Synthesis of inducible enzymes in irradiated yeast cells. Ultraviolet effects on transcription and the influence of recovery processes.

The induced synthesis of arginase was measured in several yeast strains after ultraviolet light irradiation. There was an exponential dose-related reduction which was the same in all cell lines tested. This sensitivity is compatible with the size of the arginase structural gene if it is assumed that one pyrimidine dimer suffices for blocking transcription. The ultraviolet-induced synthesis inhibition is susceptible to photoreactivation and liquid holding recovery. The latter process is absent in a rad2 mutant and reduced in a rad9 mutant.