Interaction between nucleophosmin and HBV core protein increases HBV capsid assembly

Host factors are involved in Hepatitis B virus (HBV) genome replication and capsid formation during the viral life cycle. A host factor, nucleophosmin (B23), was found to bind to HBV core protein dimers, but its functional role has not been studied. This interaction promoted HBV capsid assembly and decreased the degree of capsid dissociation when subjected to denaturant treatments in vitro. In addition, inhibition of B23 reduced intracellular capsid formation resulting in a decrease of HBV production in HepG2.2.15 cells. These results provide important evidence that B23 acts on core capsid assembly via its interaction with HBV core dimers.