title: Repair promoted by plasmid pKM101 is different from SOS repair.
abstract: In E. coli K12 bacteria carrying plasmid pKM101, prophage lambda was induced at UV doses higher than in plasmid-less parental bacteria. UV-induced reactivation per se was less effective. Bacteria with pKM101 showed no alteration in their division cycle. Plasmid pKM101 coded for a constitutive error-prone repair different from the inducible error-prone repair called SOS repair. Plasmid pKM101 protected E. coli bacteria from UV damage but slightly sensitized them to X-ray lesions. Protection against UV damage was effective in mutant bacteria deficient in DNA excision-repair provided that the recA, lexA and uvrE genes were functional. Survival of phages lambda and S13 after UV irradiation was enhanced in bacteria carrying plasmid pKM101; phage lambda mutagenesis was also increased. Plasmid pKM101 repaired potentially lethal DNA lesions, although wild-type DNA sequences may not necessarily be restored; hence the mutations observed are the traces of the original DNA lesions.
mesh_terms: D004260:DNA Repair; D004269:DNA, Bacterial / Q000528:radiation effects*; D004926:Escherichia coli / Q000235:genetics*; D009154:Mutation; D010957:Plasmids; D011836:Radiation Tolerance; D014466:Ultraviolet Rays; D014965:X-Rays
chemical_list: D004269:DNA, Bacterial