[Hepatitis B virus morphogenesis]

The human hepatitis B virus (HBV) is a small hepatotropic enveloped virus associated with chronic infection that can lead to cirrhosis and hepatocellular carcinoma. The HBV genome is a DNA molecule contained in an icosahedral capsid. Although HBV is not a retrovirus, the replication of its genome involves reverse transcription. Another distinctive feature of HBV is the production, in great excess over virions, of non-infectious subviral particles (SVP) consisting of membrane phospholipids and the three envelope proteins (small [S], medium [M] and large [L]). These empty non-infectious particles are highly immunogenic, and their in vitro production is at the basis of the current vaccine against hepatitis B. Despite numerous studies that lead to a better understanding of the HBV replication, little is known about the morphogenesis of the virion and its associated SVP. Recent approaches suggest that the mechanisms responsable for assembly of the virions and the SVP could be distinct.