FIG. 7.

MPF activity stimulates endogenous cyclin B1 mRNA polyadenylation in the absence of MAPK activity. Immature oocytes were injected with RNA encoding MKP, as indicated, and left for 14 h to express the protein. The oocytes were then either stimulated with progesterone (Prog), injected with cyclin B1 protein, or left untreated (Imm). Pools of oocytes were taken when the controls had reached GVBD₅₀, and both RNA and protein lysates were prepared. (A) Endogenous cyclin B1 mRNA polyadenylation was analyzed as described in the legend to Fig. 6. (B) Kinase activities are as described in the legend to Fig. 1.