Cloning and Sequence Analysis of Human Hepatitis B Virus preS Gene Variants from Hangzhou an d Lanzhou in China
Abstract: PreS gene fragments were inserted into pBluescript SK after being amplified by PCR from HBV DNA,which was extracted from HBsAg-positive sera(Hangzhou and Lanzhou samples)and the cloned genes were sequenced.The complate nucleotide sequences of the cloned preS genes(preS-HZ and preS-LZ,GenBank accession numbers:Af325674 and AF325675 respectively) were 522bp long,encoding 174aa.The identity of preS-HZ with published preS gene Shagnhai isolate(adr subtype:Gan,et al.,1986),Beijing isolate (adr subtype:Qi,et al.,1989),Japan isolate(adr subtype:Ono,et al.,1983),adw subtype(Valenzuela,et al.,1980),ayw subtype (Galibert,et al.,1979)was respectively 96.7%,96.2%,97.3%,88.7%,84.1% for nucleotide sequence and 96.0%,94.9%,97.1%,85.1%,85.4% for amino acid sequence;correspondingly,preS-LZ was respectively 96.4%,96.2%,96.9%,88.7%,83.7 for nucleotide sequence and 94.9%,94.9%,96.0%,85.1%,84.1% for amino acid sequence.Only two nucleotide substitutions(resulting in two amino acid changes) were observed between preS-HZ and preS-LZ