The spliced variant of hepatitis B virus protein, HBSP, interacts with Bcl-2/Bcl-xl in vitro and induces apoptosis in HepG2 cells

We have recently reported that the naturally occurring spliced variant of Hepatitis B virus protein, HBSP, displayed proapoptotic activity through its BH3 domain. To investigate whether the BH3 domain in HBSP interacted with Bcl-2 family of proteins, HBSP and Bcl-2 family of proteins were cloned and expressed in our mammalian two-hybrid system. Interaction assays were carried out in HepG2 cells and measured by the activity of the reporter gene product luciferase. Our results indicated that HBSP interacted with Bcl-2/Bcl-xl in vitro and induced apoptosis in HepG2 cells.