CDC2A (CDK1)-mediated phosphorylation of MSY2 triggers maternal mRNA degradation during mouse oocyte maturation.
Degradation of maternal mRNA is thought to be essential to undergo the maternal-to-embryonic transition. Messenger RNA is extremely stable during oocyte growth in mouse and MSY2, an abundant germ cell-specific RNA-binding protein, likely serves as a mediator of global mRNA stability. Oocyte maturation, however, triggers an abrupt transition in which most mRNAs are significantly degraded. We report that CDC2A (CDK1)-mediated phosphorylation of MSY2 triggers this transition. Injecting Cdc2a mRNA, which activates CDC2A, overcomes milrinone-mediated inhibition of oocyte maturation, induces MSY2 phosphorylation and the maturation-associated degradation of mRNAs. Inhibiting CDC2A following its activation with roscovitine inhibits MSY2 phosphorylation and prevents mRNA degradation. Expressing non-phosphorylatable dominant-negative forms of MSY2 inhibits the maturation-associated decrease in mRNAs, whereas expressing constitutively active forms induces mRNA degradation in the absence of maturation and phosphorylation of endogenous MSY2. A positive-feedback loop of CDK1-mediated phosphorylation of MSY2 that leads to degradation of Msy2 mRNA that in turn leads to a decrease in MSY2 protein may ensure that the transition is irreversible.
Medvedev
Sergey
S
Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
Yang
Juxiang
J
Hecht
Norman B
NB
Schultz
Richard M
RM
D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D051379:Mice; D009865:Oocytes / Q000378:metabolism*; D010766:Phosphorylation; D020871:RNA Stability; D023121:RNA, Messenger, Stored / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism
D023121:RNA, Messenger, Stored; D016601:RNA-Binding Proteins; C116047:Ybx2 protein, mouse; D016203:CDC2 Protein Kinase; D012260:Ribonucleases