title: Frequency of spontaneous mutations in an avian hepadnavirus infection.
abstract: In this study, we measured the frequency of revertants of a cytopathic strain of the duck hepatitis B virus that bears a single nucleotide substitution in the pre-S envelope protein open reading frame, resulting in the amino acid substitution G133E. Cytopathic virus mixed with known amounts of a genetically marked wild-type virus was injected into ducklings. Virus outgrowth was accompanied by a coselection of wild-type and spontaneous revertants during recovery of the ducklings from the acute liver injury caused by death of the G133E-infected cells. The frequency of individual revertants in the selected noncytopathic virus population was estimated by determining the ratio of each revertant to the wild-type virus. Spontaneous revertants were found to be present at frequencies of 1 x 10(-5) to 6 x 10(-5) per G133E genome inoculated. A mathematical model was used to estimate that the mutation rate was 0.8 x 10(-5) to 4.5 x 10(-5) per nucleotide per generation.
authors.affiliation: Department of Molecular Genetics and Microbiology, The University of New Mexico School of Medicine, Albuquerque, New Mexico 87131, USA.
authors.forename: I
authors.initials: I
authors.lastname: Pult
authors.forename: N
authors.initials: N
authors.lastname: Abbott
authors.forename: Y Y
authors.initials: YY
authors.lastname: Zhang
authors.forename: J
authors.initials: J
authors.lastname: Summers
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D003001:Cloning, Molecular; D004195:Disease Models, Animal; D004372:Ducks; D016679:Genome, Viral; D005838:Genotype; D018347:Hepadnaviridae Infections / Q000821:virology*; D015611:Hepatitis B Virus, Duck / Q000737:chemistry / Q000235:genetics*; D008099:Liver / Q000821:virology; D008962:Models, Theoretical; D009154:Mutation; D011995:Recombination, Genetic; D013997:Time Factors; D014759:Viral Envelope Proteins / Q000235:genetics; D014766:Viremia
chemical_list: C077433:Pre-S protein, Duck hepatitis B virus; D014759:Viral Envelope Proteins