General characteristics, molecular and genetic analysis of two new UV-sensitive mutants of Chlamydomonas reinhardtii

Two new UV-sensitive mutants of Chlamydomonas, UVS10 and UVS11, were isolated. Both behave as single nuclear mutations. UVS10 was mapped to linkage group I. UVS11 is a separate, unlinked mutation but has not yet been located to a specific linkage group. Both mutants are proficient in the excision of pyrimidine dimers from nuclear DNA. The survival of UV-irradiated UVS11 is increased when plated in the presence of 1.5 mM caffeine, similar to wild-type. Caffeine has no effect on the survival of UV-irradiated UVS10. UV-irradiated UVS11 frequently divides at least once before dying, in contrast to UVS10 or wild-type. UVS11 also exhibits a much increased frequency of mutation to streptomycin resistance after UV irradiation.