The Ruvab Branch Migration Translocase And Recu Holliday Junction Resolvase Are Required For Double-Stranded Dna Break Repair In Bacillus Subtilis

In models of Escherichia coli recombination and DNA repair, thin RuvABC complex directs the branch migration and resolution of Holliday junction DNA. To probe the validity of the E. coli paradigm, we examined the impact Of mutations in Delta ruvAB and Delta recU (a ruvC functional analog) on DNA repair. Under standard transformation conditions we failed to construct Delta ruvAB Delta recG, Delta recU Delta recAB, Delta recU Delta rerG, or Delta recU Delta recJ strains. However, Delta ruvAB could be combined with addAB (recBCD), recF, recH, Delta recS, Delta recQ, Delta recJ mutations. The Delta ruvAB and Delta recU mutations tendered cells extremely sensitive to DNA-damaging agents,, although less sensitive than Delta recA strain. When dam-aged cells were analyzed, we found that RecU was recruited to defined doable stranded DNA breaks (DSBs) and colocalized with RecM RecU localized to these centers at a later time point during DSB repair and formation was dependent on RuvAW in addition; expression of RecU in an E. coli ruvC mutant restored hill resistance to Uv light only when the ruvAB genes were present The results demonstate that, as with E. coli RuvABG, RuvAB targets RecU to recombination intermediates and that all three proteins are required for repair of DSN arising from lesions in chromosomal DNA.