Role of DNA polymerase II in the tolerance of thymine dimers remaining unexcised in UV-irradiated Escherichia coli exposed to pre-UV nutritional stress

Nutritional stress applied prior to UV-irradiation to E. coli 15 555-7 reduced thymine dimer excision and inhibited post-UV incorporation of thymidine in polB+ as well as in polB− cells. However, the pre-UV-stressed polB+ cells were significantly more UV-resistant and after UV synthesized larger DNA molecules than the pre-UV-stressed polB− cells. The data suggest that DNA polymerase II is involved in the tolerance of unremoved thymine dimers.