Rad24 is essential for proliferation of diploid cells in fission yeast

The rad24(+) gene of Schizosaccharomyces pombe encodes a ubiquitously expre ssed 14-3-3 protein. We report here that Delta rad24 cells displayed a defe ct in diploid colony formation, although they conjugated efficiently. We fo und that a cumulative deletion of mei2(+) gene almost completely suppressed this defect, and demonstrated using two-hybrid analysis that Rad24 protein directly associates with Mei2 protein by recognizing Ser-438 which is a ph osphorylation target of Pat1 kinase, We conclude that constitutive progress ion to meiosis, caused by lack of Mei2 inhibition due to the absence of Rad 24 protein, is the primary cause of the proliferative deficiency observed i n Delta rad24 cells, (C) 2000 Federation of European Biochemical Societies.