RESUMO
Hepatitis B virus (HBV) core protein (HBc) serves pivotal roles in the viral life cycle, particularly serving as the basic unit for capsid assembly, and is closely associated with HBV genome replication and progeny virion production. Previous studies have demonstrated that HBc has at least two functional interfaces; two HBc monomers form a homodimer via an intradimer interface, and then 90 or 120 homodimers form an icosahedral capsid via a dimerdimer interface. In the present study, the role of the HBc dimerdimer interface in HBV replication was investigated. A panel of residues located at the dimerdimer interface were identified based on the crystal structure of HBc. Native gel electrophoresis and western blotting revealed that, despite mutations in the dimerdimer interface, HBc formed a capsidlike structure, whereas mutations at amino acid residues 2339 completely disrupted capsid assembly. Using denaturing gel electrophoresis, Southern and Northern blotting, and quantitative polymerase chain reaction, it was demonstrated that none of the mutations in the dimerdimer interface supported pregenomic RNA encapsidation or DNA replication. In addition, these mutants interacted with the wild-type (WT) HBc monomer and inhibited WT genome replication and virion production in a dosedependent manner. However, the quantity of covalently closed circular DNA in the nucleus was not affected. The present study highlighted the importance of the HBc dimerdimer interface for normal capsid function and demonstrated that the HBc dimerdimer interface may be a novel antiviral target.