Fig. 6.

S67-thiophosphorylated ARPP19 requires the synthesis of either Cyclin B or Mos to promote meiotic resumption. (A) Prophase-arrested oocytes (Pro) were either injected with antisense oligonucleotides directed against Cyclin B mRNA or incubated with U0126, or simultaneously subjected to both treatments. Oocytes were then either treated with progesterone (Pg) or injected with S67-thiophosphorylated WT-GST-ARPP (WT*). Oocytes were collected at the time of GVBD and lysates were western blotted for Gwl, Cyclin B1, phosphorylated MAPK (pMAPK) and Y15-phosphorylated Cdk1 (pY15-Cdk1). (B) Prophase-arrested oocytes (Pro) were incubated or not with cycloheximide (CHX) then induced to mature by adding progesterone (Pg) or by injecting either Mos or S67-thiophosphorylated WT-GST-ARPP (WT*) or both. Oocytes were collected at the time of GVBD and lysates were analyzed by western blot for Gwl, Cyclin B2, Cyclin B1, phosphorylated MAPK (pMAPK) and Y15-phosphorylated Cdk1 (pY15-Cdk1).