Analysis of mutagenic DNA repair in a thermoconditional repair mutant of Saccharomyces cerevisiae

Summary

The time course of REV2 dependent recovery from prelethal UV damage and UV-induced locus-specific reversion of the his5-2 allele was determined in temperatureshift experiments by use of a thermoconditional allele of the rev2 gene (rad5-8, rev2 ^ts). In UV-irradiated, exponentially growing rev2 ^ts cells the REV2 dependent repair activity persists for up to 8 h at permissive temperature (23° C), while the REV2 dependent mutagenic process is mostly completed within 2 h. The REV2 dependent process in exponentially growing cells is highly impaired by inhibition of protein synthesis. However, a REV2 dependent repair activity independent of de novo synthesis is detectable, even in the presence of up to 200 μg/ml cycloheximide, a response not found in stationary phase cells. Thus, the REV2 dependent process seems to be partially constitutive in exponentially growing cells. Additionally, exponentially growing rev2 ^ts cells were considerably more UV-sensitive at restrictive temperature (36°C) than were stationary phase cells.