H: A diagram showing role of CCR4-NOT deadenylase complex in targeting maternal mRNA decay. During the onset of oocyte meiotic resumption, MAPK cascade and CPEB1 triggers translational activation of maternal transcripts including those encoding BTG4, CNOT7, CNOT6L, and ZFP36L CNOT6L and other CCR4-NOT components are important downstream effectors of ERK1 and ERK2 in the regulation of spindle assembly and meiotic cell cycle progression in oocytes. During oocyte maturation, RNA-binding protein ZFP36L2 associates with CNOT6L and functions as a CCR4-NOT adaptor in triggering the degradation of ARE-containing transcripts. At a later stage of MZT, an alternative adaptor BTG4 binds to translation initiation factor eIF4E and thereby recruits the CCR4-NOT complex to the actively translated mRNAs. The stepwise recruitment of different adaptors by different catalytic subunits mediates stage-specific degradation of maternal mRNAs by the CCR4-NOT deadenylase. The question mark means that the direct involvement of CNOT6L in BTG4-mediated MZT process remains inconclusive because Cnot6l null oocytes had severe meiosis defects before MZT 