Characterization of a new radiation-sensitive mutant, Escherichia coli K-12 radC102.
A new radiation-sensitive mutant, radC , has been isolated. The radC gene is located at 81.0 min on the Escherichia coli K-12 linkage map. The radC mutation sensitized cells to uv radiation, but unlike most DNA repair mutations, sensitization to X rays was observed only for rich medium-grown cells. For cells grown in rich medium, the radC mutant was normal for gamma-radiation mutagenesis, but showed less uv-radiation mutagenesis than the wild-type strain; it showed normal amounts of X- and uv-radiation-induced DNA degradation, and it was approximately 60% deficient in recombination ability. The radC strain was normal for host cell reactivation of gamma-and uv-irradiated bacteriophage lambda; the radC mutation did not sensitize a recA strain, but did sensitize a radA and a polA strain to X and uv radiation and a uvrA strain to uv radiation. Therefore, we suggest that the radC gene product plays a role in the growth medium-dependent, recA gene-dependent repair of DNA single-strand breaks after X irradiation, and in postreplication repair after uv irradiation.
D002470:Cell Survival / Q000528:radiation effects; D002874:Chromosome Mapping; D004307:Dose-Response Relationship, Radiation; D004926:Escherichia coli / Q000235:genetics*; D005720:Gamma Rays; D005798:Genes, Bacterial; D009154:Mutation; D011831:Radiation Genetics; D011836:Radiation Tolerance; D014466:Ultraviolet Rays