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

Summary A double mutant being thermoconditionally defective in mutation induction as well as in repair of pre-lethal UV-induced DNA damage (rev2^ts) and deficient in excision repair (rad3-2) was studied in temperature-shift experiments. The influence of inhibitors of DNA replication (hydroxyurea, aphidicolin) was determined. Additionally, an analysis of the dose-response pattern of mutation induction (mutation kinetics) at several ochre alleles was carried out. It was concluded that the UV-inducible REV2 dependent mutagenic repair process is not induced in excision-deficient cells. In excision-deficient cells, REV2 dependent mutation fixation is slow and mostly postreplicative though not dependent on DNA replication. The REV2 mediated mutagenic process could be separated from the repair function.