A clone of hepatitis B virus (subtype adr) DNA with a new HindIII site

We have cloned the HBV genome subtype adr through its HindIII site into plasmid pBR322. Twelve recombinant plasmids each with an insert of the HBV genome were obtained. The restriction map of one of the recombinants, plasmid pADR-H1, was analyzed. The location of the sites for BamHI, BglI, BglII, SstII, XbaI and XhoI in pADR-H1 were found to be the same as that in pADR-1, but the HindIII site of pADR-H1 is distinctly different from that of pADR-1. The BamHI-HindIII fragment is 316 bp long in the genome of pADR-1. However, it is only 82 bp in pADR-H1. No deletion of sequence between BamHI and HindIII sites has been found in the HBV genome of pADR-H1. The sequencing data around the HindIII site of pADR-H1 in both pADR-H1 and pADR-1 showed that there is a stretch of AAGTTT in pADR-1 compared to an AAGCTT in pADR-H1. In addition, other differences were found. There are three sites for AvaI, four for HincII, one for HpaI and none for SphI in the genome of pADR-H1 compared to four sites for AvaI, three for HincII, one for SphI and none for HpaI in pADR-1. The biological significance of base pair mutation in HBV DNA and the possibility of the existence of HindIII site in the genome of subtypes ayw and adw were discussed.