title: Single-strand specificity of APOBEC3G accounts for minus-strand deamination of the HIV genome.
abstract: HIV-1 deleted for the vif accessory gene encapsidates the cellular cytidine deaminase APOBEC3G. Upon infection, the encapsidated APOBEC3G induces G-->A mutations in the viral reverse transcripts. The G-->A mutations result either from C-->U deamination of the minus strand or deamination of both strands followed by repair of the plus strand. We report here that minus-strand deamination occurred over the length of the virus genome, preferentially at CCCA sequences, with a graded frequency in the 5'-->3' direction. APOBEC3G induced previously undetected C-->T mutations in the 5' U3 and the primer-binding site, both of which become transiently single-stranded during reverse transcription. In vitro, APOBEC3G bound and deaminated single-stranded DNA (ssDNA) but not double-stranded DNA (dsDNA) or DNA-RNA hybrids. We propose that the requirement for ssDNA accounts for the minus-strand mutations, the 5'-->3' graded frequency of deamination and the rare C-->T mutations.
authors.affiliation: Infectious Disease Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
authors.forename: Qin
authors.initials: Q
authors.lastname: Yu
authors.forename: Renate
authors.initials: R
authors.lastname: König
authors.forename: Satish
authors.initials: S
authors.lastname: Pillai
authors.forename: Kristopher
authors.initials: K
authors.lastname: Chiles
authors.forename: Mary
authors.initials: M
authors.lastname: Kearney
authors.forename: Sarah
authors.initials: S
authors.lastname: Palmer
authors.forename: Douglas
authors.initials: D
authors.lastname: Richman
authors.forename: John M
authors.initials: JM
authors.lastname: Coffin
authors.forename: Nathaniel R
authors.initials: NR
authors.lastname: Landau
mesh_terms: D000071480:APOBEC-3G Deaminase; D003564:Cytidine Deaminase; D016679:Genome, Viral; D006678:HIV / Q000235:genetics*; D009700:Nucleoside Deaminases; D011506:Proteins / Q000378:metabolism* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D012097:Repressor Proteins
chemical_list: D011506:Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D012097:Repressor Proteins; D009700:Nucleoside Deaminases; D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase