Fig. 8.

A schematic model of roles of Cnot3-mediated deadenylation in postnatal liver functional maturation. Expression of cell cycle-related and fetal liver mRNAs decreases as the liver matures. Cnot3-mediated deadenylation contributes to downregulation of those mRNAs during postnatal days. Molecules from several unusually stabilized mRNAs, which are involved in cell cycle progression and cytokinesis, lead to an increase of mitotic and mononucleate hepatocytes in Cnot3^−/− livers. Transcription of mature liver genes is insufficient in Cnot3^−/− livers. This is partly due to antagonistic effects of cell cycle-related molecules, such as Cdk activators and p53, on transcription factors responsible for liver maturation. Decreased expression of mature liver mRNAs is relevant to impaired liver function and damage.