Transcript levels of the Saccharomyes cerevisiae DNA repair gene RAD23 increase in response to UV light andin meiosis but remain constant in the mitotic cell cycle

The RAD23 gene of Saccharomyces cerevisiae is required for excision-repair of UV damaged DNA. In this paper, we determine the location of the RAD23 genein a cloned DNA fragment, identify the 1.6 kb RAD23 transcript, and examine RAD23 transcript levels in UV damaged cells, during the mitotic cell cycle, and in meiosis. The RAD23 mRNA levels are elevated 5-fold between 30 to 60 min after 37 J/m² of UV light. RAD23 mRNA levels rise over 6-fold during meiosis at a stagecoincident with high levels of genetic recombination. This response is specific to sporulation competent MATa/MATα diploid cells, and is not observed in asporogenous MATa/MATα diploids. RAD23 mRNA levels, however, remain constant during the mitotic cell cycle.