Resolution of Holliday intermediates in recombination and DNA repair: indirect suppression of ruvA, ruvB, and ruvC mutations.
AUTOR(ES)
Mandal, T N
RESUMO
The ruvA, ruvB, and ruvC genes of Escherichia coli provide activities that catalyze branch migration and resolution of Holliday junction intermediates in recombination. Mutation of any one of these genes interferes with recombination and reduces the ability of the cell to repair damage to DNA. A suppressor of ruv mutations was identified on the basis of its ability to restore resistance to mitomycin and UV light and to allow normal levels of recombination in a recBC sbcBC strain carrying a Tn10 insertion in ruvA. The mutation responsible was located at 12.5 min on the genetic map and defines a new locus which has been designated rus. The rus suppressor works just as well in recBC sbcA and rec+ sbc+ backgrounds and is not allele specific. Mutations in ruvB and ruvC are suppressed to an intermediate level, except when ruvA is also inactive, in which case suppression is complete. In all cases, suppression depends on RecG protein, a DNA-dependent ATPase that catalyzes branch migration of Holliday junctions. The rus mutation activates an additional factor that probably works with RecG to process Holliday junction intermediates independently of the RuvAB and RuvC proteins. The possibility that this additional factor is a junction-specific resolvase is discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=204872Documentos Relacionados
- SOS-inducible DNA repair proteins, RuvA and RuvB, of Escherichia coli: functional interactions between RuvA and RuvB for ATP hydrolysis and renaturation of the cruciform structure in supercoiled DNA.
- Interaction of Escherichia coli RuvA and RuvB proteins with synthetic Holliday junctions.
- Dissociation of RecA filaments from duplex DNA by the RuvA and RuvB DNA repair proteins.
- RuvA and RuvB proteins of Escherichia coli exhibit DNA helicase activity in vitro.
- Resolution of Holliday junctions in genetic recombination: RuvC protein nicks DNA at the point of strand exchange.