title: Molecular and phylogenetic analyses suggest an additional hepatitis B virus genotype "I".
abstract: A novel hepatitis B virus (HBV) strain (W29) was isolated from serum samples in the northwest of China. Phylogenetic and distance analyses indicate that this strain is grouped with a series of distinct strains discovered in Vietnam and Laos that have been proposed to be a new genotype I. TreeOrderScan and GroupScan methods were used to study the intergenotype recombination of this special group. Recombination plots and tree maps of W29 and these putative genotype I strains exhibit distinct characteristics that are unexpected in typical genotype C strains of HBV. The amino acids of P gene, S gene, X gene, and C gene of all genotypes (including subtypes) were compared, and eight unique sites were found in genotype I. In vitro and in vivo experiments were also conducted to determine phenotypic characteristics between W29 and other representative strains of different genotypes obtained from China. Secretion of HBsAg in Huh7 cells is uniformly abundant among genotypes A, B, C, and I (W29), but not genotype D. HBeAg secretion is low in genotype I (W29), whose level is close to genotype A and much lower than genotypes B, C, and D. Results from the acute hydrodynamic injection mouse model also exhibit a similar pattern. From an overview of the results, the viral markers of W29 (I1) in Huh7 cells and mice had a more similar level to genotype A than genotype C, although the latter was closer to W29 in distance analysis. All evidence suggests that W29, together with other related strains found in Vietnam and Laos, should be classified into a new genotype.
authors.affiliation: National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, China.
authors.forename: Hai
authors.initials: H
authors.lastname: Yu
authors.forename: Quan
authors.initials: Q
authors.lastname: Yuan
authors.forename: Sheng-Xiang
authors.initials: SX
authors.lastname: Ge
authors.forename: Hurng-Yi
authors.initials: HY
authors.lastname: Wang
authors.forename: Ya-Li
authors.initials: YL
authors.lastname: Zhang
authors.forename: Qing-Rui
authors.initials: QR
authors.lastname: Chen
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Pei-Jer
authors.initials: PJ
authors.lastname: Chen
authors.forename: Ning-Shao
authors.initials: NS
authors.lastname: Xia
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D045744:Cell Line, Tumor; D002681:China; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics*; D005838:Genotype; D006509:Hepatitis B / Q000097:blood / Q000821:virology*; D006512:Hepatitis B Core Antigens / Q000097:blood / Q000378:metabolism; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000378:metabolism; D006513:Hepatitis B e Antigens / Q000097:blood / Q000378:metabolism; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics* / Q000276:immunology; D006801:Humans; D007812:Laos; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014744:Vietnam
chemical_list: D004279:DNA, Viral; D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens; D006513:Hepatitis B e Antigens