Characterization of restriction endonuclease maps of hepatitis B viral DNAs

The HBV DNA isolated from Dane particles of 9 patients' plasma was cloned into the EcoRI or BamHI site of the pUC8 plasmids. Two plasmids with full length HBV DNA and four plasmids containing the HBV surface antigen gene were obtained. Based on our cloned HBV DNA and a comparison with 7 complete sequences and 5 restriction endonuclease patterns of HBV DNA published by others, we can recognize common restriction sites shared by different subtypes (adw, adr, ayw, and adyw): (1) a HincII site in the S gene, (2) a BamHI site in the X region, and (3) two BglII sites in the C gene. In addition adw has specific sites for HincII, BamHI, and PstI in the pre-S region. A unique XhoI site is present in the pre-S region in all subtypes except for adw.