Molecular cloning and characterization of the cDNA coding for hepatitis B virus surface antigen

Hepatitis B virus surface antigen (HBsAg) mRNA has been enriched from a hepatoma cell line (PLC/PRF/5) by specific polysome immunoprecipitation and used for cDNA cloning. A HBsAg cDNA clone was identified by in situ hybridization with a cloned viral probe. It was characterized by restriction endonuclease mapping and DNA sequence analysis. Molecular hybridization of PLC/PRF/5 cellular DNA and RNA to [32P]-labeled HBsAg cDNA revealed the integration of at least six copies of the hepatitis B virus (HBV) DNA into the host genome and expression of three DNA species containing HBsAg-specific sequences. The possible role of HBV in the oncogenesis of primary hepatocellular carcinoma is discussed.