Rescue of MII entry in OoMastl^−/− oocytes upon Cdk1 activation and PP2A inhibition. (A) Ovulated OoMastl^−/− oocytes collected 16 h after hCG were treated with inhibitors that abolished the inhibitory phosphorylation on Cdk1 and enhanced Cdk1 activity in OoMastl^−/− oocytes. Lysate from 50 oocytes was loaded in each lane, and β-actin was used as the loading control. (B) Rescue of MII entry in OoMastl^−/− oocytes treated with PD166285 or OA. Error bars represent the SD. (C) Immunofluorescence of OoMastl^−/− oocytes treated with inhibitors showing formation of spindles and chromosome condensation. All experiments were repeated at least three times, and representative results are shown.