title: Direct rescue of stalled DNA replication forks via the combined action of PriA and RecG helicase activities.
abstract: The PriA protein of Escherichia coli plays a key role in the rescue of replication forks stalled on the template DNA. One attractive model of rescue relies on homologous recombination to establish a new fork via PriA-mediated loading of the DnaB replicative helicase at D loop intermediates. We provide genetic and biochemical evidence that PriA helicase activity can also rescue a stalled fork by an alternative mechanism that requires manipulation of the fork before loading of DnaB on the lagging strand template. This direct rescue depends on RecG, which unwinds forks and Holliday junctions and interconverts these structures. The combined action of PriA and RecG helicase activities may thus avoid the potential dangers of rescue pathways involving fork breakage and recombination.
authors.affiliation: Institute of Genetics, Queen's Medical Centre, University of Nottingham, United Kingdom.
authors.forename: Amanda V
authors.initials: AV
authors.lastname: Gregg
authors.forename: Peter
authors.initials: P
authors.lastname: McGlynn
authors.forename: Razieh P
authors.initials: RP
authors.lastname: Jaktaji
authors.forename: Robert G
authors.initials: RG
authors.lastname: Lloyd
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D000483:Alleles; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004249:DNA Damage; D004265:DNA Helicases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004261:DNA Replication / Q000502:physiology* / Q000528:radiation effects; D004269:DNA, Bacterial / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D053488:DnaB Helicases; D004706:Endodeoxyribonucleases / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D046911:Macromolecular Substances; D008957:Models, Genetic; D009690:Nucleic Acid Conformation; D013698:Templates, Genetic; D014466:Ultraviolet Rays
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; C061260:RuvB protein, Bacteria; C069806:ruvC protein, E coli; C071446:RecG protein, E coli; D004706:Endodeoxyribonucleases; C071059:Holliday junction DNA helicase, E coli; D000251:Adenosine Triphosphatases; C506730:dnaB protein, E coli; C506743:priA protein, E coli; D004265:DNA Helicases; D053488:DnaB Helicases