Effects of the rad52 gene on recombination in Saccharomyces cerevisiae. [Comparison of. gamma. -, uv-induced meiotic and spontaneous mitotic recombination]

Effects of the rad52 mutation in Saccharomyces cerevisiae on meiotic, gamma-ray-induced, UV-induced and spontaneous mitotic recombination were studied. The rad52/rad52 diploids undergo premeiotic DNA synthesis; sporulation occurs but inviable spores are produced. Both intra and intergenic recombination during meiosis were examined in cells transferred from sporulation medium to vegetative medium at different time intervals. No intragenic recombination was observed at the his1-1/his1-315 and trp5-2/trp5-48 heteroalleles. Gene-centromere recombination also was not observed in rad52/rad52 diploids. No gamma-ray- or UV-induced intragenic mitotic recombination is seen in rad52/rad52 diploids. The rate of spontaneous mitotic recombination is lowered five-fold at the his1-1/his1-315 and leu1-c/leu1-12 heteroalleles. Spontaneous reversion rates of both his1-1 and his1-315 were elevated 10 to 20 fold in rad52/rad52 diploids.-The RAD52 gene function is required for spontaneous mitotic recombination, UV- and gamma-ray-induced mitotic recombination and meiotic recombination.