ABSTRACT
Hepatitis B virus (HBV) is a major world health problem due to the high percentage of chronic HBV carriers, worldwide now approximately 200 million people, and the association of HBV with hepatocellular carcinoma, one of the most common human cancers. This chapter focuses on the processes involved in HBV replication via an RNA intermediate and to make a brief comparison of this replication strategy with those employed by other retroviruses and retrotransposons. The fact that some HBV-infected individuals produce antibodies against X-sequences points to the protein being expressed in vivo. In the nucleus of infected liver cells, free, covalently closed, circular, supercoiled, viral DNA can be detected, and evidence points to this being produced shortly after infection. In the case of hepatitis B virus, several gene products are coded for by a single ORF, and this is achieved by regulating gene expression both at the transcriptional and translational level.
