Objective   To study on the function of mitogen-activated protein kinase(MAPK)and mitosis-promoting factor(MPF)in the first mitosis of mouse fertilized eggs and the relationship between them.

  Methods   Inhibiting the activity of MAP K and MPF by their inhibitor U0126 and roscovitine, we assayed MAP K and MPF activity in the first mitosis and simultaneously detected the influence of the two kinase activity on the early development of fertilized egg by morphology.

  Results   During the first mitosis in normal control group, MAPK and MPF could be activated transiently.In U0126 group, the activity of MAPK was inhibited by U0126 induced that fertilized eggs could not complete mitosis and stayed in metaphase, but MPF activation had not been influenced.In roscovitine group, the activity of MPF was inhibited by roscovitine caused that fertilized eggs could not complete mitosis and stayed in metaphase, whatever MAPK maintain inactive state.

  Conclusion   MAPK and MPF activation are required for mouse normal mitotic progression.MPF is involved in the activation of MAPK in metaphase.