title: [Action of plasmid ColIb-P9 on the survival after ultraviolet irradiation and on the mutagenesis of the imiC, uvm, recL, uvrE and tif1 sfiA lexA spr mutants of Escherichia coli K-12 cells].
abstract: To clarify the mechanisms whereby the ColIb-P9 plasmid affects DNA repair processes, its effect was studied in mutant Escherichia coli K-12 cells with altered mutagenesis and DNA repair. The plasmid was shown to protect umuC, uvm, recL and uvrE mutants after UV irradiation. The frequency of UV-induced his+ revertants increased in the presence of the plasmid in umuC, uvm and recL mutant cells. The ColIb-P9 plasmid completely restored the UV mutability and survival of umuC mutants. These results suggest that the ColIb-P9 plasmid may encode a product similar to that of the umuC gene. In the tif1 sfiA lexA spr mutant cells where SOS functions are constitutively expressed, the ColIb-P9 plasmid increased the number of his+ revertants several times. This suggests that the action of ColIb-P9 is probably brought about not via the derepression of the recA gene but at the subsequent stages of the recA+lexA+-dependent DNA error-prone repair.
mesh_terms: D004260:DNA Repair / Q000528:radiation effects; D004269:DNA, Bacterial / Q000528:radiation effects*; D004926:Escherichia coli / Q000235:genetics* / Q000528:radiation effects; D005786:Gene Expression Regulation / Q000528:radiation effects; D005798:Genes, Bacterial / Q000528:radiation effects*; D009154:Mutation; D010957:Plasmids / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D004269:DNA, Bacterial
vernacular_title: Deĭstvie plazmidy ColIb-P9 na vyzhivaemost' posle ul'trafioletovogo oblucheniia i mutagenez imiC, uvm, recL, uvrE, tif1 sfiA LexA spr-mutantov kletok Escherichia coli K-12.