Effect of ruv mutations on recombination and DNA repair in Escherichia coli K12

Abstract

Mutation of the ruv gene of E. coli is associated with sensitivity to radiation, and filamentous growth after transient inhibition of DNA synthesis. The filamentation of ruv strains is abolished by mutations in sfiA or sfiB that prevent SOS induced inhibition of cell division, but this does not restore resistance to UV radiation. Double mutants carrying both ruv and uvr mutations are considerably more sensitive to UV radiation than the single mutants, but there is no additive effect of ruv with recA, recF, recB, or recC mutations. ruv mutations have little effect on conjugal recombination in wild-type strains but confer recombination deficiency and extreme sensitivity to ionizing radiation in recBC sbcB strains. These results, together with the fact that ruv strains are excision proficient and mutable by UV light, are interpreted to suggest that the ruv + product is involved in recombinational repair of damaged DNA rather than in cell division as suggested by Otsuji et al. (1974).

Regression of Replication Forks Stalled by Leading-strand Template Damage

“…This observation runs counter to the common view of RuvABC being a resolvasome (60), which is supported by considerable data; the phenotypes of mutations in ruvA, ruvB, and ruvC are similar (61,62). Monoclonal antibodies against RuvA, RuvB, or RuvC inhibit resolution of a HJ in a reconstituted branch migration system (60).…”

Molecular analysis of the Escherichia coli ruvC gene, which encodes a Holliday junction-specific endonuclease

“…Therefore, we concluded that the ruv-53 mutation is distinct from the ruvA and ruvB mutations; this is in agreement with the report by Sharples et al (25), who showed that the ruv-SJ and ruv-53 mutations are complemented by the plasmids carrying the chromosomal fragments upstream of the ruvAB operon. They designated these mutations ruvC, because their phenotypes are very similar to those of ruvB and ruvAB mutants; i.e., ruvC mutants are sensitive to DNA-damaging agents and are defective in recombination when they carry additional mutations in recBC sbcA or recBC sbcBC (11,12).…”

“…CS40a (11) was used as a ruv+ control strain. The Ruv phenotype was examined by the sensitivity of the mutant to UV irradiation.…”

“…These mutants are also sensitive to various DNA-damaging agents such as UV, ionizing radiation, and some chemical mutagens, and they form multinucleated cells after treatment with low doses of such agents (18)(19)(20)32). Although ruv mutations have little effect on conjugal recombination in otherwise wild-type strains, they reduce the ability of recombination in recBC sbcA and recBC sbcBC strains (11)(12)(13). This evidence suggests that the ruv locus may be involved in recombinational repair by the RecE and the RecF pathways.…”

Evidence that Phenylalanine 69 in Escherichia coliRuvC Resolvase Forms a Stacking Interaction during Binding and Destabilization of a Holliday Junction DNA Substrate

“…Genetic analyses indicate that RuvC resolvase plays a defined role in processing recombination and repair intermediates (7)(8)(9)(10)(11). In vitro studies confirm that RuvC specifically interacts with and resolves Holliday junctions by endonucleolytic cleavage (12,13).…”