrangement. A1 is in a syn conformation and forms a single H-bond interaction with U72 This interaction requires protonation of the N1 atom of A1 Moreover, the 5' phosphoryl group folds back into the major groove of the acceptor stem and interacts with the N7 atom of G2 A possible role of this unusual geometry of the A1-U72 pair in the recognition of the initiator tRNA by its partners during eukaryotic and archaeal translation initiation is discussed.
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Affiliation(s)
- Auriane Monestier
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau cedex, France
| | - Alexey Aleksandrov
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau cedex, France
| | - Pierre-Damien Coureux
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau cedex, France
| | - Michel Panvert
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau cedex, France
| | - Yves Mechulam
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau cedex, France
| | - Emmanuelle Schmitt
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau cedex, France
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24
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Chen SH, Byrne-Nash RT, Cox MM. Escherichia coli RadD Protein Functionally Interacts with the Single-stranded DNA-binding Protein. J Biol Chem 2016; 291:20779-86. [PMID: 27519413 DOI: 10.1074/jbc.m116.736223] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Indexed: 11/06/2022] Open
Abstract
The bacterial single-stranded DNA binding protein (SSB) acts as an organizer of DNA repair complexes. The radD gene was recently identified as having an unspecified role in repair of radiation damage and, more specifically, DNA double-strand breaks. Purified RadD protein displays a DNA-independent ATPase activity. However, ATP hydrolytic rates are stimulated by SSB through its C terminus. The RadD and SSB proteins also directly interact in vivo in a yeast two-hybrid assay and in vitro through ammonium sulfate co-precipitation. Therefore, it is likely that the repair function of RadD is mediated through interaction with SSB at the site of damage.
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Affiliation(s)
- Stefanie H Chen
- From the Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Rose T Byrne-Nash
- From the Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Michael M Cox
- From the Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
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25
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Sprouffske K, Aguilar-Rodríguez J, Wagner A. How Archiving by Freezing Affects the Genome-Scale Diversity of Escherichia coli Populations. Genome Biol Evol 2016; 8:1290-8. [PMID: 26988250 PMCID: PMC4898790 DOI: 10.1093/gbe/evw054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In the experimental evolution of microbes such as Escherichia coli, many replicate populations are evolved from a common ancestor. Freezing a population sample supplemented with the cryoprotectant glycerol permits later analysis or restarting of an evolution experiment. Typically, each evolving population, and thus each sample archived in this way, consists of many unique genotypes and phenotypes. The effect of archiving on such a heterogeneous population is unknown. Here, we identified optimal archiving conditions for E. coli. We also used genome sequencing of archived samples to study the effects that archiving has on genomic population diversity. We observed no allele substitutions and mostly small changes in allele frequency. Nevertheless, principal component analysis of genome-scale allelic diversity shows that archiving affects diversity across many loci. We showed that this change in diversity is due to selection rather than drift. In addition, ∼1% of rare alleles that occurred at low frequencies were lost after treatment. Our observations imply that archived populations may be used to conduct fitness or other phenotypic assays of populations, in which the loss of a rare allele may have negligible effects. However, caution is appropriate when sequencing populations restarted from glycerol stocks, as well as when using glycerol stocks to restart or replay evolution. This is because the loss of rare alleles can alter the future evolutionary trajectory of a population if the lost alleles were strongly beneficial.
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Affiliation(s)
- Kathleen Sprouffske
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - José Aguilar-Rodríguez
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Andreas Wagner
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland Swiss Institute of Bioinformatics, Lausanne, Switzerland The Santa Fe Institute, Santa Fe, NM, USA
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26
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Ronayne EA, Wan YCS, Boudreau BA, Landick R, Cox MM. P1 Ref Endonuclease: A Molecular Mechanism for Phage-Enhanced Antibiotic Lethality. PLoS Genet 2016; 12:e1005797. [PMID: 26765929 PMCID: PMC4713147 DOI: 10.1371/journal.pgen.1005797] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 12/19/2015] [Indexed: 12/11/2022] Open
Abstract
Ref is an HNH superfamily endonuclease that only cleaves DNA to which RecA protein is bound. The enigmatic physiological function of this unusual enzyme is defined here. Lysogenization by bacteriophage P1 renders E. coli more sensitive to the DNA-damaging antibiotic ciprofloxacin, an example of a phenomenon termed phage-antibiotic synergy (PAS). The complementary effect of phage P1 is uniquely traced to the P1-encoded gene ref. Ref is a P1 function that amplifies the lytic cycle under conditions when the bacterial SOS response is induced due to DNA damage. The effect of Ref is multifaceted. DNA binding by Ref interferes with normal DNA metabolism, and the nuclease activity of Ref enhances genome degradation. Ref also inhibits cell division independently of the SOS response. Ref gene expression is toxic to E. coli in the absence of other P1 functions, both alone and in combination with antibiotics. The RecA proteins of human pathogens Neisseria gonorrhoeae and Staphylococcus aureus serve as cofactors for Ref-mediated DNA cleavage. Ref is especially toxic during the bacterial SOS response and the limited growth of stationary phase cultures, targeting aspects of bacterial physiology that are closely associated with the development of bacterial pathogen persistence.
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Affiliation(s)
- Erin A. Ronayne
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Y. C. Serena Wan
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Beth A. Boudreau
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Michael M. Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
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