Figure 2. CDK-dependent inhibitory mechanisms are weakened during the MI–MII transition.

(A) Orc2 (strain yDP71) and (B) Orc6 (strain yDP120) are both transiently dephosphorylated during the MI–MII transition. ORC was detected by immunoblot during meiosis. A phosphorylation–dependent shift in electrophoretic-mobility reveals Orc2 and Orc6 phosphorylation states. The time after transfer into sporulation medium and the associated meiotic stages are indicated above each lane. For cell–cycle stage quantification, see Figure 1—figure supplement 1B (Orc2) and Figure 2—figure supplement 1A (Orc6). (C) CDC6 protein and mRNA transiently reaccumulate during the MI–MII transition (strain yDP71). Top: Cdc6 immunoblots (short and long exposures) during meiosis. Bottom: CDC6 mRNA levels were detected by northern blots during meiosis. The time after transfer into sporulation medium and the associated meiotic stages are indicated above each lane. For cell–cycle stage quantification, see Figure 2—figure supplement 1B.

Figure 2—figure supplement 1. Cells from Figure 2 proceeded synchronously through meiosis.

(A) Cell–cycle stage quantification for Figure 2B. (B) Cell–cycle stage quantification for Figure 2C.