Patama Monkongdee. Cloning and sequencing of hepatitis B virus genome adr subtype isolated in Thailand. Master's Degree(Microbiology). Mahidol University. Mahidol University Library and Knowledge Center. : Mahidol University, 1996.
Cloning and sequencing of hepatitis B virus genome adr subtype isolated in Thailand
Abstract:
Hepatitis B virus (HBV) DNA from Dane particle of adr subtype isolated from blood specimens donated to the Thai Red Cross was cloned into BamHI site of plasmid pBS (+SK). The recombinant plasmid was transformed into E. coli XL- 1B. Restriction endonuclease analysis showed that the cloned HBV did not have BssH1I, EcoRI, NotI, PvuII and SacI sites but has vIpaI, BamHI, Bg/II, HpaI, KpnI, SacII, SphI, XbaI and XhoI sites, which some positions are different from others adr subtypes. Its complete nucleotide sequence was determined. The 3,215 bp sequences show the presence of 4 open reading frames (ORF) for PreS+HBsAg (174+226 amino acids), P (843 amino acids), HBcAg (212 amino acids) and X (154 amino acids). The gene locus organization was not different from those of the other adr clones so far reported. It was found that all of the direct repeat of the undecanucleotide sequence (DR1) near the 5 ends of the short (S) and long (L) strands of HBV DNA and the two small direct repeat sequences (DR2 and DR3) between both 5 ends were characteristic structures of HBV. The deduced amino acid sequences of HBsAg was analyzed in detail. The 9 amino acids of antigenic determinant a, 139CTKPSDGNC- 147, of this clone were found to be conserved. Furthermore, Cys- 124, Cys- 147 and Pro- 142 required for full antigenecity were also observed. The protein possesed Lys-122 (d) and Arg-160 (r) which were charac-teristic of adr subtype. Based on the deduced amino acid comparison in HBsAg, the genotype of cloned HBV was classified as group C. The presence of Val-177 and Pro-178 in HL,sAg indicated that the clone HBV had q subtype determinant. Furthermore, the amino acid sequence which was proposed to be the immunodeterminant of Pre-S2 region, at position 1 3 1 LLDPRVRGLYFPAG-144, and position 162-SSIFSRT-168, were found. Regarding to the conservation of amino acids defined in HBsAg and Pre-S region and some amino acids which are different from others adr subtype, the clone HBV adr subtype in this study would be suitable to use as a source of HBsAg for the production of recombinant vaccine for Thai population in the future.