REGULATION OF MEIOTIC S PHASE BY IME2 AND A CLB5,6-ASSOCIATED KINASE IN SACCHAROMYCES-CEREVISIAE

Cyclin-dependent kinase (Cdk) mutations that prevent entry into the mi totic cell cycle of budding yeast fail to block meiotic DNA replicatio n, suggesting there may be fundamental differences between these pathw ays. However, 5 phase in meiosis was found to depend on the same B-typ e cyclins (Clb5 and Clb6) as it does in mitosis. Meiosis differs inste ad in the mechanism that controls removal of the Cdk inhibitor Sic1. D estruction of Sic1 and activation of a Clb5-dependent kinase in meioti c cells required the action of the meiosis-specific protein kinase Ime 2, thereby coupling early meiotic gene expression to control of DNA re plication for meiosis.