Effect of an umuC mutation on the SOS response in E. coli cells exposed to ultraviolet and #gamma#-radiation

摘要

The kinetics of the SOS induction in E. coli cells of wild type and deficient in umuC gene exposed to UV and #gamma#-rays were analysed. In the presence of UmuC protein SOS induction was 3-5.5 times lower and delayed for about 30 minutes after both UV and #gamma#-rays. It was shown that decrease of the SOS induction in wild type cells irradiated by UV was due to more effective elimination of the photolesions from DNA by excision repair system. UmuCD-dependent inhibition of DNA replication was discussed as a possible mechanism allowing additional time for error-free repair.