简介：HBV is a hepatotropic small DNA virus. The infectious virion circulates as a 42-nm Dane particle that comprises a nucleocapsid surrounded by a lipid envelope. The HBV genome is a 3.2-kb circular, partially double-stranded DNA molecule with four overlapping open reading frames (ORFs) named PC-C, PS-S, P, and X ORFs. Although HBV is a DNA virus, replication of the viral DNA occurs via a RNA intermediate. Upon entry into the cell, the virus uncoats, and the relaxed circular genome is transported to the nucleus.