Objective       To investigate the role of cyclin D2 in hepatitis B virus (HBV) replication and explore the cyclin D2 regulation mechanism in HBV replication.       Methods       The mRNA levels of cyclin family members were analyzed by RT-PCR. The effect of cyclin D2 on the expression of HBV replicative intermediates was measured by real-time PCR and Southern blotting

and the effect of cyclin D2 on the secretion of HBsAg and HBeAg was analyzed by ELISA. The effect of cyclin D2 over-expression on HBV replication was analyzed.       Results       Among the cyclin family members

HBV replication had the most significantly impact on cyclin D2 expression

and HBV replication induced cyclin D2 replication. Cyclin D2 knockdown inhibited the expression of HBV replicative intermediates and the secretion of HBsAg and HBeAg

and cyclin D2 over-expression promoted HBV replication.       Conclusion       HBV replication promotes cyclin D2 expression

and cyclin D2 is conducive to HBV replication. This discovery can provide a novel strategy for reducing HBV infection and exploring new hepatitis B therapeutic target.