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Kozlova S, Morozova N, Ispolatov Y, Severinov K. Dependence of post-segregational killing mediated by Type II restriction-modification systems on the lifetime of restriction endonuclease effective activity. mBio 2024:e0140824. [PMID: 38980007 DOI: 10.1128/mbio.01408-24] [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: 05/14/2024] [Accepted: 06/10/2024] [Indexed: 07/10/2024] Open
Abstract
Plasmid-borne Type II restriction-modification (RM) systems mediate post-segregational killing (PSK). PSK is thought to be caused by the dilution of restriction and modification enzymes during cell division, resulting in accumulation of unmethylated DNA recognition sites and their cleavage by restriction endonucleases. PSK is the likely reason for stabilization of plasmids carrying RM systems in the absence of selection for plasmid maintenance. In this study, we developed a CRISPR interference-based method to eliminate RM-carrying plasmids and study PSK-related phenomena with minimal perturbation to the Escherichia coli host. Plasmids carrying the EcoRV, Eco29kI, and EcoRI RM systems were highly stable, and their loss resulted in SOS response and PSK. In contrast, plasmids carrying the Esp1396I system were poorly stabilized; their loss led to a temporary cessation of growth, followed by full recovery. We demonstrate that this unusual behavior is due to a limited lifetime of the Esp1396I restriction endonuclease activity, which, upon Esp1396I plasmid loss, disappears approximately after two cycles of cell division, i.e., before unmethylated sites appear in significant numbers. Our results indicate that whenever PSK induced by a loss of RM systems, and, possibly, other toxin-antitoxin systems, is considered, the lifetimes of individual system components and the growth rate of host cells shall be taken in account. Mathematical modeling shows, that unlike the situation with classical toxin-antitoxin systems, RM system-mediated PSK is possible when the lifetimes of restriction endonuclease and methyltransferase activities are similar, as long as the toxic restriction endonuclease activity persists for more than two chromosome replication cycles.IMPORTANCEIt is widely accepted that many Type II restriction-modification (RM) systems mediate post-segregational killing (PSK) if plasmids that encode them are lost. In this study, we harnessed an inducible CRISPR-Cas system to remove RM plasmids from Escherichia coli cells to study PSK while minimally perturbing cell physiology. We demonstrate that PSK depends on restriction endonuclease activity lifetime and is not observed when it is less than two replication cycles. We present a mathematical model that explains experimental data and shows that unlike the case of toxin-antitoxin-mediated PSK, the loss of an RM system induced PSK even when the RM enzymes have identical lifetimes.
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Affiliation(s)
- Svetlana Kozlova
- Skolkovo Institute of Science and Technology, Center for Molecular and Cellular Biology, Moscow, Russia
| | - Natalia Morozova
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Yaroslav Ispolatov
- Physics Department, University of Santiago of Chile, Center for Interdisciplinary Research in Astrophysics and Space Science, Santiago, Chile
| | - Konstantin Severinov
- Waksman Institute for Microbiology and Department of Molecular Biology and Biochemistry, Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
- Institute of Gene Biology, Moscow, Russia
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2
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Zahradka K, Repar J, Đermić D, Zahradka D. Chromosome Segregation and Cell Division Defects in Escherichia coli Recombination Mutants Exposed to Different DNA-Damaging Treatments. Microorganisms 2023; 11:microorganisms11030701. [PMID: 36985274 PMCID: PMC10051365 DOI: 10.3390/microorganisms11030701] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 03/05/2023] [Indexed: 03/30/2023] Open
Abstract
Homologous recombination repairs potentially lethal DNA lesions such as double-strand DNA breaks (DSBs) and single-strand DNA gaps (SSGs). In Escherichia coli, DSB repair is initiated by the RecBCD enzyme that resects double-strand DNA ends and loads RecA recombinase to the emerging single-strand (ss) DNA tails. SSG repair is mediated by the RecFOR protein complex that loads RecA onto the ssDNA segment of gaped duplex. In both repair pathways, RecA catalyses reactions of homologous DNA pairing and strand exchange, while RuvABC complex and RecG helicase process recombination intermediates. In this work, we have characterised cytological changes in various recombination mutants of E. coli after three different DNA-damaging treatments: (i) expression of I-SceI endonuclease, (ii) γ-irradiation, and (iii) UV-irradiation. All three treatments caused severe chromosome segregation defects and DNA-less cell formation in the ruvABC, recG, and ruvABC recG mutants. After I-SceI expression and γ-irradiation, this phenotype was efficiently suppressed by the recB mutation, indicating that cytological defects result mostly from incomplete DSB repair. In UV-irradiated cells, the recB mutation abolished cytological defects of recG mutants and also partially suppressed the cytological defects of ruvABC recG mutants. However, neither recB nor recO mutation alone could suppress the cytological defects of UV-irradiated ruvABC mutants. The suppression was achieved only by simultaneous inactivation of the recB and recO genes. Cell survival and microscopic analysis suggest that chromosome segregation defects in UV-irradiated ruvABC mutants largely result from defective processing of stalled replication forks. The results of this study show that chromosome morphology is a valuable marker in genetic analyses of recombinational repair in E. coli.
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Affiliation(s)
- Ksenija Zahradka
- Laboratory for Molecular Microbiology, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Jelena Repar
- Laboratory for Molecular Microbiology, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Damir Đermić
- Laboratory for Molecular Microbiology, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Davor Zahradka
- Laboratory for Molecular Microbiology, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
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He D, Du Z, Xu H, Bao X. Chl1, an ATP-Dependent DNA Helicase, Inhibits DNA:RNA Hybrids Formation at DSB Sites to Maintain Genome Stability in S. pombe. Int J Mol Sci 2022; 23:ijms23126631. [PMID: 35743069 PMCID: PMC9224301 DOI: 10.3390/ijms23126631] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/03/2022] [Accepted: 06/10/2022] [Indexed: 02/01/2023] Open
Abstract
As an ATP-dependent DNA helicase, human ChlR1/DDX11 (Chl1 in yeast) can unwind both DNA:RNA and DNA:DNA substrates in vitro. Studies have demonstrated that ChlR1 plays a vital role in preserving genome stability by participating in DNA repair and sister chromatid cohesion, whereas the ways in which the biochemical features of ChlR1 function in DNA metabolism are not well understood. Here, we illustrate that Chl1 localizes to double-strand DNA break (DSB) sites and restrains DNA:RNA hybrid accumulation at these loci. Mutation of Chl1 strongly impairs DSB repair capacity by homologous recombination (HR) and nonhomologous end-joining (NHEJ) pathways, and deleting RNase H further reduces DNA repair efficiency, which indicates that the enzymatic activities of Chl1 are needed in Schizosaccharomyces pombe. In addition, we found that the Rpc37 subunit of RNA polymerase III (RNA Pol III) interacts directly with Chl1 and that deletion of Chl1 has no influence on the localization of Rpc37 at DSB site, implying the role of Rpc37 in the recruitment of Chl1 to this site.
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Affiliation(s)
- Deyun He
- State Key Laboratory of Biobased Material and Green Papermaking, School of Bioengineering, Qilu University of Technology, Jinan 250353, China; (Z.D.); (H.X.)
- Key Laboratory of Shandong Microbial Engineering, Shandong Academy of Sciences, Qilu University of Technology, Jinan 250353, China
- Correspondence: (D.H.); (X.B.)
| | - Zhen Du
- State Key Laboratory of Biobased Material and Green Papermaking, School of Bioengineering, Qilu University of Technology, Jinan 250353, China; (Z.D.); (H.X.)
- Key Laboratory of Shandong Microbial Engineering, Shandong Academy of Sciences, Qilu University of Technology, Jinan 250353, China
| | - Huiling Xu
- State Key Laboratory of Biobased Material and Green Papermaking, School of Bioengineering, Qilu University of Technology, Jinan 250353, China; (Z.D.); (H.X.)
- Key Laboratory of Shandong Microbial Engineering, Shandong Academy of Sciences, Qilu University of Technology, Jinan 250353, China
| | - Xiaoming Bao
- State Key Laboratory of Biobased Material and Green Papermaking, School of Bioengineering, Qilu University of Technology, Jinan 250353, China; (Z.D.); (H.X.)
- Key Laboratory of Shandong Microbial Engineering, Shandong Academy of Sciences, Qilu University of Technology, Jinan 250353, China
- Correspondence: (D.H.); (X.B.)
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4
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Harami GM, Pálinkás J, Seol Y, Kovács ZJ, Gyimesi M, Harami-Papp H, Neuman KC, Kovács M. The toposiomerase IIIalpha-RMI1-RMI2 complex orients human Bloom's syndrome helicase for efficient disruption of D-loops. Nat Commun 2022; 13:654. [PMID: 35115525 PMCID: PMC8813930 DOI: 10.1038/s41467-022-28208-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 01/12/2022] [Indexed: 01/05/2023] Open
Abstract
Homologous recombination (HR) is a ubiquitous and efficient process that serves the repair of severe forms of DNA damage and the generation of genetic diversity during meiosis. HR can proceed via multiple pathways with different outcomes that may aid or impair genome stability and faithful inheritance, underscoring the importance of HR quality control. Human Bloom's syndrome (BLM, RecQ family) helicase plays central roles in HR pathway selection and quality control via unexplored molecular mechanisms. Here we show that BLM's multi-domain structural architecture supports a balance between stabilization and disruption of displacement loops (D-loops), early HR intermediates that are key targets for HR regulation. We find that this balance is markedly shifted toward efficient D-loop disruption by the presence of BLM's interaction partners Topoisomerase IIIα-RMI1-RMI2, which have been shown to be involved in multiple steps of HR-based DNA repair. Our results point to a mechanism whereby BLM can differentially process D-loops and support HR control depending on cellular regulatory mechanisms.
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Affiliation(s)
- Gábor M Harami
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117, Budapest, Hungary. .,Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA.
| | - János Pálinkás
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117, Budapest, Hungary
| | - Yeonee Seol
- Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - Zoltán J Kovács
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117, Budapest, Hungary
| | - Máté Gyimesi
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117, Budapest, Hungary.,MTA-ELTE Motor Pharmacology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117, Budapest, Hungary
| | - Hajnalka Harami-Papp
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117, Budapest, Hungary.,Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - Keir C Neuman
- Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - Mihály Kovács
- ELTE-MTA "Momentum" Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117, Budapest, Hungary. .,MTA-ELTE Motor Pharmacology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117, Budapest, Hungary.
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5
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Racharaks R, Arnold W, Peccia J. Development of CRISPR-Cas9 knock-in tools for free fatty acid production using the fast-growing cyanobacterial strain Synechococcus elongatus UTEX 2973. J Microbiol Methods 2021; 189:106315. [PMID: 34454980 DOI: 10.1016/j.mimet.2021.106315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/23/2021] [Accepted: 08/23/2021] [Indexed: 12/26/2022]
Abstract
Synechococcus elongatus UTEX 2973 has one of the fastest measured doubling time of cyanobacteria making it an important candidate for metabolic engineering. Traditional genetic engineering methods, which rely on homologous recombination, however, are inefficient, labor-intensive, and time-consuming due to the oligoploidy or polyploidy nature of cyanobacteria and the reliance on unique antibiotic resistance markers. CRISPR-Cas9 has emerged as an effective and versatile editing platform in a wide variety of organisms, but its application for cyanobacterial engineering is limited by the inherent toxicity of Cas9 resulting in poor transformation efficiencies. Here, we demonstrated that a single-plasmid CRISPR-Cas9 system, pCRISPOmyces-2, can effectively knock-in a truncated thioesterase gene from Escherichia coli to generate free fatty acid (FFA) producing mutants of Syn2973. To do so, three parameters were evaluated on the effect of generating recipient colonies after conjugation with pCRISPOmyces-2-based plasmids: 1) a modified conjugation protocol termed streaked conjugation, 2) the deletion of the gene encoding RecJ exonuclease, and 3) single guide RNA (sgRNA) sequence. With the use of the streaked conjugation protocol and a ΔrecJ mutant strain of Syn2973, the conjugation efficiency for the pCRISPomyces-2 plasmid could be improved by 750-fold over the wildtype (WT) for a conjugation efficiency of 2.0 × 10-6 transconjugants/recipient cell. While deletion of the RecJ exonuclease alone increased the conjugation efficiency by 150-fold over the WT, FFA generation was impaired in FFA-producing mutants with the ΔrecJ background, and the large number of poor FFA-producing isolates indicated the potential increase in spontaneous mutation rates. The sgRNA sequence was found to be critical in achieving the desired CRISPR-Cas9-mediated knock-in mutation as the sgRNA impacts conjugation efficiency, likelihood of homogenous recombinants, and free fatty acid production in engineered strains.
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Affiliation(s)
- Ratanachat Racharaks
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, USA
| | - Wyatt Arnold
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, USA
| | - Jordan Peccia
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, USA.
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6
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Genetic Analysis of DinG Family Helicase YoaA and Its Interaction with Replication Clamp Loader Protein HolC in Escherichia coli. J Bacteriol 2021; 203:e0022821. [PMID: 34181484 PMCID: PMC8378479 DOI: 10.1128/jb.00228-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The XP-D/DinG family of DNA helicases contributes to genomic stability in all three domains of life. Here, we investigate the role of one of these proteins, YoaA, of Escherichia coli. In E. coli, YoaA aids in tolerance to the nucleoside azidothymidine (AZT), a DNA replication inhibitor, and physically interacts with a subunit of the DNA polymerase III holoenzyme, HolC. We map the residues of YoaA required for HolC interaction to its C terminus by yeast two-hybrid analysis. We propose that this interaction competes with HolC’s interaction with HolD and the rest of the replisome; YoaA indeed inhibits growth when overexpressed, dependent on this interaction region. By gene fusions, we show that YoaA is repressed by LexA and induced in response to DNA damage as part of the SOS response. Induction of YoaA by AZT is biphasic, with an immediate response after treatment and a slower response that peaks in the late log phase of growth. This growth-phase-dependent induction by AZT is not blocked by lexA3 (Ind−), which normally negates its self-cleavage, implying another means to induce the DNA damage response that responds to the nutritional state of the cell. We propose that YoaA helicase activity increases access to the 3′ nascent strand during replication; consistent with this, YoaA appears to aid in the removal of potential A-to-T transversion mutations in ndk mutants, which are prone to nucleotide misincorporation. We provide evidence that YoaA and its paralog DinG may also initiate template switching that leads to deletions between tandem repeats in DNA. IMPORTANCE Maintaining genomic stability is crucial for all living organisms. Replication of DNA frequently encounters barriers that must be removed to complete genome duplication. Balancing DNA synthesis with its repair is critical and not entirely understood at a mechanistic level. The YoaA protein, studied here, is required for certain types of DNA repair and interacts in an alternative manner with proteins that catalyze DNA replication. YoaA is part of the well-studied LexA-regulated response to DNA damage, the SOS response. We describe an unusual feature of its regulation that promotes induction after DNA damage as the culture begins to experience starvation. Replication fork repair integrates both DNA damage and nutritional signals. We also show that YoaA affects genomic stability.
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7
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Klaric JA, Glass DJ, Perr EL, Reuven AD, Towne MJ, Lovett ST. DNA damage-signaling, homologous recombination and genetic mutation induced by 5-azacytidine and DNA-protein crosslinks in Escherichia coli. Mutat Res 2021; 822:111742. [PMID: 33743507 DOI: 10.1016/j.mrfmmm.2021.111742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 02/01/2021] [Accepted: 03/08/2021] [Indexed: 11/29/2022]
Abstract
Covalent linkage between DNA and proteins produces highly toxic lesions and can be caused by commonly used chemotherapeutic agents, by internal and external chemicals and by radiation. In this study, using Escherichia coli, we investigate the consequences of 5-azacytidine (5-azaC), which traps covalent complexes between itself and the Dcm cytosine methyltransferase protein. DNA protein crosslink-dependent effects can be ascertained by effects that arise in wild-type but not in dcmΔ strains. We find that 5-azaC induces the bacterial DNA damage response and stimulates homologous recombination, a component of which is Dcm-dependent. Template-switching at an imperfect inverted repeat ("quasipalindrome", QP) is strongly enhanced by 5-azaC and this enhancement was entirely Dcm-dependent and independent of double-strand break repair. The SOS response helps ameliorate the mutagenic effect of 5-azaC but this is not a result of SOS-induced DNA polymerases since their induction, especially PolIV, seems to stimulate QP-associated mutagenesis. Cell division regulator SulA was also required for recovery of QP mutants induced by 5-azaC. In the absence of Lon protease, Dcm-dependent QP-mutagenesis is strongly elevated, suggesting it may play a role in DPC tolerance. Deletions at short tandem repeats, which occur likewise by a replication template-switch, are elevated, but only modestly, by 5-azaC. We see evidence for Dcm-dependent and-independent killing by 5-azaC in sensitive mutants, such as recA, recB, and lon; homologous recombination and deletion mutations are also stimulated in part by a Dcm-independent effect of 5-azaC. Whether this occurs by a different protein/DNA crosslink or by an alternative form of DNA damage is unknown.
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Affiliation(s)
- Julie A Klaric
- Department of Biology and Rosentiel Basic Medical Sciences Research Center Brandeis University, Waltham, MA, 02454-9110, United States
| | - David J Glass
- Department of Biology and Rosentiel Basic Medical Sciences Research Center Brandeis University, Waltham, MA, 02454-9110, United States
| | - Eli L Perr
- Department of Biology and Rosentiel Basic Medical Sciences Research Center Brandeis University, Waltham, MA, 02454-9110, United States
| | - Arianna D Reuven
- Department of Biology and Rosentiel Basic Medical Sciences Research Center Brandeis University, Waltham, MA, 02454-9110, United States
| | - Mason J Towne
- Department of Biology and Rosentiel Basic Medical Sciences Research Center Brandeis University, Waltham, MA, 02454-9110, United States
| | - Susan T Lovett
- Department of Biology and Rosentiel Basic Medical Sciences Research Center Brandeis University, Waltham, MA, 02454-9110, United States.
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8
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Liu S, Hua Y, Wang J, Li L, Yuan J, Zhang B, Wang Z, Ji J, Kong D. RNA polymerase III is required for the repair of DNA double-strand breaks by homologous recombination. Cell 2021; 184:1314-1329.e10. [PMID: 33626331 DOI: 10.1016/j.cell.2021.01.048] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 09/24/2020] [Accepted: 01/26/2021] [Indexed: 12/22/2022]
Abstract
End resection in homologous recombination (HR) and HR-mediated repair of DNA double-strand breaks (DSBs) removes several kilobases from 5' strands of DSBs, but 3' strands are exempted from degradation. The mechanism by which the 3' overhangs are protected has not been determined. Here, we established that the protection of 3' overhangs is achieved through the transient formation of RNA-DNA hybrids. The DNA strand in the hybrids is the 3' ssDNA overhang, while the RNA strand is newly synthesized. RNA polymerase III (RNAPIII) is responsible for synthesizing the RNA strand. Furthermore, RNAPIII is actively recruited to DSBs by the MRN complex. CtIP and MRN nuclease activity is required for initiating the RNAPIII-mediated RNA synthesis at DSBs. A reduced level of RNAPIII suppressed HR, and genetic loss > 30 bp increased at DSBs. Thus, RNAPIII is an essential HR factor, and the RNA-DNA hybrid is an essential repair intermediate for protecting the 3' overhangs in DSB repair.
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Affiliation(s)
- Sijie Liu
- Peking-Tsinghua Center for Life Sciences, The National Laboratory of Protein and Plant Gene research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Yu Hua
- Peking-Tsinghua Center for Life Sciences, The National Laboratory of Protein and Plant Gene research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Jingna Wang
- Peking-Tsinghua Center for Life Sciences, The National Laboratory of Protein and Plant Gene research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Lingyan Li
- Peking-Tsinghua Center for Life Sciences, The National Laboratory of Protein and Plant Gene research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Junjie Yuan
- Peking-Tsinghua Center for Life Sciences, The National Laboratory of Protein and Plant Gene research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Bo Zhang
- Peking-Tsinghua Center for Life Sciences, The National Laboratory of Protein and Plant Gene research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Ziyang Wang
- Peking-Tsinghua Center for Life Sciences, The National Laboratory of Protein and Plant Gene research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Jianguo Ji
- Peking-Tsinghua Center for Life Sciences, The National Laboratory of Protein and Plant Gene research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Daochun Kong
- Peking-Tsinghua Center for Life Sciences, The National Laboratory of Protein and Plant Gene research, College of Life Sciences, Peking University, Beijing 100871, China.
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Gamma irradiation triggers a global stress response in Escherichia coli O157:H7 including base and nucleotides excision repair pathways. Microb Pathog 2020; 149:104342. [PMID: 32534179 DOI: 10.1016/j.micpath.2020.104342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/04/2020] [Accepted: 06/05/2020] [Indexed: 11/21/2022]
Abstract
Shiga toxin-producing Escherichia coli O157:H7, one of the most severe human foodborne pathogens, can withstand several stresses, including some levels of γ-irradiation. In this study, the response of E. coli O157:H7 to a sensitization irradiation dose of 0.4 kGy was assessed using RNA-seq transcriptomic at 10 (t10) and 60 (t60) min post-irradiation, combined with an isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis at 60 min post-irradiation. Several functions were induced by the treatment, such as base excision repair and nucleotide excision repair pathways; sulfur and histidine metabolism, and virulence mechanisms. Additionally, the sulA gene, coding for the cell division repressor, together with other genes involved in SOS response and repair mechanism (including recA, recN, recJ, recQ, mutM and uvrB) were up-regulated at t60. As the early response to irradiation stress (t10), dnaK, groEL, ibpA, sulfur metabolism genes, as well as those related to oxidative stress were up-regulated, while histidine biosynthesis genes were down-regulated. Acid stress, heat shock, UV resistance and several virulence genes, especially stx2A/stx2b which code for the Shiga toxins characteristic of O157:H7, were upregulated at 60 min post-irradiation. The treatment was also found to increase the levels of CysN, MutM, DinG and DnaC in the cells, proteins involved respectively in sulfur metabolism, base excision repair, recombinational DNA repair and chromosome replication. Our results provide insights into the resistance response of E. coli O157:H7 to a non-lethal irradiation dose. Our findings indicate that E. coli O157:H7 can resist to γ-irradiation through important modifications in genes expression and proteins profiles.
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Ding T, Huang C, Liang Z, Ma X, Wang N, Huo YX. Reversed paired-gRNA plasmid cloning strategy for efficient genome editing in Escherichia coli. Microb Cell Fact 2020; 19:63. [PMID: 32156270 PMCID: PMC7063769 DOI: 10.1186/s12934-020-01321-4] [Citation(s) in RCA: 7] [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: 12/06/2019] [Accepted: 03/01/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Co-expression of two distinct guide RNAs (gRNAs) has been used to facilitate the application of CRISPR/Cas9 system in fields such as large genomic deletion. The paired gRNAs are often placed adjacently in the same direction and expressed individually by two identical promoters, constituting direct repeats (DRs) which are susceptible to self-homologous recombination. As a result, the paired-gRNA plasmids cannot remain stable, which greatly prevents extensible applications of CRISPR/Cas9 system. RESULTS To address this limitation, different DRs-involved paired-gRNA plasmids were designed and the events of recombination were characterized. Deletion between DRs occurred with high frequencies during plasmid construction and subsequent plasmid propagation. This recombination event was RecA-independent, which agreed with the replication slippage model. To increase plasmid stability, a reversed paired-gRNA plasmids (RPGPs) cloning strategy was developed by converting DRs to the more stable invert repeats (IRs), which completely eliminated DRs-induced recombination. Using RPGPs, rapid deletion of chromosome fragments up to 100 kb with an efficiency of 83.33% was achieved in Escherichia coli. CONCLUSIONS The RPGPs cloning strategy serves as a general solution to avoid plasmid RecA-independent recombination. It can be adapted to applications that rely on paired gRNAs or repeated genetic parts.
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Affiliation(s)
- Tingting Ding
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Sciences, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, Beijing, 100081, China
- SIP-UCLA Institute for Technology Advancement, Suzhou, 215123, China
| | - Chaoyong Huang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Sciences, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, Beijing, 100081, China
| | - Zeyu Liang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Sciences, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, Beijing, 100081, China
| | - Xiaoyan Ma
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Sciences, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, Beijing, 100081, China.
| | - Ning Wang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Sciences, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, Beijing, 100081, China.
| | - Yi-Xin Huo
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Sciences, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, Beijing, 100081, China
- SIP-UCLA Institute for Technology Advancement, Suzhou, 215123, China
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11
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Romero H, Serrano E, Hernández-Tamayo R, Carrasco B, Cárdenas PP, Ayora S, Graumann PL, Alonso JC. Bacillus subtilis RarA Acts as a Positive RecA Accessory Protein. Front Microbiol 2020; 11:92. [PMID: 32117122 PMCID: PMC7031210 DOI: 10.3389/fmicb.2020.00092] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 01/16/2020] [Indexed: 01/15/2023] Open
Abstract
Ubiquitous RarA AAA+ ATPases play crucial roles in the cellular response to blocked replication forks in pro- and eukaryotes. Here, we provide evidence that absence of RarA reduced the viability of ΔrecA, ΔrecO, and recF15 cells during unperturbed growth. The rarA gene was epistatic to recO and recF genes in response to H2O2- or MMS-induced DNA damage. Conversely, the inactivation of rarA partially suppressed the HR defect of mutants lacking end-resection (ΔaddAB, ΔrecJ, ΔrecQ, ΔrecS) or branch migration (ΔruvAB, ΔrecG, ΔradA) activity. RarA contributes to RecA thread formation, that are thought to be the active forms of RecA during homology search. The absence of RarA reduced RecA accumulation, and the formation of visible RecA threads in vivo upon DNA damage. When ΔrarA was combined with mutations in genuine RecA accessory genes, RecA accumulation was further reduced in ΔrarA ΔrecU and ΔrarA ΔrecX double mutant cells, and was blocked in ΔrarA recF15 cells. These results suggest that RarA contributes to the assembly of RecA nucleoprotein filaments onto single-stranded DNA, and possibly antagonizes RecA filament disassembly.
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Affiliation(s)
- Hector Romero
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
- SYNMIKRO, LOEWE-Zentrum für Synthetische Mikrobiologie, Marburg, Germany
- Fachbereich Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Ester Serrano
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Rogelio Hernández-Tamayo
- SYNMIKRO, LOEWE-Zentrum für Synthetische Mikrobiologie, Marburg, Germany
- Fachbereich Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Begoña Carrasco
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Paula P. Cárdenas
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Silvia Ayora
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Peter L. Graumann
- SYNMIKRO, LOEWE-Zentrum für Synthetische Mikrobiologie, Marburg, Germany
- Fachbereich Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Juan C. Alonso
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
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12
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Lawarée E, Jankevicius G, Cooper C, Ahel I, Uphoff S, Tang CM. DNA ADP-Ribosylation Stalls Replication and Is Reversed by RecF-Mediated Homologous Recombination and Nucleotide Excision Repair. Cell Rep 2020; 30:1373-1384.e4. [PMID: 32023456 PMCID: PMC7003065 DOI: 10.1016/j.celrep.2020.01.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 10/16/2019] [Accepted: 01/02/2020] [Indexed: 01/08/2023] Open
Abstract
ADP-ribosylation of proteins is crucial for fundamental cellular processes. Despite increasing examples of DNA ADP-ribosylation, the impact of this modification on DNA metabolism and cell physiology is unknown. Here, we show that the DarTG toxin-antitoxin system from enteropathogenic Escherichia coli (EPEC) catalyzes reversible ADP-ribosylation of single-stranded DNA (ssDNA). The DarT toxin recognizes specific sequence motifs. EPEC DarG abrogates DarT toxicity by two distinct mechanisms: removal of DNA ADP-ribose (ADPr) groups and DarT sequestration. Furthermore, we investigate how cells recognize and deal with DNA ADP-ribosylation. We demonstrate that DNA ADPr stalls replication and is perceived as DNA damage. Removal of ADPr from DNA requires the sequential activity of two DNA repair pathways, with RecF-mediated homologous recombination likely to transfer ADP-ribosylation from single- to double-stranded DNA (dsDNA) and subsequent nucleotide excision repair eliminating the lesion. Our work demonstrates that these DNA repair pathways prevent the genotoxic effects of DNA ADP-ribosylation.
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Affiliation(s)
- Emeline Lawarée
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Gytis Jankevicius
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Charles Cooper
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Stephan Uphoff
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Christoph M Tang
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
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13
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Abstract
In light of the rising prevalence of antimicrobial resistance (AMR) and the slow pace of new antimicrobial development, there has been increasing interest in the development of adjuvants that improve or restore the effectiveness of existing drugs. Here, we use a novel small RNA (sRNA) screening approach to identify genes whose knockdown increases ciprofloxacin (CIP) sensitivity in a resistant strain of Escherichia coli 5000 sRNA constructs were initially screened on a gyrA S83L background, ultimately leading to 30 validated genes whose disruption reduces CIP resistance. This set includes genes involved in DNA replication, repair, recombination, efflux, and other regulatory systems. Our findings increase understanding of the functional interactions of DNA Gyrase, and may aid in the development of new therapeutic approaches for combating AMR.
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14
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Integration Host Factor IHF facilitates homologous recombination and mutagenic processes in Pseudomonas putida. DNA Repair (Amst) 2019; 85:102745. [PMID: 31715424 DOI: 10.1016/j.dnarep.2019.102745] [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] [Received: 07/19/2019] [Revised: 10/25/2019] [Accepted: 10/31/2019] [Indexed: 12/14/2022]
Abstract
Nucleoid-associated proteins (NAPs) such as IHF, HU, Fis, and H-NS alter the topology of bound DNA and may thereby affect accessibility of DNA to repair and recombination processes. To examine this possibility, we investigated the effect of IHF on the frequency of homologous recombination (HR) and point mutations in soil bacterium Pseudomonas putida by using plasmidial and chromosomal assays. We observed positive effect of IHF on the frequency of HR, whereas this effect varied depending both on the chromosomal location of the HR target and the type of plasmid used in the assay. The occurrence of point mutations in plasmid was also facilitated by IHF, whereas in the chromosome the positive effect of IHF appeared only at certain DNA sequences and/or chromosomal positions. We did not observe any significant effects of IHF on the spectrum of mutations. However, despite of the presence or absence of IHF, different mutational hot spots appeared both in plasmid and in chromosome. Additionally, the frequency of frameshift mutations in the chromosome was also strongly affected by the location of the mutational target sequence. Taking together, our results indicate that IHF facilitates the occurrence of genetic changes in P. putida, whereas the location of the target sequence affects both the IHF-dependent and IHF-independent mechanisms.
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15
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DNA double-strand break formation and repair as targets for novel antibiotic combination chemotherapy. Future Sci OA 2019; 5:FSO411. [PMID: 31534779 PMCID: PMC6745595 DOI: 10.2144/fsoa-2019-0034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
An unrepaired DNA double-strand break (DSB) is lethal to cells. In bacteria, DSBs are usually repaired either via an error-prone pathway, which ligates the ends of the break or an accurate recombination pathway. Due to this lethality, drugs that induce persistent DSBs have been successful in bacterial infection treatment. However, recurrent usage of these drugs has led to emergence of resistant strains. Several articles have thoroughly reviewed the causes, mechanisms and effects of bacterial drug resistance while others have also discussed approaches for facilitating drug discovery and development. Here, we focus on a hypothetical chemotherapeutic strategy that can be explored for minimizing development of resistance to novel DSB-inducing compounds. We also highlight the possibility of utilizing bacterial DSB repair pathways as targets for the discovery and development of novel antibiotics. Our health systems face a huge challenge in the form of antimicrobial resistance, which may result in many common infections becoming untreatable. The same antibiotics that gave modern medicine its power are fast losing their hold on the germs that cause disease. Many options are being developed to restore the control that antibiotics have on the microbes that cause many diseases. In this perspective, we outline a concept that is built around the way and manner in which bacteria mend their DNA whenever there is a break in the DNA chain. We discuss the merits of finding a new class of drugs that obstruct bacterial ability to mend their broken DNA. In this scenario, a combination of these new drugs with existing drugs or other new drugs that cause breaks in bacterial DNA would become a powerful therapeutic regimen. This concept, when fully developed, will offer hope in our effort to combat antimicrobial-resistant infections.
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16
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Chrabaszcz É, Laureti L, Pagès V. DNA lesions proximity modulates damage tolerance pathways in Escherichia coli. Nucleic Acids Res 2019. [PMID: 29529312 PMCID: PMC5934622 DOI: 10.1093/nar/gky135] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The genome of all organisms is constantly threatened by numerous agents that cause DNA damage. When the replication fork encounters an unrepaired DNA lesion, two DNA damage tolerance pathways are possible: error-prone translesion synthesis (TLS) that requires specialized DNA polymerases, and error-free damage avoidance that relies on homologous recombination (HR). The balance between these two mechanisms is essential since it defines the level of mutagenesis during lesion bypass, allowing genetic variability and adaptation to the environment, but also introduces the risk of generating genome instability. Here we report that the mere proximity of replication-blocking lesions that arise in Escherichia coli's genome during a genotoxic stress leads to a strong increase in the use of the error-prone TLS. We show that this increase is caused by the local inhibition of HR due to the overlapping of single-stranded DNA regions generated downstream of the lesions. This increase in TLS is independent of SOS activation, but its mutagenic effect is additive with the one of SOS. Hence, the combination of SOS induction and lesions proximity leads to a strong increase in TLS that becomes the main lesion tolerance pathway used by the cell during a genotoxic stress.
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Affiliation(s)
- Élodie Chrabaszcz
- Team DNA Damage and Genome Instability, Cancer Research Center of Marseille, CRCM, Aix Marseille univ, CNRS, Inserm, Institut Paoli-Calmettes, 13009 Marseille, France
| | - Luisa Laureti
- Team DNA Damage and Genome Instability, Cancer Research Center of Marseille, CRCM, Aix Marseille univ, CNRS, Inserm, Institut Paoli-Calmettes, 13009 Marseille, France.,Inovarion, F- 75013 Paris, France
| | - Vincent Pagès
- Team DNA Damage and Genome Instability, Cancer Research Center of Marseille, CRCM, Aix Marseille univ, CNRS, Inserm, Institut Paoli-Calmettes, 13009 Marseille, France
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17
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Nagata M, Ishino S, Yamagami T, Ishino Y. Replication protein A complex in Thermococcus kodakarensis interacts with DNA polymerases and helps their effective strand synthesis. Biosci Biotechnol Biochem 2019; 83:695-704. [DOI: 10.1080/09168451.2018.1559722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
ABSTRACT
Replication protein A (RPA) is an essential component of DNA metabolic processes. RPA binds to single-stranded DNA (ssDNA) and interacts with multiple DNA-binding proteins. In this study, we showed that two DNA polymerases, PolB and PolD, from the hyperthermophilic archaeon Thermococcus kodakarensis interact directly with RPA in vitro. RPA was expected to play a role in resolving the secondary structure, which may stop the DNA synthesis reaction, in the template ssDNA. Our in vitro DNA synthesis assay showed that the pausing was resolved by RPA for both PolB and PolD. These results supported the fact that RPA interacts with DNA polymerases as a member of the replisome and is involved in the normal progression of DNA replication forks.
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Affiliation(s)
- Mariko Nagata
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
| | - Sonoko Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
| | - Takeshi Yamagami
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
| | - Yoshizumi Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
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18
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Barrett TC, Mok WWK, Murawski AM, Brynildsen MP. Enhanced antibiotic resistance development from fluoroquinolone persisters after a single exposure to antibiotic. Nat Commun 2019; 10:1177. [PMID: 30862812 PMCID: PMC6414640 DOI: 10.1038/s41467-019-09058-4] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 02/12/2019] [Indexed: 12/21/2022] Open
Abstract
Bacterial persisters are able to tolerate high levels of antibiotics and give rise to new populations. Persister tolerance is generally attributed to minimally active cellular processes that prevent antibiotic-induced damage, which has led to the supposition that persister offspring give rise to antibiotic-resistant mutants at comparable rates to normal cells. Using time-lapse microscopy to monitor Escherichia coli populations following ofloxacin treatment, we find that persisters filament extensively and induce impressive SOS responses before returning to a normal appearance. Further, populations derived from fluoroquinolone persisters contain significantly greater quantities of antibiotic-resistant mutants than those from untreated controls. We confirm that resistance is heritable and that the enhancement requires RecA, SOS induction, an opportunity to recover from treatment, and the involvement of error-prone DNA polymerase V (UmuDC). These findings show that fluoroquinolones damage DNA in persisters and that the ensuing SOS response accelerates the development of antibiotic resistance from these survivors. Fluoroquinolone (FQ)-induced DNA damage in persisters could promote antibiotic resistance. Here, using time-lapse microscopy and genetic analyses, the authors show that after a single round of FQ treatment, SOS response in persisters accelerates the development of resistance to unrelated antibiotics.
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Affiliation(s)
- Theresa C Barrett
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA.,Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, 08854, USA
| | - Wendy W K Mok
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA.,Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, 06032-3305, USA
| | - Allison M Murawski
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA.,Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, 08854, USA
| | - Mark P Brynildsen
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA. .,Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA.
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19
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Sivaramakrishnan P, Gordon AJE, Halliday JA, Herman C. How Acts of Infidelity Promote DNA Break Repair: Collision and Collusion Between DNA Repair and Transcription. Bioessays 2018; 40:e1800045. [PMID: 30091472 PMCID: PMC6334755 DOI: 10.1002/bies.201800045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/07/2018] [Indexed: 12/20/2022]
Abstract
Transcription is a fundamental cellular process and the first step in gene regulation. Although RNA polymerase (RNAP) is highly processive, in growing cells the progression of transcription can be hindered by obstacles on the DNA template, such as damaged DNA. The authors recent findings highlight a trade-off between transcription fidelity and DNA break repair. While a lot of work has focused on the interaction between transcription and nucleotide excision repair, less is known about how transcription influences the repair of DNA breaks. The authors suggest that when the cell experiences stress from DNA breaks, the control of RNAP processivity affects the balance between preserving transcription integrity and DNA repair. Here, how the conflict between transcription and DNA double-strand break (DSB) repair threatens the integrity of both RNA and DNA are discussed. In reviewing this field, the authors speculate on cellular paradigms where this equilibrium is well sustained, and instances where the maintenance of transcription fidelity is favored over genome stability.
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Affiliation(s)
- Priya Sivaramakrishnan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Alasdair J E Gordon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jennifer A Halliday
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Christophe Herman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Baylor College of Medicine, Dan L. Duncan Comprehensive Cancer Center, Houston, TX 77030, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, USA
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20
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González-Tortuero E, Rodríguez-Beltrán J, Radek R, Blázquez J, Rodríguez-Rojas A. Clay-induced DNA breaks as a path for genetic diversity, antibiotic resistance, and asbestos carcinogenesis. Sci Rep 2018; 8:8504. [PMID: 29855603 PMCID: PMC5981458 DOI: 10.1038/s41598-018-26958-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/23/2018] [Indexed: 11/09/2022] Open
Abstract
Natural clays and synthetic nanofibres can have a severe impact on human health. After several decades of research, the molecular mechanism of how asbestos induces cancer is not well understood. Different fibres, including asbestos, can penetrate cell membranes and introduce foreign DNA in bacterial and eukaryotic cells. Incubating Escherichia coli under friction forces with sepiolite, a clayey material, or with asbestos, causes double-strand DNA breaks. Antibiotics and clays are used together in animal husbandry, the mutagenic effect of these fibres could be a pathway to antibiotic resistance due to the friction provided by peristalsis of the gut from farm animals in addition to horizontal gene transfer. Moreover, we raise the possibility that the same mechanism could generate bacteria diversity in natural scenarios, playing a role in the evolution of species. Finally, we provide a new model on how asbestos may promote mutagenesis and cancer based on the observed mechanical genotoxicity.
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Affiliation(s)
- Enrique González-Tortuero
- Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301, 12587, Berlin, Germany.,Berlin Centre for Genomics in Biodiversity Research (BeGenDiv), Königin-Luise-Straße 6-8, 14195, Berlin, Germany.,Institute for Genome Sciences, University of Maryland Baltimore School of Medicine, 670 West Baltimore Street, 21201, Baltimore, MD, USA
| | - Jerónimo Rodríguez-Beltrán
- Department of Microbial Biotechnology, Spanish National Center for Biotechnology, Calle Darwin 3, 28049, Madrid, Spain
| | - Renate Radek
- Evolutionary Biology, Institut für Biologie, Freie Universität Berlin, Berlin, Germany
| | - Jesús Blázquez
- Department of Microbial Biotechnology, Spanish National Center for Biotechnology, Calle Darwin 3, 28049, Madrid, Spain
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21
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Cooper B, Islam N, Xu Y, Beard HS, Garrett WM, Gu G, Nou X. Quantitative Proteomic Analysis of
Staphylococcus aureus
Treated With Punicalagin, a Natural Antibiotic From Pomegranate That Disrupts Iron Homeostasis and Induces SOS. Proteomics 2018. [DOI: 10.1002/pmic.201700461] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Bret Cooper
- Soybean Genomics and Improvement Laboratory USDA‐ARS Beltsville MD USA
| | - Nazrul Islam
- Department of Food Science and Human Nutrition University of Maryland College Park MD USA
| | - Yunfeng Xu
- College of Food Science and Engineering Northwest A&F University Yangling P. R. China
| | - Hunter S. Beard
- Soybean Genomics and Improvement Laboratory USDA‐ARS Beltsville MD USA
| | - Wesley M. Garrett
- Animal Biosciences and Biotechnology Laboratory USDA‐ARS Beltsville MD USA
| | - Ganyu Gu
- Virginia Tech Eastern Shore Agricultural Research and Extension Centers Painter VA USA
| | - Xiangwu Nou
- Environmental Microbial and Food Safety Laboratory USDA‐ARS Beltsville MD USA
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22
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Ferencziová V, Harami GM, Németh JB, Vellai T, Kovács M. Functional fine-tuning between bacterial DNA recombination initiation and quality control systems. PLoS One 2018; 13:e0192483. [PMID: 29470542 PMCID: PMC5823372 DOI: 10.1371/journal.pone.0192483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 01/24/2018] [Indexed: 11/22/2022] Open
Abstract
Homologous recombination (HR) is crucial for the error-free repair of DNA double-strand breaks (DSBs) and the restart of stalled replication. However, imprecise HR can lead to genome instability, highlighting the importance of HR quality control. After DSB formation, HR proceeds via DNA end resection and recombinase loading, whereas helicase-catalyzed disruption of a subset of subsequently formed DNA invasions is thought to be essential for maintaining HR accuracy via inhibiting illegitimate (non-allelic) recombination. Here we show that in vitro characterized mechanistic aberrations of E. coli RecBCD (resection and recombinase loading) RecQ (multifunctional DNA-restructuring helicase) mutant enzyme variants, on one hand, cumulatively deteriorate cell survival under certain conditions of genomic stress. On the other hand, we find that RecBCD and RecQ defects functionally compensate each other in terms of HR accuracy. The abnormally long resection and unproductive recombinase loading activities of a mutant RecBCD complex (harboring the D1080A substitution in RecB) cause enhanced illegitimate recombination. However, this compromised HR-accuracy phenotype is suppressed in double mutant strains harboring mutant RecQ variants with abnormally enhanced helicase and inefficient invasion disruptase activities. These results frame an in vivo context for the interplay of biochemical activities leading to illegitimate recombination, and underscore its long-range genome instability effects manifest in higher eukaryotes.
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Affiliation(s)
- Veronika Ferencziová
- Department of Biochemistry, ELTE-MTA “Momentum” Motor Enzymology Research Group, Eötvös Loránd University, Pázmány P. s. 1/c, Budapest, Hungary
| | - Gábor M. Harami
- Department of Biochemistry, ELTE-MTA “Momentum” Motor Enzymology Research Group, Eötvös Loránd University, Pázmány P. s. 1/c, Budapest, Hungary
| | - Julianna B. Németh
- Department of Biochemistry, ELTE-MTA “Momentum” Motor Enzymology Research Group, Eötvös Loránd University, Pázmány P. s. 1/c, Budapest, Hungary
| | - Tibor Vellai
- Department of Genetics, Eötvös Loránd University, Pázmány P. s. 1/c, Budapest, Hungary
| | - Mihály Kovács
- Department of Biochemistry, ELTE-MTA “Momentum” Motor Enzymology Research Group, Eötvös Loránd University, Pázmány P. s. 1/c, Budapest, Hungary
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23
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Levipan HA, Quezada J, Avendaño-Herrera R. Stress Tolerance-Related Genetic Traits of Fish Pathogen Flavobacterium psychrophilum in a Mature Biofilm. Front Microbiol 2018; 9:18. [PMID: 29410654 PMCID: PMC5787105 DOI: 10.3389/fmicb.2018.00018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 01/05/2018] [Indexed: 11/25/2022] Open
Abstract
Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease and rainbow trout fry syndrome, and hence this bacterium is placed among the most important salmonid pathogens in the freshwater aquaculture industry. Since bacteria in biofilms differ substantially from free-living counterparts, this study sought to find the main differences in gene expression between sessile and planktonic states of F. psychrophilum LM-02-Fp and NCMB1947T, with focus on stress-related changes in gene expression occurring during biofilm formation. To this end, biofilm and planktonic samples were analyzed by RNA sequencing to detect differentially expressed candidate genes (DECGs) between the two growth states, and decreasing the effects of interstrain variation by considering only genes with log2-fold changes ≤ −2 and ≥ 2 at Padj-values ≤ 0.001 as DECGs. Overall, 349 genes accounting for ~15% of total number of genes expressed in transcriptomes of F. psychrophilum LM-02-Fp and NCMB1947T (n = 2327) were DECGs between biofilm and planktonic states. Approximately 83 and 81% of all up- and down-regulated candidate genes in mature biofilms, respectively, were assigned to at least one gene ontology term; these were primarily associated with the molecular function term “catalytic activity.” We detected a potential stress response in mature biofilms, characterized by a generalized down-regulation of DECGs with roles in the protein synthesis machinery (n = 63, primarily ribosomal proteins) and energy conservation (seven ATP synthase subunit genes), as well as an up-regulation of DECGs involved in DNA repair (ruvC, recO, phrB1, smf, and dnaQ) and oxidative stress response (cytochrome C peroxidase, probable peroxiredoxin, and a probable thioredoxin). These results support the idea of a strategic trade-off between growth-related processes and cell homeostasis to preserve biofilm structure and metabolic functioning. In addition, LDH-based cytotoxicity assays and an intraperitoneal challenge model for rainbow trout fry agreed with the transcriptomic evidence that the ability of F. psychrophilum to form biofilms could contribute to the virulence. Finally, the reported changes in gene expression, as induced by the plankton-to-biofilm transition, represent the first transcriptomic guideline to obtain insights into the F. psychrophilum biofilm lifestyle that could help understand the prevalence of this bacterium in aquaculture settings.
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Affiliation(s)
- Héctor A Levipan
- Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias Biológicas, Universidad Andres Bello, Viña del Mar, Chile.,Interdisciplinary Center for Aquaculture Research, Concepción, Chile.,Centro de Investigación Marina Quintay (CIMARQ), Universidad Andrés Bello, Quintay, Chile
| | - Johan Quezada
- Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias Biológicas, Universidad Andres Bello, Viña del Mar, Chile.,Interdisciplinary Center for Aquaculture Research, Concepción, Chile
| | - Ruben Avendaño-Herrera
- Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias Biológicas, Universidad Andres Bello, Viña del Mar, Chile.,Interdisciplinary Center for Aquaculture Research, Concepción, Chile.,Centro de Investigación Marina Quintay (CIMARQ), Universidad Andrés Bello, Quintay, Chile
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24
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Claussin C, Porubský D, Spierings DCJ, Halsema N, Rentas S, Guryev V, Lansdorp PM, Chang M. Genome-wide mapping of sister chromatid exchange events in single yeast cells using Strand-seq. eLife 2017; 6:e30560. [PMID: 29231811 PMCID: PMC5734873 DOI: 10.7554/elife.30560] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 12/08/2017] [Indexed: 01/09/2023] Open
Abstract
Homologous recombination involving sister chromatids is the most accurate, and thus most frequently used, form of recombination-mediated DNA repair. Despite its importance, sister chromatid recombination is not easily studied because it does not result in a change in DNA sequence, making recombination between sister chromatids difficult to detect. We have previously developed a novel DNA template strand sequencing technique, called Strand-seq, that can be used to map sister chromatid exchange (SCE) events genome-wide in single cells. An increase in the rate of SCE is an indicator of elevated recombination activity and of genome instability, which is a hallmark of cancer. In this study, we have adapted Strand-seq to detect SCE in the yeast Saccharomyces cerevisiae. We provide the first quantifiable evidence that most spontaneous SCE events in wild-type cells are not due to the repair of DNA double-strand breaks.
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Affiliation(s)
- Clémence Claussin
- European Research Institute for the Biology of Ageing, University Medical Center GroningenUniversity of GroningenGroningenNetherlands
| | - David Porubský
- European Research Institute for the Biology of Ageing, University Medical Center GroningenUniversity of GroningenGroningenNetherlands
| | - Diana CJ Spierings
- European Research Institute for the Biology of Ageing, University Medical Center GroningenUniversity of GroningenGroningenNetherlands
| | - Nancy Halsema
- European Research Institute for the Biology of Ageing, University Medical Center GroningenUniversity of GroningenGroningenNetherlands
| | | | - Victor Guryev
- European Research Institute for the Biology of Ageing, University Medical Center GroningenUniversity of GroningenGroningenNetherlands
| | - Peter M Lansdorp
- European Research Institute for the Biology of Ageing, University Medical Center GroningenUniversity of GroningenGroningenNetherlands
- Terry Fox LaboratoryBC Cancer AgencyVancouverCanada
- Department of Medical GeneticsUniversity of British ColumbiaVancouverCanada
| | - Michael Chang
- European Research Institute for the Biology of Ageing, University Medical Center GroningenUniversity of GroningenGroningenNetherlands
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Possible function of the second RecJ-like protein in stalled replication fork repair by interacting with Hef. Sci Rep 2017; 7:16949. [PMID: 29209094 PMCID: PMC5717133 DOI: 10.1038/s41598-017-17306-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 11/20/2017] [Indexed: 01/03/2023] Open
Abstract
RecJ was originally identified in Escherichia coli and plays an important role in the DNA repair and recombination pathways. Thermococcus kodakarensis, a hyperthermophilic archaeon, has two RecJ-like nucleases. These proteins are designated as GAN (GINS-associated nuclease) and HAN (Hef-associated nuclease), based on the protein they interact with. GAN is probably a counterpart of Cdc45 in the eukaryotic CMG replicative helicase complex. HAN is considered mainly to function with Hef for restoration of the stalled replication fork. In this study, we characterized HAN to clarify its functions in Thermococcus cells. HAN showed single-strand specific 3′ to 5′ exonuclease activity, which was stimulated in the presence of Hef. A gene disruption analysis revealed that HAN was non-essential for viability, but the ΔganΔhan double mutant did not grow under optimal conditions at 85 °C. This deficiency was not fully recovered by introducing the mutant han gene, encoding the nuclease-deficient HAN protein, back into the genome. These results suggest that the unstable replicative helicase complex without GAN performs ineffective fork progression, and thus the stalled fork repair system including HAN becomes more important. The nuclease activity of HAN is required for the function of this protein in T. kodakarensis.
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Nagata M, Ishino S, Yamagami T, Ogino H, Simons JR, Kanai T, Atomi H, Ishino Y. The Cdc45/RecJ-like protein forms a complex with GINS and MCM, and is important for DNA replication in Thermococcus kodakarensis. Nucleic Acids Res 2017; 45:10693-10705. [PMID: 28977567 PMCID: PMC5737688 DOI: 10.1093/nar/gkx740] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 08/12/2017] [Indexed: 01/18/2023] Open
Abstract
The archaeal minichromosome maintenance (MCM) has DNA helicase activity, which is stimulated by GINS in several archaea. In the eukaryotic replicative helicase complex, Cdc45 forms a complex with MCM and GINS, named as CMG (Cdc45-MCM-GINS). Cdc45 shares sequence similarity with bacterial RecJ. A Cdc45/RecJ-like protein from Thermococcus kodakarensis shows a bacterial RecJ-like exonuclease activity, which is stimulated by GINS in vitro. Therefore, this archaeal Cdc45/RecJ is designated as GAN, from GINS-associated nuclease. In this study, we identified the CMG-like complex in T. kodakarensis cells. The GAN·GINS complex stimulated the MCM helicase, but MCM did not affect the nuclease activity of GAN in vitro. The gene disruption analysis showed that GAN was non-essential for its viability but the Δgan mutant did not grow at 93°C. Furthermore, the Δgan mutant showed a clear retardation in growth as compared with the parent cells under optimal conditions at 85°C. These deficiencies were recovered by introducing the gan gene encoding the nuclease deficient GAN protein back to the genome. These results suggest that the replicative helicase complex without GAN may become unstable and ineffective in replication fork progression. The nuclease activity of GAN is not related to the growth defects of the Δgan mutant cells.
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Affiliation(s)
- Mariko Nagata
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Fukuoka 812-8581, Japan
| | - Sonoko Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Fukuoka 812-8581, Japan
| | - Takeshi Yamagami
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Fukuoka 812-8581, Japan
| | - Hiromi Ogino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Fukuoka 812-8581, Japan
| | - Jan-Robert Simons
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Kyoto 615-8510, Japan
| | - Tamotsu Kanai
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Kyoto 615-8510, Japan
| | - Haruyuki Atomi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Kyoto 615-8510, Japan
| | - Yoshizumi Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Fukuoka 812-8581, Japan
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27
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Danilowicz C, Hermans L, Coljee V, Prévost C, Prentiss M. ATP hydrolysis provides functions that promote rejection of pairings between different copies of long repeated sequences. Nucleic Acids Res 2017; 45:8448-8462. [PMID: 28854739 PMCID: PMC5737215 DOI: 10.1093/nar/gkx582] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/05/2017] [Indexed: 01/30/2023] Open
Abstract
During DNA recombination and repair, RecA family proteins must promote rapid joining of homologous DNA. Repeated sequences with >100 base pair lengths occupy more than 1% of bacterial genomes; however, commitment to strand exchange was believed to occur after testing ∼20-30 bp. If that were true, pairings between different copies of long repeated sequences would usually become irreversible. Our experiments reveal that in the presence of ATP hydrolysis even 75 bp sequence-matched strand exchange products remain quite reversible. Experiments also indicate that when ATP hydrolysis is present, flanking heterologous dsDNA regions increase the reversibility of sequence matched strand exchange products with lengths up to ∼75 bp. Results of molecular dynamics simulations provide insight into how ATP hydrolysis destabilizes strand exchange products. These results inspired a model that shows how pairings between long repeated sequences could be efficiently rejected even though most homologous pairings form irreversible products.
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Affiliation(s)
| | - Laura Hermans
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Vincent Coljee
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Chantal Prévost
- Laboratoire de Biochimie Théorique, CNRS UMR 9080, IBPC, Paris, France
| | - Mara Prentiss
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
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Raguse M, Torres R, Seco EM, Gándara C, Ayora S, Moeller R, Alonso JC. Bacillus subtilis DisA helps to circumvent replicative stress during spore revival. DNA Repair (Amst) 2017; 59:57-68. [PMID: 28961460 DOI: 10.1016/j.dnarep.2017.09.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/24/2017] [Accepted: 09/08/2017] [Indexed: 02/06/2023]
Abstract
The mechanisms that allow to circumvent replicative stress, and to resume DNA synthesis are poorly understood in Bacillus subtilis. To study the role of the diadenylate cyclase DisA and branch migration translocase (BMT) RadA/Sms in restarting a stalled replication fork, we nicked and broke the circular chromosome of an inert mature haploid spore, damaged the bases, and measured survival of reviving spores. During undisturbed ripening, nicks and breaks should be repaired by pathways that do not invoke long-range end resection or genetic exchange by homologous recombination, after which DNA replication might be initiated. We found that DNA damage reduced the viability of spores that lacked DisA, BMT (RadA/Sms, RuvAB or RecG), the Holliday junction resolvase RecU, or the translesion synthesis DNA polymerases (PolY1 or PolY2). DisA and RadA/Sms, in concert with RuvAB, RecG, RecU, PolY1 or PolY2, are needed to bypass replication-blocking lesions. DisA, which binds to stalled or reversed forks, did not apparently affect initiation of PriA-dependent DNA replication in vitro. We propose that DisA is necessary to coordinate responses to replicative stress; it could help to circumvent damaged template bases that otherwise impede fork progression.
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Affiliation(s)
- Marina Raguse
- German Aerospace Center (DLReV), Institute of Aerospace Medicine, Radiation Biology Department, Space Microbiology Research Group, Linder Hoehe, D-51147 Cologne (Köln), Germany
| | - Rubén Torres
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Elena M Seco
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Carolina Gándara
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Silvia Ayora
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Ralf Moeller
- German Aerospace Center (DLReV), Institute of Aerospace Medicine, Radiation Biology Department, Space Microbiology Research Group, Linder Hoehe, D-51147 Cologne (Köln), Germany.
| | - Juan C Alonso
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Cantoblanco, 28049 Madrid, Spain.
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29
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Đermić E, Zahradka D, Vujaklija D, Ivanković S, Đermić D. 3'-Terminated Overhangs Regulate DNA Double-Strand Break Processing in Escherichia coli. G3 (BETHESDA, MD.) 2017; 7:3091-3102. [PMID: 28710290 PMCID: PMC5592934 DOI: 10.1534/g3.117.043521] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 07/11/2017] [Indexed: 01/18/2023]
Abstract
Double-strand breaks (DSBs) are lethal DNA lesions, which are repaired by homologous recombination in Escherichia coli To study DSB processing in vivo, we induced DSBs into the E. coli chromosome by γ-irradiation and measured chromosomal degradation. We show that the DNA degradation is regulated by RecA protein concentration and its rate of association with single-stranded DNA (ssDNA). RecA decreased DNA degradation in wild-type, recB, and recD strains, indicating that it is a general phenomenon in E. coli On the other hand, DNA degradation was greatly reduced and unaffected by RecA in the recB1080 mutant (which produces long overhangs) and in a strain devoid of four exonucleases that degrade a 3' tail (ssExos). 3'-5' ssExos deficiency is epistatic to RecA deficiency concerning DNA degradation, suggesting that bound RecA is shielding the 3' tail from degradation by 3'-5' ssExos. Since 3' tail preservation is common to all these situations, we infer that RecA polymerization constitutes a subset of mechanisms for preserving the integrity of 3' tails emanating from DSBs, along with 3' tail's massive length, or prevention of their degradation by inactivation of 3'-5' ssExos. Thus, we conclude that 3' overhangs are crucial in controlling the extent of DSB processing in E. coli This study suggests a regulatory mechanism for DSB processing in E. coli, wherein 3' tails impose a negative feedback loop on DSB processing reactions, specifically on helicase reloading onto dsDNA ends.
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Affiliation(s)
- Edyta Đermić
- Department of Plant Pathology, Faculty of Agriculture, University of Zagreb, 10000, Croatia
| | - Davor Zahradka
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
| | - Dušica Vujaklija
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
| | - Siniša Ivanković
- Division of Molecular Medicine, Ruđer Bošković Institute, 10000 Zagreb, Croatia
| | - Damir Đermić
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
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30
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Abstract
Replication forks frequently are challenged by lesions on the DNA template, replication-impeding DNA secondary structures, tightly bound proteins or nucleotide pool imbalance. Studies in bacteria have suggested that under these circumstances the fork may leave behind single-strand DNA gaps that are subsequently filled by homologous recombination, translesion DNA synthesis or template-switching repair synthesis. This review focuses on the template-switching pathways and how the mechanisms of these processes have been deduced from biochemical and genetic studies. I discuss how template-switching can contribute significantly to genetic instability, including mutational hotspots and frequent genetic rearrangements, and how template-switching may be elicited by replication fork damage.
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Affiliation(s)
- Susan T Lovett
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA, 2454-9110, USA.
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31
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Ivanković S, Vujaklija D, Đermić D. Nucleolytic degradation of 3'-ending overhangs is essential for DNA-end resection in RecA-loading deficient recB mutants of Escherichia coli. DNA Repair (Amst) 2017; 57:56-65. [PMID: 28689072 DOI: 10.1016/j.dnarep.2017.06.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 01/06/2023]
Abstract
Degradation of a 5'-ending strand is the hallmark of the universal process of DNA double strand break (DSB) resection, which results in creation of the central recombination intermediate, a 3'-ending overhang. Here we show that in Escherichia coli recB1080/recB1067 mutants, which are devoid of RecBCD's nuclease and RecA loading activities, degradation of the unwound 3' tail is as essential as is degradation of its 5'-ending complement. Namely, a synergistic action of ExoI, ExoVII, SbcCD and ExoX single-strand specific exonucleases (ssExos) of 3'-5' polarity was essential for preserving cell viability, DNA repair and homologous recombination in the recB1080/recB1067 mutants, to the same extent as the redundant action of 5'-tail trimming ssExos RecJ and ExoVII. recB1080 derivatives lacking 3'-5' ssExos also showed a strong induction of the SOS response and greatly increased SOS-dependent mutagenesis. Furthermore, we show that ExoI and ExoVII ssExos act synergistically in suppressing illegitimate recombination in the recB1080 mutant but not in a wt strain, while working in concert with the RecQ helicase. Remarkably, 3'-5' ssExos show synergism with RecQ helicase in the recB1080 mutant in all the assays tested. The effect of inactivation of 3'-5' ssExos in the recB1080/recB1067 mutants was much stronger than in wt, recD, and recB strains. These results demonstrate that the presence of a long, reactive 3' overhang can be as toxic for a cell as its complete absence, i.e. it may prevent DSB repair. Our results indicate that coupling of helicase and RecA-loading activity during dsDNA-end resection is crucial in avoiding the deleterious effects of a long and stabile 3' tail in E. coli.
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Affiliation(s)
- Siniša Ivanković
- Ruđer Bošković Institute, Division of Molecular Medicine, Zagreb, Croatia
| | - Dušica Vujaklija
- Ruđer Bošković Institute, Division of Molecular Biology, Zagreb, Croatia
| | - Damir Đermić
- Ruđer Bošković Institute, Division of Molecular Biology, Zagreb, Croatia.
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32
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Torres R, Romero H, Rodríguez-Cerrato V, Alonso JC. Interplay between Bacillus subtilis RecD2 and the RecG or RuvAB helicase in recombinational repair. DNA Repair (Amst) 2017; 55:40-46. [DOI: 10.1016/j.dnarep.2017.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 05/08/2017] [Accepted: 05/10/2017] [Indexed: 10/24/2022]
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Lee JY, Steinfeld JB, Qi Z, Kwon Y, Sung P, Greene EC. Sequence imperfections and base triplet recognition by the Rad51/RecA family of recombinases. J Biol Chem 2017; 292:11125-11135. [PMID: 28476890 DOI: 10.1074/jbc.m117.787614] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/27/2017] [Indexed: 11/06/2022] Open
Abstract
Homologous recombination plays key roles in double-strand break repair, rescue, and repair of stalled replication forks and meiosis. The broadly conserved Rad51/RecA family of recombinases catalyzes the DNA strand invasion reaction that takes place during homologous recombination. We have established single-stranded (ss)DNA curtain assays for measuring individual base triplet steps during the early stages of strand invasion. Here, we examined how base triplet stepping by RecA, Rad51, and Dmc1 is affected by DNA sequence imperfections, such as single and multiple mismatches, abasic sites, and single nucleotide insertions. Our work reveals features of base triplet stepping that are conserved among these three phylogenetic lineages of the Rad51/RecA family and also reveals lineage-specific behaviors reflecting properties that are unique to each recombinase. These findings suggest that Dmc1 is tolerant of single mismatches, multiple mismatches, and even abasic sites, whereas RecA and Rad51 are not. Interestingly, the presence of single nucleotide insertion abolishes recognition of an adjacent base triplet by all three recombinases. On the basis of these findings, we describe models for how sequence imperfections may affect base triplet recognition by Rad51/RecA family members, and we discuss how these models and our results may relate to the different biological roles of RecA, Rad51, and Dmc1.
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Affiliation(s)
- Ja Yil Lee
- From the Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032 and
| | - Justin B Steinfeld
- From the Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032 and
| | - Zhi Qi
- From the Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032 and
| | - YoungHo Kwon
- the Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06510
| | - Patrick Sung
- the Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06510
| | - Eric C Greene
- From the Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032 and
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Activity and in vivo dynamics of Bacillus subtilis DisA are affected by RadA/Sms and by Holliday junction-processing proteins. DNA Repair (Amst) 2017; 55:17-30. [PMID: 28511132 DOI: 10.1016/j.dnarep.2017.05.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 05/03/2017] [Accepted: 05/04/2017] [Indexed: 12/18/2022]
Abstract
Bacillus subtilis c-di-AMP synthase DisA and RecA-related RadA/Sms are involved in the repair of DNA damage in exponentially growing cells. We provide genetic evidence that DisA or RadA/Sms is epistatic to the branch migration translocase (BMT) RecG and the Holliday junction (HJ) resolvase RecU in response to DNA damage. We provide genetic evidence damage. Functional DisA-YFP formed dynamic foci in exponentially growing cells, which moved through the nucleoids at a speed compatible with a DNA-scanning mode. DisA formed more static structures in the absence of RecU or RecG than in wild type cells, while dynamic foci were still observed in cells lacking the BMT RuvAB. Purified DisA synthesizes c-di-AMP, but interaction with RadA/Sms or with HJ DNA decreases DisA-mediated c-di-AMP synthesis. RadA/Sms-YFP also formed dynamic foci in growing cells, but the foci moved throughout the cells rather than just on the nucleoids, and co-localized rarely with DisA-YFP foci, suggesting that RadA/Sms and DisA interact only transiently in unperturbed conditions. Our data suggest a model in which DisA moving along dsDNA indicates absence of DNA damage/replication stress via normal c-di-AMP levels, while interaction with HJ DNA/halted forks leads to reduced c-di-AMP levels and an ensuing block in cell proliferation. RadA/Sms may be involved in modulating DisA activities.
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Dupuy P, Gourion B, Sauviac L, Bruand C. DNA double-strand break repair is involved in desiccation resistance of Sinorhizobium meliloti, but is not essential for its symbiotic interaction with Medicago truncatula. MICROBIOLOGY-SGM 2017; 163:333-342. [PMID: 27902438 DOI: 10.1099/mic.0.000400] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The soil bacterium Sinorhizobium meliloti, a nitrogen-fixing symbiont of legume plants, is exposed to numerous stress conditions in nature, some of which cause the formation of harmful DNA double-strand breaks (DSBs). In particular, the reactive oxygen species (ROS) and the reactive nitrogen species (RNS) produced during symbiosis, and the desiccation occurring in dry soils, are conditions which induce DSBs. Two major systems of DSB repair are known in S. meliloti: homologous recombination (HR) and non-homologous end-joining (NHEJ). However, their role in the resistance to ROS, RNS and desiccation has never been examined in this bacterial species, and the importance of DSB repair in the symbiotic interaction has not been properly evaluated. Here, we constructed S. meliloti strains deficient in HR (by deleting the recA gene) or in NHEJ (by deleting the four ku genes) or both. Interestingly, we observed that ku and/or recA genes are involved in S. meliloti resistance to ROS and RNS. Nevertheless, an S. meliloti strain deficient in both HR and NHEJ was not altered in its ability to establish and maintain an efficient nitrogen-fixing symbiosis with Medicago truncatula, showing that rhizobial DSB repair is not essential for this process. This result suggests either that DSB formation in S. meliloti is efficiently prevented during symbiosis or that DSBs are not detrimental for symbiosis efficiency. In contrast, we found for the first time that both recA and ku genes are involved in S. meliloti resistance to desiccation, suggesting that DSB repair could be important for rhizobium persistence in the soil.
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Affiliation(s)
- Pierre Dupuy
- Laboratoire des Interactions Plantes-Microorganismes, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Benjamin Gourion
- Laboratoire des Interactions Plantes-Microorganismes, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Laurent Sauviac
- Laboratoire des Interactions Plantes-Microorganismes, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Claude Bruand
- Laboratoire des Interactions Plantes-Microorganismes, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
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36
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Ogino H, Ishino S, Kohda D, Ishino Y. The RecJ2 protein in the thermophilic archaeon Thermoplasma acidophilum is a 3'-5' exonuclease that associates with a DNA replication complex. J Biol Chem 2017; 292:7921-7931. [PMID: 28302716 DOI: 10.1074/jbc.m116.767921] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 03/15/2017] [Indexed: 11/06/2022] Open
Abstract
RecJ/cell division cycle 45 (Cdc45) proteins are widely conserved in the three domains of life, i.e. in bacteria, Eukarya, and Archaea. Bacterial RecJ is a 5'-3' exonuclease and functions in DNA repair pathways by using its 5'-3' exonuclease activity. Eukaryotic Cdc45 has no identified enzymatic activity but participates in the CMG complex, so named because it is composed of Cdc45, minichromosome maintenance protein complex (MCM) proteins 2-7, and GINS complex proteins (Sld5, Psf11-3). Eukaryotic Cdc45 and bacterial/archaeal RecJ share similar amino acid sequences and are considered functional counterparts. In Archaea, a RecJ homolog in Thermococcus kodakarensis was shown to associate with GINS and accelerate its nuclease activity and was, therefore, designated GAN (GINS-associated nuclease); however, to date, no archaeal RecJ·MCM·GINS complex has been isolated. The thermophilic archaeon Thermoplasma acidophilum has two RecJ-like proteins, designated TaRecJ1 and TaRecJ2. TaRecJ1 exhibited DNA-specific 5'-3' exonuclease activity, whereas TaRecJ2 had 3'-5' exonuclease activity and preferred RNA over DNA. TaRecJ2, but not TaRecJ1, formed a stable complex with TaGINS in a 2:1 molar ratio. Furthermore, the TaRecJ2·TaGINS complex stimulated activity of TaMCM (T. acidophilum MCM) helicase in vitro, and the TaRecJ2·TaMCM·TaGINS complex was also observed in vivo However, TaRecJ2 did not interact with TaMCM directly and was not required for the helicase activation in vitro These findings suggest that the function of archaeal RecJ in DNA replication evolved divergently from Cdc45 despite conservation of the CMG-like complex formation between Archaea and Eukarya.
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Affiliation(s)
- Hiromi Ogino
- From the Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashiku, Fukuoka 812-8581, Japan and
| | - Sonoko Ishino
- From the Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashiku, Fukuoka 812-8581, Japan and
| | - Daisuke Kohda
- the Medical Institute of Bioregulation, Kyushu University, 3-1-1, Maidashi, Higashiku, Fukuoka 812-8582, Japan
| | - Yoshizumi Ishino
- From the Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashiku, Fukuoka 812-8581, Japan and .,the Medical Institute of Bioregulation, Kyushu University, 3-1-1, Maidashi, Higashiku, Fukuoka 812-8582, Japan
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Motohashi K. Seamless Ligation Cloning Extract (SLiCE) Method Using Cell Lysates from Laboratory Escherichia coli Strains and its Application to SLiP Site-Directed Mutagenesis. Methods Mol Biol 2017; 1498:349-357. [PMID: 27709587 DOI: 10.1007/978-1-4939-6472-7_23] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Cell lysates from laboratory Escherichia coli strains endogenously exhibit homologous recombination activity, which can be utilized for seamless DNA cloning in vitro. This method, termed Seamless Ligation Cloning Extract (SLiCE) cloning, enables high cloning efficiency with simultaneous integration of two unpurified DNA fragments into a vector. In addition, the SLiCE method is highly cost-effective, as several laboratory E. coli strains may be utilized as sources of SLiCE. Previously, the SLiCE technique has been applied to site-directed mutagenesis to develop a novel technique termed SLiCE-mediated polymerase chain reaction (PCR)-based site-directed mutagenesis (SLiP site-directed mutagenesis). Two DNA fragments containing a mutation site can be simultaneously integrated into a vector while avoiding the introduction of undesirable mutations in the vector. Therefore, SLiP site-directed mutagenesis simplifies multiple procedures involved in PCR-based site-directed mutagenesis such as overlap extension method PCR or the Megaprimer method.
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Affiliation(s)
- Ken Motohashi
- Department of Bioresource and Environmental Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-ku, Kyoto, 603-8555, Japan.
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Schlegel S, Genevaux P, de Gier JW. Isolating Escherichia coli strains for recombinant protein production. Cell Mol Life Sci 2016; 74:891-908. [PMID: 27730255 PMCID: PMC5306230 DOI: 10.1007/s00018-016-2371-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 08/22/2016] [Accepted: 09/16/2016] [Indexed: 12/14/2022]
Abstract
Escherichia coli has been widely used for the production of recombinant proteins. To improve protein production yields in E. coli, directed engineering approaches have been commonly used. However, there are only few reported examples of the isolation of E. coli protein production strains using evolutionary approaches. Here, we first give an introduction to bacterial evolution and mutagenesis to set the stage for discussing how so far selection- and screening-based approaches have been used to isolate E. coli protein production strains. Finally, we discuss how evolutionary approaches may be used in the future to isolate E. coli strains with improved protein production characteristics.
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Affiliation(s)
- Susan Schlegel
- Department of Environmental Systems Science, ETH Zürich, 8092, Zürich, Switzerland
| | - Pierre Genevaux
- Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Jan-Willem de Gier
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrheniusväg 16C, 106 91, Stockholm, Sweden.
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Pinto C, Kasaciunaite K, Seidel R, Cejka P. Human DNA2 possesses a cryptic DNA unwinding activity that functionally integrates with BLM or WRN helicases. eLife 2016; 5. [PMID: 27612385 PMCID: PMC5030094 DOI: 10.7554/elife.18574] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 09/08/2016] [Indexed: 12/13/2022] Open
Abstract
Human DNA2 (hDNA2) contains both a helicase and a nuclease domain within the same polypeptide. The nuclease of hDNA2 is involved in a variety of DNA metabolic processes. Little is known about the role of the hDNA2 helicase. Using bulk and single-molecule approaches, we show that hDNA2 is a processive helicase capable of unwinding kilobases of dsDNA in length. The nuclease activity prevents the engagement of the helicase by competing for the same substrate, hence prominent DNA unwinding by hDNA2 alone can only be observed using the nuclease-deficient variant. We show that the helicase of hDNA2 functionally integrates with BLM or WRN helicases to promote dsDNA degradation by forming a heterodimeric molecular machine. This collectively suggests that the hDNA2 motor promotes the enzyme's capacity to degrade dsDNA in conjunction with BLM or WRN and thus promote the repair of broken DNA. DOI:http://dx.doi.org/10.7554/eLife.18574.001
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Affiliation(s)
- Cosimo Pinto
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | | | - Ralf Seidel
- Institute of Experimental Physics I, University of Leipzig, Leipzig, Germany
| | - Petr Cejka
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
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Remodeling and Control of Homologous Recombination by DNA Helicases and Translocases that Target Recombinases and Synapsis. Genes (Basel) 2016; 7:genes7080052. [PMID: 27548227 PMCID: PMC4999840 DOI: 10.3390/genes7080052] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/24/2016] [Accepted: 08/12/2016] [Indexed: 11/16/2022] Open
Abstract
Recombinase enzymes catalyse invasion of single-stranded DNA (ssDNA) into homologous duplex DNA forming "Displacement loops" (D-loops), a process called synapsis. This triggers homologous recombination (HR), which can follow several possible paths to underpin DNA repair and restart of blocked and collapsed DNA replication forks. Therefore, synapsis can be a checkpoint for controlling whether or not, how far, and by which pathway, HR proceeds to overcome an obstacle or break in a replication fork. Synapsis can be antagonized by limiting access of a recombinase to ssDNA and by dissociation of D-loops or heteroduplex formed by synapsis. Antagonists include DNA helicases and translocases that are identifiable in eukaryotes, bacteria and archaea, and which target synaptic and pre-synaptic DNA structures thereby controlling HR at early stages. Here we survey these events with emphasis on enabling DNA replication to be resumed from sites of blockage or collapse. We also note how knowledge of anti-recombination activities could be useful to improve efficiency of CRISPR-based genome editing.
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Cooper DL, Lovett ST. Recombinational branch migration by the RadA/Sms paralog of RecA in Escherichia coli. eLife 2016; 5. [PMID: 26845522 PMCID: PMC4786428 DOI: 10.7554/elife.10807] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 02/03/2016] [Indexed: 12/31/2022] Open
Abstract
RadA (also known as 'Sms') is a highly conserved protein, found in almost all eubacteria and plants, with sequence similarity to the RecA strand exchange protein and a role in homologous recombination. We investigate here the biochemical properties of the E. coli RadA protein and several mutant forms. RadA is a DNA-dependent ATPase, a DNA-binding protein and can stimulate the branch migration phase of RecA-mediated strand transfer reactions. RadA cannot mediate synaptic pairing between homologous DNA molecules but can drive branch migration to extend the region of heteroduplex DNA, even without RecA. Unlike other branch migration factors RecG and RuvAB, RadA stimulates branch migration within the context of the RecA filament, in the direction of RecA-mediated strand exchange. We propose that RadA-mediated branch migration aids recombination by allowing the 3’ invading strand to be incorporated into heteroduplex DNA and to be extended by DNA polymerases. DOI:http://dx.doi.org/10.7554/eLife.10807.001 Damage to the DNA of a cell can cause serious harm, and so cells have several ways in which they can repair DNA. Most of these processes rely on the fact that each of the two strands that make up a DNA molecule can be used as a template to build the other strand. However, this is not possible if both strands of the DNA break in the same place. This form of damage can be repaired in a process called homologous recombination, which uses an identical copy of the broken DNA molecule to repair the broken strands. As a result, this process can only occur during cell division shortly after a cell has duplicated its DNA. One important step of homologous recombination is called strand exchange. This involves one of the broken strands swapping places with part of the equivalent strand in the intact DNA molecule. To do so, the strands of the intact DNA molecule separate in the region that will be used for the repair, and the broken strand can then use the other non-broken DNA strand as a template to replace any missing sections of DNA. The region of the intact DNA molecule where the strands need to separate often grows during this process: this is known as branch migration. In bacteria, a protein called RecA plays a fundamental role in controlling strand exchange, but there are other, similar proteins whose roles in homologous recombination are less well known. Cooper and Lovett have now purified one of these proteins, called RadA, from the Escherichia coli species of bacteriato study how it affects homologous recombination. This revealed that RadA can bind to single-stranded DNA and stimulate branch migration to increase the rate of homologous recombination. Further investigation revealed that RadA allows branch migration to occur even when RecA is missing, but that RadA is unable to begin strand exchange if RecA is not present. The process of branch migration stabilizes the DNA molecules during homologous recombination and may also allow the repaired DNA strand to engage the machinery that copies DNA. Cooper and Lovett also used genetic techniques to alter the structure of specific regions of RadA and found out which parts of the protein affect the ability of RadA to stimulate branch migration. Future challenges are to find out what effect RadA has on the structure of RecA and how RadA promotes branch migration. DOI:http://dx.doi.org/10.7554/eLife.10807.002
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Affiliation(s)
- Deani L Cooper
- Department of Biology, Brandeis University, Waltham, United States.,Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, United States
| | - Susan T Lovett
- Department of Biology, Brandeis University, Waltham, United States.,Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, United States
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Brown LT, Sutera VA, Zhou S, Weitzel CS, Cheng Y, Lovett ST. Connecting Replication and Repair: YoaA, a Helicase-Related Protein, Promotes Azidothymidine Tolerance through Association with Chi, an Accessory Clamp Loader Protein. PLoS Genet 2015; 11:e1005651. [PMID: 26544712 PMCID: PMC4636137 DOI: 10.1371/journal.pgen.1005651] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 10/14/2015] [Indexed: 11/23/2022] Open
Abstract
Elongating DNA polymerases frequently encounter lesions or structures that impede progress and require repair before DNA replication can be completed. Therefore, directing repair factors to a blocked fork, without interfering with normal replication, is important for proper cell function, and it is a process that is not well understood. To study this process, we have employed the chain-terminating nucleoside analog, 3’ azidothymidine (AZT) and the E. coli genetic system, for which replication and repair factors have been well-defined. By using high-expression suppressor screens, we identified yoaA, encoding a putative helicase, and holC, encoding the Chi component of the replication clamp loader, as genes that promoted tolerance to AZT. YoaA is a putative Fe-S helicase in the XPD/RAD3 family for which orthologs can be found in most bacterial genomes; E. coli has a paralog to YoaA, DinG, which possesses 5’ to 3’ helicase activity and an Fe-S cluster essential to its activity. Mutants in yoaA are sensitive to AZT exposure; dinG mutations cause mild sensitivity to AZT and exacerbate the sensitivity of yoaA mutant strains. Suppression of AZT sensitivity by holC or yoaA was mutually codependent and we provide evidence here that YoaA and Chi physically interact. Interactions of Chi with single-strand DNA binding protein (SSB) and with Psi were required to aid AZT tolerance, as was the proofreading 3’ exonuclease, DnaQ. Our studies suggest that repair is coupled to blocked replication through these interactions. We hypothesize that SSB, through Chi, recruits the YoaA helicase to replication gaps and that unwinding of the nascent strand promotes repair and AZT excision. This recruitment prevents the toxicity of helicase activity and aids the handoff of repair with replication factors, ensuring timely repair and resumption of replication. During the replication of the cell’s genetic material, difficulties are often encountered. These problems require the recruitment of special proteins to repair DNA so that replication can be completed. The failure to do so causes cell death or deleterious changes to the cell’s genetic material. In humans, these genetic changes can promote cancer formation. Our study identifies a repair protein that is recruited to problem sites by interactions with the replication machinery. These interactions provide a means by which the cell can sense, respond to and repair damage that interferes with the completion of DNA replication.
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Affiliation(s)
- Laura T. Brown
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center MS029, Brandeis University, Waltham, Massachusetts, United States of America
| | - Vincent A. Sutera
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center MS029, Brandeis University, Waltham, Massachusetts, United States of America
| | - Shen Zhou
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center MS029, Brandeis University, Waltham, Massachusetts, United States of America
| | - Christopher S. Weitzel
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center MS029, Brandeis University, Waltham, Massachusetts, United States of America
| | - Yisha Cheng
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center MS029, Brandeis University, Waltham, Massachusetts, United States of America
| | - Susan T. Lovett
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center MS029, Brandeis University, Waltham, Massachusetts, United States of America
- * E-mail:
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Abstract
DNA exonucleases, enzymes that hydrolyze phosphodiester bonds in DNA from a free end, play important cellular roles in DNA repair, genetic recombination and mutation avoidance in all organisms. This article reviews the structure, biochemistry, and biological functions of the 17 exonucleases currently identified in the bacterium Escherichia coli. These include the exonucleases associated with DNA polymerases I (polA), II (polB), and III (dnaQ/mutD); Exonucleases I (xonA/sbcB), III (xthA), IV, VII (xseAB), IX (xni/xgdG), and X (exoX); the RecBCD, RecJ, and RecE exonucleases; SbcCD endo/exonucleases; the DNA exonuclease activities of RNase T (rnt) and Endonuclease IV (nfo); and TatD. These enzymes are diverse in terms of substrate specificity and biochemical properties and have specialized biological roles. Most of these enzymes fall into structural families with characteristic sequence motifs, and members of many of these families can be found in all domains of life.
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Okegawa Y, Motohashi K. A simple and ultra-low cost homemade seamless ligation cloning extract (SLiCE) as an alternative to a commercially available seamless DNA cloning kit. Biochem Biophys Rep 2015; 4:148-151. [PMID: 29124198 PMCID: PMC5668909 DOI: 10.1016/j.bbrep.2015.09.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 09/08/2015] [Accepted: 09/09/2015] [Indexed: 11/27/2022] Open
Abstract
The seamless ligation cloning extract (SLiCE) method is a novel seamless DNA cloning tool that utilizes homologous recombination activities in Escherichia coli cell lysates to assemble DNA fragments into a vector. Several laboratory E. coli strains can be used as a source for the SLiCE extract; therefore, the SLiCE-method is highly cost-effective.The SLiCE has sufficient cloning ability to support conventional DNA cloning, and can simultaneously incorporate two unpurified DNA fragments into vector. Recently, many seamless DNA cloning kits have become commercially available; these are generally very convenient, but expensive. In this study, we evaluated the cloning efficiencies between a simple and highly cost-effective SLiCE-method and a commercial kit under various molar ratios of insert DNA fragments to vector DNA. This assessment identified that the SLiCE from a laboratory E. coli strain yielded 30−85% of the colony formation rate of a commercially available seamless DNA cloning kit. The cloning efficiencies of both methods were highly effective, exhibiting over 80% success rate under all conditions examined. These results suggest that SLiCE from a laboratory E. coli strain can efficiently function as an effective alternative to commercially available seamless DNA cloning kits.
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Affiliation(s)
- Yuki Okegawa
- Department of Bioresource and Environmental Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-ku, Kyoto 603-8555, Japan
| | - Ken Motohashi
- Department of Bioresource and Environmental Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-ku, Kyoto 603-8555, Japan
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Cejka P. DNA End Resection: Nucleases Team Up with the Right Partners to Initiate Homologous Recombination. J Biol Chem 2015; 290:22931-8. [PMID: 26231213 DOI: 10.1074/jbc.r115.675942] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The repair of DNA double-strand breaks by homologous recombination commences by nucleolytic degradation of the 5'-terminated strand of the DNA break. This leads to the formation of 3'-tailed DNA, which serves as a substrate for the strand exchange protein Rad51. The nucleoprotein filament then invades homologous DNA to drive template-directed repair. In this review, I discuss mainly the mechanisms of DNA end resection in Saccharomyces cerevisiae, which includes short-range resection by Mre11-Rad50-Xrs2 and Sae2, as well as processive long-range resection by Sgs1-Dna2 or Exo1 pathways. Resection mechanisms are highly conserved between yeast and humans, and analogous machineries are found in prokaryotes as well.
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Affiliation(s)
- Petr Cejka
- From the Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
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46
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Evaluation of seamless ligation cloning extract preparation methods from an Escherichia coli laboratory strain. Anal Biochem 2015; 486:51-3. [PMID: 26133399 DOI: 10.1016/j.ab.2015.06.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 06/23/2015] [Accepted: 06/24/2015] [Indexed: 11/22/2022]
Abstract
Seamless ligation cloning extract (SLiCE) is a simple and efficient method for DNA cloning without the use of restriction enzymes. Instead, SLiCE uses homologous recombination activities from Escherichia coli cell lysates. To date, SLiCE preparation has been performed using an expensive commercially available lytic reagent. To expand the utility of the SLiCE method, we evaluated different methods for SLiCE preparation that avoid using this reagent. Consequently, cell extracts prepared with buffers containing Triton X-100, which is a common and low-cost nonionic detergent, exhibited sufficient cloning activity for seamless gene incorporation into a vector.
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47
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Kupczok A, Landan G, Dagan T. The Contribution of Genetic Recombination to CRISPR Array Evolution. Genome Biol Evol 2015; 7:1925-39. [PMID: 26085541 PMCID: PMC4524480 DOI: 10.1093/gbe/evv113] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2015] [Indexed: 12/19/2022] Open
Abstract
CRISPR (clustered regularly interspaced short palindromic repeats) is a microbial immune system against foreign DNA. Recognition sequences (spacers) encoded within the CRISPR array mediate the immune reaction in a sequence-specific manner. The known mechanisms for the evolution of CRISPR arrays include spacer acquisition from foreign DNA elements at the time of invasion and array erosion through spacer deletion. Here, we consider the contribution of genetic recombination between homologous CRISPR arrays to the evolution of spacer repertoire. Acquisition of spacers from exogenic arrays via recombination may confer the recipient with immunity against unencountered antagonists. For this purpose, we develop a novel method for the detection of recombination in CRISPR arrays by modeling the spacer order in arrays from multiple strains from the same species. Because the evolutionary signal of spacer recombination may be similar to that of pervasive spacer deletions or independent spacer acquisition, our method entails a robustness analysis of the recombination inference by a statistical comparison to resampled and perturbed data sets. We analyze CRISPR data sets from four bacterial species: two Gammaproteobacteria species harboring CRISPR type I and two Streptococcus species harboring CRISPR type II loci. We find that CRISPR array evolution in Escherichia coli and Streptococcus agalactiae can be explained solely by vertical inheritance and differential spacer deletion. In Pseudomonas aeruginosa, we find an excess of single spacers potentially incorporated into the CRISPR locus during independent acquisition events. In Streptococcus thermophilus, evidence for spacer acquisition by recombination is present in 5 out of 70 strains. Genetic recombination has been proposed to accelerate adaptation by combining beneficial mutations that arose in independent lineages. However, for most species under study, we find that CRISPR evolution is shaped mainly by spacer acquisition and loss rather than recombination. Since the evolution of spacer content is characterized by a rapid turnover, it is likely that recombination is not beneficial for improving phage resistance in the strains under study, or that it cannot be detected in the resolution of intraspecies comparisons.
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Affiliation(s)
- Anne Kupczok
- Institute of General Microbiology, Christian-Albrechts-University Kiel, Germany
| | - Giddy Landan
- Institute of General Microbiology, Christian-Albrechts-University Kiel, Germany
| | - Tal Dagan
- Institute of General Microbiology, Christian-Albrechts-University Kiel, Germany
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Petrova V, Chen SH, Molzberger ET, Tomko E, Chitteni-Pattu S, Jia H, Ordabayev Y, Lohman TM, Cox MM. Active displacement of RecA filaments by UvrD translocase activity. Nucleic Acids Res 2015; 43:4133-49. [PMID: 25824953 PMCID: PMC4417151 DOI: 10.1093/nar/gkv186] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 02/23/2015] [Indexed: 12/17/2022] Open
Abstract
The UvrD helicase has been implicated in the disassembly of RecA nucleoprotein filaments in vivo and in vitro. We demonstrate that UvrD utilizes an active mechanism to remove RecA from the DNA. Efficient RecA removal depends on the availability of DNA binding sites for UvrD and/or the accessibility of the RecA filament ends. The removal of RecA from DNA also requires ATP hydrolysis by the UvrD helicase but not by RecA protein. The RecA-removal activity of UvrD is slowed by RecA variants with enhanced DNA-binding properties. The ATPase rate of UvrD during RecA removal is much slower than the ATPase activity of UvrD when it is functioning either as a translocase or a helicase on DNA in the absence of RecA. Thus, in this context UvrD may operate in a specialized disassembly mode.
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Affiliation(s)
- Vessela Petrova
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Stefanie H Chen
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Eileen T Molzberger
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Eric Tomko
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | | | - Haifeng Jia
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Yerdos Ordabayev
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Timothy M Lohman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Michael M Cox
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706, USA Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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Cooper DL, Boyle DC, Lovett ST. Genetic analysis of Escherichia coli RadA: functional motifs and genetic interactions. Mol Microbiol 2015; 95:769-79. [PMID: 25484163 PMCID: PMC4357459 DOI: 10.1111/mmi.12899] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2014] [Indexed: 01/03/2023]
Abstract
The RadA/Sms protein is a RecA-related protein found universally in eubacteria and plants, implicated in processing of recombination intermediates. Here we show that the putative Zn finger, Walker A motif, KNRXG motif and Lon protease homology domain of the Escherichia coli RadA protein are required for DNA damage survival. RadA is unlikely to possess protease activity as the putative active site serine is not required. Mutants in RadA have strong synergistic phenotypes with those in the branch migration protein RecG. Sensitivity of radA recG mutants to azidothymidine (AZT) can be rescued by blocking recombination with recA or recF mutations or by overexpression of RuvAB, suggesting that lethal recombination intermediates accumulate in the absence of RadA and RecG. Synthetic genetic interactions for survival to AZT or ciprofloxacin exposure were observed between RadA and known or putative helicases including DinG, Lhr, PriA, Rep, RuvAB, UvrD, YejH and YoaA. These represent the first affected phenotypes reported for Lhr, YejH and YoaA. The specificity of these effects sheds new light on the role of these proteins in DNA damage avoidance and repair and implicates a role in replication gap processing for DinG and YoaA and a role in double-strand break repair for YejH.
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Affiliation(s)
- Deani L Cooper
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA, 02454-9110, USA
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50
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Sidorenko J, Ukkivi K, Kivisaar M. NER enzymes maintain genome integrity and suppress homologous recombination in the absence of exogenously induced DNA damage in Pseudomonas putida. DNA Repair (Amst) 2015; 25:15-26. [DOI: 10.1016/j.dnarep.2014.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/29/2014] [Accepted: 11/05/2014] [Indexed: 02/04/2023]
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