F. Confocal images of JC-1 monomers (green) and aggregates (red) of GV and MII oocytes from wild-type (WT) and Erk1/2oo-/- oocytes (n=3 mice in each group). Erk1/2oo-/- oocytes exhibited big and multiple polar bodies, indicated by red arrows. Hoechst 33342 (blue) was co-stained to represent nucleus or chromosome. Scale bar=10 µm. 