title: Hepatitis B virus (HBV) X gene diversity and evidence of recombination in HBV/HIV co-infected persons.
abstract: The high frequency of mutation during hepatitis B virus (HBV) infection has resulted in 8 genotypes (A-H) with varying effects on disease severity and treatment efficacy. However, analysis of intrapatient HBV diversity is limited, especially during HIV co-infection. Therefore, a preliminary study was performed to analyze HBV X gene diversity in 17 HBV/HIV co-infected individuals. Phylogenetic analysis revealed HBV genotype A in 13 individuals (76.5%) or genotype E in 1 individual (5.9%). Additionally, 3 individuals were dually infected with HBV genotypes A and G (17.6%). Overall, higher genetic distance and entropy were observed in the X region and overlapping polymerase (Pol(X)) regions when compared to the PreS, S, and overlapping polymerase (Pol(PS) and Pol(S)) regions analyzed in the same patients as part of a previous study. In addition, multiple viral variants from 2 individuals with dual HBV infection did not group with either genotype A or G by phylogenetic analysis, indicating possible recombination. SimPlot bootscan analysis confirmed recombination breakpoints within the X gene in both individuals. Recombination between HBV genotypes may represent an important evolutionary strategy that enhances overall pathogenic potential and/or alters the downstream effects of the HBV X protein.
authors.affiliation: Division of Digestive Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Martin
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Welge
authors.forename: Jason T
authors.initials: JT
authors.lastname: Blackard
mesh_terms: D000328:Adult; D056905:Chromosome Breakpoints; D003430:Cross-Sectional Studies; D004279:DNA, Viral / Q000032:analysis; D014644:Genetic Variation; D005838:Genotype; D006678:HIV / Q000254:growth & development; D015658:HIV Infections / Q000097:blood / Q000235:genetics* / Q000821:virology; D006514:Hepatitis B Surface Antigens / Q000032:analysis; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000097:blood / Q000235:genetics* / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics*; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein