Hepatitis B virus DNA polymerase displays an anti-apoptotic effect by interacting with elongation factor 1-alpha2 in hepatoma cells.

Hepatitis B virus (HBV) genome P-encoded protein-HBV DNA polymerase (Pol) has long been known as a reverse transcriptase during the HBV replication. In this study, we aimed at investigating the impact of HBV Pol on host cellular processes, mainly apoptosis, and the underlying mechanisms. We showed a marked reduction in apoptotic rates in the HBV Pol-expressed HepG2 cells compared to controls. Moreover, a series of assays-i.e. yeast two-hybrid, GST pull-down, co-immunoprecipitation, and confocal laser scanning microscopy-identified the host factor eEF1A2 to be associated with HBV Pol. Furthermore, knockdown of the eEF1A2 gene by siRNA abrogated the HBV Pol-mediated anti-apoptotic effect with apoptosis induced by endoplasmatic reticulum (ER) stress inducer thapsigargin (TG), thus suggesting that the host factor eEF1A2 is essential for HBV Pol's anti-apoptosis properties. Our findings have revealed a novel role for HBV Pol in its modulation of apoptosis through integrating with eEF1A2.