Regulation of meiosis: from DNA binding protein to protein kinase

The transition from mitotic cell division to meiosis in yeast is governed by both the mating-type genes and signals from the environment. Analysis of mutants that are unable to regulate entry into meiosis has identified many genes that function in this process and in some cases, the biochemical activity of their protein products has been described. At least two of the the mating-type genes of Saccharomyces cerevisiae encode DNA binding proteins that regulate transcription of unlinked genes required for entry into meiosis. Meiotic development of the distantly related yeast, Schizosaccharomyces pombe, is also controlled by the mating-type genes but in this yeast, their role is to regulate expression of a protein that acts as an inhibitor of a protein kinase. The ability to use the powerful tool of genetics in yeast has provided us with many new insights into the problem of meiotic development.