Mycobacterium tuberculosis RecG Protein but Not RuvAB or RecA Protein Is Efficient at Remodeling the Stalled Replication Forks

Thakur, Roshan Singh; Basavaraju, Shivakumar; Khanduja, Jasbeer Singh; Muniyappa, K.; Nagaraju, Ganesh

doi:10.1074/jbc.m115.671164

Cited by 13 publications

(11 citation statements)

References 91 publications

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“…Similarly, RecG is a structure‐specific helicase that binds and unwinds branched DNA structures that are intermediates of DNA repair/recombination/replication . Previously we showed that M. tuberculosis RecG (MtRecG) efficiently remodels the stalled replication forks . To test whether MtRecG can also resolve G4 DNA structures in vitro , we incubated increasing concentrations of MtRecG with TPB‐G4‐3′T15 (15‐nt 3′‐overhang) structures.…”

Section: Resultsmentioning

confidence: 99%

Mycobacterium tuberculosis UvrD1 and UvrD2 helicases unwind G‐quadruplex DNA

et al. 2019

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Unresolved G‐quadruplex (G4) DNA secondary structures impede DNA replication and can lead to DNA breaks and to genome instability. Helicases are known to unwind G4 structures and thereby facilitate genome duplication. Escherichia coli UvrD is a multifunctional helicase that participates in DNA repair, recombination and replication. Previously, we had demonstrated a novel role of E. coli UvrD helicase in resolving G4 structures. Mycobacterium tuberculosis genome encodes two orthologs of E. coli UvrD helicase, UvrD1 and UvrD2. It is unclear whether UvrD1 or UvrD2 or both helicases unwind G4 DNA structures. Here, we demonstrate that M. tuberculosis UvrD1 and UvrD2 unwind G4 tetraplexes. Both helicases were proficient in resolving previously characterized tetramolecular G4 structures in an ATP hydrolysis and single‐stranded 3′‐tail‐dependent manner. Notably, M. tuberculosis UvrD1 and UvrD2 were efficient in unwinding G4 structures derived from the potential G4 forming sequences present in the M. tuberculosis genome. These data suggest an extended role for M. tuberculosis UvrD1 and UvrD2 helicases in resolving G4 DNA structures and provide insights into the maintenance of genome integrity via G4 DNA resolution.

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Section: Resultsmentioning

confidence: 99%

Mycobacterium tuberculosis UvrD1 and UvrD2 helicases unwind G‐quadruplex DNA

et al. 2019

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“…Purified RecG protein has 3′–5′ helicase and nucleic acid translocase activities. In vitro , it can bind and unwind synthetic model Holliday junctions and various other types of branched DNA substrates including replication forks, D‐loops and R‐loops . Unlike most other helicases, this enzyme unwinds DNA by translocating on dsDNA rather than on ssDNA.…”

Section: Recg Protein Unwinds and Remodels Branched Dna Molecules In mentioning

confidence: 99%

“…This RecG‐catalysed replication fork reversal reaction has been observed using an oligonucleotide substrate with nascent strands annealed to both the leading‐ and lagging‐strand templates , a replication fork in supercoiled plasmid DNA and a replication fork blocked at a DNA lesion in an in vitro replication system where the DNA polymerase and the replicative helicase remain associated with the DNA . These studies have led to the opinion that replication fork reversal is an important biochemical activity of RecG . RecG can catalyse this reaction thanks to its unusual structure .…”

Section: Recg Protein Unwinds and Remodels Branched Dna Molecules In mentioning

confidence: 99%

RecG controls DNA amplification at double‐strand breaks and arrested replication forks

Azeroglu

Leach

2017

FEBS Letters

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DNA amplification is a powerful mutational mechanism that is a hallmark of cancer and drug resistance. It is therefore important to understand the fundamental pathways that cells employ to avoid over‐replicating sections of their genomes. Recent studies demonstrate that, in the absence of RecG, DNA amplification is observed at sites of DNA double‐strand break repair (DSBR) and of DNA replication arrest that are processed to generate double‐strand ends. RecG also plays a role in stabilising joint molecules formed during DSBR. We propose that RecG prevents a previously unrecognised mechanism of DNA amplification that we call reverse‐restart, which generates DNA double‐strand ends from incorrect loading of the replicative helicase at D‐loops formed by recombination, and at arrested replication forks.

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“…But what might drive fork reversal and how might replication resume? A possible scenario emerged when E. coli RecG protein was shown to catalyse the interconversion of fork and Holliday junction structures in vitro (McGlynn and Lloyd 2000 ), a result recapitulated with RecG proteins from other bacteria (Zegeye et al 2012 ; Thakur et al 2015 ). Indeed, recent in vitro studies exploiting substrates and conditions that more closely mimic the situation likely to be encountered at a stalled fork in vivo confirmed that RecG is able to drive fork reversal and revealed that dissociation of the replisome is probably not a pre-requisite (Gupta et al 2014 ).…”

Section: Re-starting Replication At Stalled or Damaged Forksmentioning

confidence: 99%

25 years on and no end in sight: a perspective on the role of RecG protein

Lloyd

Rudolph

2016

Curr Genet

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The RecG protein of Escherichia coli is a double-stranded DNA translocase that unwinds a variety of branched substrates in vitro. Although initially associated with homologous recombination and DNA repair, studies of cells lacking RecG over the past 25 years have led to the suggestion that the protein might be multi-functional and associated with a number of additional cellular processes, including initiation of origin-independent DNA replication, the rescue of stalled or damaged replication forks, replication restart, stationary phase or stress-induced ‘adaptive’ mutations and most recently, naïve adaptation in CRISPR-Cas immunity. Here we discuss the possibility that many of the phenotypes of recG mutant cells that have led to this conclusion may stem from a single defect, namely the failure to prevent re-replication of the chromosome. We also present data indicating that this failure does indeed contribute substantially to the much-reduced recovery of recombinants in conjugational crosses with strains lacking both RecG and the RuvABC Holliday junction resolvase.Electronic supplementary materialThe online version of this article (doi:10.1007/s00294-016-0589-z) contains supplementary material, which is available to authorized users.

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Mycobacterium tuberculosis RecG Protein but Not RuvAB or RecA Protein Is Efficient at Remodeling the Stalled Replication Forks

Cited by 13 publications

References 91 publications

Mycobacterium tuberculosis UvrD1 and UvrD2 helicases unwind G‐quadruplex DNA

Mycobacterium tuberculosis UvrD1 and UvrD2 helicases unwind G‐quadruplex DNA

RecG controls DNA amplification at double‐strand breaks and arrested replication forks

25 years on and no end in sight: a perspective on the role of RecG protein

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