Cyclin D2 plays a regulatory role in HBV replication.

Hepatitis B virus (HBV) infection is the leading cause of liver diseases. However, the molecular mechanisms of HBV infection and carcinogenesis have not been fully elucidated. In this study, we found that cyclin D2 was upregualted in HBV-expressing cells and liver tissues of HBV-transgenic mice. Gene silencing of cyclin D2 inhibited HBV DNA replicative intermediates, 3.5kb mRNA, core protein level, as well as the secretions of HBsAg and HBeAg. On the contrary, overexpression of cyclin D2 promoted HBV replication. Furthermore, cyclin D2 regulated HBV replication by enhancing the activity of HBV core and Sp1 promoters by targeting transcription factor CREB2. Silencing of CREB2 abolished enhancement of HBV replication induced by cyclin D2. Together, our study has uncovered a positive role of cyclin D2 in HBV replication. It is conceivable that therapeutic application of cyclin D2 inhibitor in HBV infection therapy.