title: Characteristics of hepatitis B virus isolates of genotype G and their phylogenetic differences from the other six genotypes (A through F).
abstract: Eight hepatitis B virus (HBV) isolates of genotype G were recovered from patients and sequenced over the entire genome. Six of them had a genomic length of 3,248 bp and two had genomic lengths of 3,239 bp (USG15) and 3,113 bp (USG18) due to deletions. The 10 HBV/G isolates, including the 8 sequenced isolates as well as the original isolate (AF160501) and another isolate (B1-89), had a close sequence homology of 99.3 to 99.8% among themselves (excluding USG18 with a long deletion) but of <88.7% to any of the 68 HBV isolates of the other six genotypes with the full-length sequence known. The eight HBV/G isolates possessed an insertion of 36 bp in the core gene and two stop codons in the precore region, as did the AF160501 and B1-89 isolates. The 10 HBV/G isolates clustered on a branch separate from those bearing the other six genotypes (A through F [A-F]) in the phylogenetic tree constructed from full-length sequences of 78 HBV isolates as well as in those constructed from the core, polymerase, X, and envelope genes. Despite two stop codons in the precore region that prohibited the translation of the HBV e antigen (HBeAg), all of the eight patients with HBV/G infection possessed the HBeAg in serum. By restriction fragment length polymorphism of the surface gene, all of the eight patients were found to be coinfected with HBV of genotype A (HBV/A), which would be responsible for the expression of HBeAg in them. It is worthy of examination to determine how coinfection occurs and whether HBV/G needs HBV/A for replication.
authors.affiliation: Department of Internal Medicine and Molecular Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kato
authors.forename: Etsuro
authors.initials: E
authors.lastname: Orito
authors.forename: Robert G
authors.initials: RG
authors.lastname: Gish
authors.forename: Fuminaka
authors.initials: F
authors.lastname: Sugauchi
authors.forename: Seiji
authors.initials: S
authors.lastname: Suzuki
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Ueda
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Miyakawa
authors.forename: Masashi
authors.initials: M
authors.lastname: Mizokami
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D004279:DNA, Viral / Q000235:genetics; D016679:Genome, Viral; D005838:Genotype; D006515:Hepatitis B virus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D019694:Hepatitis B, Chronic / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010802:Phylogeny; D011498:Protein Precursors / Q000235:genetics; D017422:Sequence Analysis, DNA; D014758:Viral Core Proteins / Q000235:genetics
chemical_list: D004279:DNA, Viral; D011498:Protein Precursors; D014758:Viral Core Proteins