Interactions between the surface and capsid proteins of the hepatitis B virus (HBV) are critical for the assembly of
virus particles. In this study, we developed a cell-based method to visualize the interactions between the capsid and
surface proteins of HBV. Capsid-GFP, a capsid protein fused to a green fluorescence protein (GFP), forms
nucleocapsid-like structures in the cytoplasm of mammalian cells. It relocates to the plasma membranes in cells
expressing PH-PreS, a fusion protein consisting of the PreS region of the HBV surface protein and the PH domain
of PLC-γ. Membrane localization of the capsid-GFP in these cells is prevented by an inhibitory peptide that blocks
the interaction between the capsid and surface proteins. This dynamic localization of capsid-GFP is applicable for
screening compounds that may potentially inhibit or prevent the assembly process of HBV particles.