Interaction between nucleophosmin and HBV core protein increases HBV capsid assembly

Abstract

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 be bound to HBV core protein dimers, but its functional role of interaction has remained to be elucidated. In this study, we used in sillico modeling to predict the sites of physical interaction between B23 and core protein dimers and used mutagenesis to confirm the prediction. The binding of core protein and B23 promoted HBV capsid assembly and protected the degree of capsid dissociation when subjected to detergent treatments in vitro. In addition, chemical inhibition of B23 reduced intracellular capsid formation resulting of reduced HBV production in HepG2.2.15 cells. These results provided important evidence that the oligomeric form of B23 acts on core capsid assembly.