MEIOTIC ROLE OF SWI6 IN SACCHAROMYCES-CEREVISIAE

The transcript levels of DNA replication genes and some recombination genes in Saccharomyces cerevisiae fluctuate and peak at the G1/S bound ary in the mitotic cell cycle. This fluctuation is regulated by MCB (M lul cell cycle box) elements which are bound by the DSC1/MBF1 complex consisting of Swi6 and Mbp1, It is also known that some of the MCB-reg ulated genes are induced by treatment with DNA damaging agents and in meiosis, In this report, the function of SW16 in meiosis was investiga ted. Delta swi6 cells underwent sporulation as did wild-type cells. Ho wever, the deletion mutant cells showed reduced spore viability and lo wer frequency of recombination. The transcript levels of the recombina tion genes RAD51 and RAD54, which have MCB elements, were reduced in D elta swi6 cells, The transcript levels of SW16 itself were also induce d and declined in meiosis, Furthermore, an increased dosage of SW16 en hanced the transcript level of the RAD51 gene and also the recombinati on frequency in meiosis, These results suggest that SW16 enhances the expression level of the recombination genes in meiosis in a dosage-dep endent manner, which results in an effect on the frequency of meiotic recombination.