title: RecO and RecR are necessary for RecA loading in response to DNA damage and replication fork stress.
abstract: RecA is central to maintaining genome integrity in bacterial cells. Despite the near-ubiquitous conservation of RecA in eubacteria, the pathways that facilitate RecA loading and repair center assembly have remained poorly understood in Bacillus subtilis. Here, we show that RecA rapidly colocalizes with the DNA polymerase complex (replisome) immediately following DNA damage or damage-independent replication fork arrest. In Escherichia coli, the RecFOR and RecBCD pathways serve to load RecA and the choice between these two pathways depends on the type of damage under repair. We found in B. subtilis that the rapid localization of RecA to repair centers is strictly dependent on RecO and RecR in response to all types of damage examined, including a site-specific double-stranded break and damage-independent replication fork arrest. Furthermore, we provide evidence that, although RecF is not required for RecA repair center formation in vivo, RecF does increase the efficiency of repair center assembly, suggesting that RecF may influence the initial stages of RecA nucleation or filament extension. We further identify single-stranded DNA binding protein (SSB) as an additional component important for RecA repair center assembly. Truncation of the SSB C terminus impairs the ability of B. subtilis to form repair centers in response to damage and damage-independent fork arrest. With these results, we conclude that the SSB-dependent recruitment of RecOR to the replisome is necessary for loading and organizing RecA into repair centers in response to DNA damage and replication fork arrest.
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Justin S
authors.initials: JS
authors.lastname: Lenhart
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Eileen R
authors.initials: ER
authors.lastname: Brandes
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Jeremy W
authors.initials: JW
authors.lastname: Schroeder
authors.affiliation: Vahlteich Medicinal Chemistry Core, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Roderick J
authors.initials: RJ
authors.lastname: Sorenson
authors.affiliation: Vahlteich Medicinal Chemistry Core, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Hollis D
authors.initials: HD
authors.lastname: Showalter
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA lasimm@umich.edu.
authors.forename: Lyle A
authors.initials: LA
authors.lastname: Simmons
mesh_terms: D001412:Bacillus subtilis / Q000166:cytology / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair; D004261:DNA Replication / Q000187:drug effects*; D004269:DNA, Bacterial / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins; D009154:Mutation; D011938:Rec A Recombinases / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins; D014498:Uracil / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C065831:RecR protein, Bacteria; D049452:Green Fluorescent Proteins; C011284:6-(4-hydroxyphenylhydrazino)uracil; D014498:Uracil; D011938:Rec A Recombinases