The CCR4-NOT complex suppresses untimely translational activation of maternal mRNAs.

Control of mRNA poly(A) tail has central role to regulate mRNA metabolism: translation efficiency and mRNA stability. Gene expression in maturing oocytes largely relies on the regulation of mRNA metabolism as they are transcriptionally silent. The CCR4-NOT complex is a major deadenylase for mammals and regulates poly(A) tails of maternal mRNAs, however their function to translational regulation was not well understood. Here we show that CCR4-NOT suppresses translational activity of maternal mRNAs during oocyte maturation. Oocytes which lack entire deadenylase activity of CCR4-NOT by genetic deletion of its catalytic subunits: CNOT7 and CNOT8 showed increase of both expression of maternal mRNAs and translational activity of them during oocyte maturation. Comparative gene expression analysis using RNA-seq data from CNOT7&8 KO oocytes and Zp3-Cre control.