Fig. 6. Stage IV and stage VI oocytes were stimulated by progesterone or injected with either GST-cyclin B or Xenopus Mos protein or both GST-cyclin B and Mos. Oocytes were collected and western blotted with antibodies against cyclin B2, the Tyr15-phosphorylated form of Cdc2 (P-Tyr-Cdc2), the active phosphorylated form of MAPK (P-MAPK) and Rsk.