Geminin stabilizes Cdt1 during maturation. Western analysis of Cdc27, cyclin B1, Geminin, and Cdt1 proteins at the indicated times. A, during meiotic maturation. B, in the presence of exogenous Geminin during maturation. C, in the presence of CHX. D, in the presence of CHX and exogenous Geminin. The Mcm4 protein served as a loading control. Asterisk indicates exogenous Geminin.