Single-strand specificity of APOBEC3G accounts for minus-strand deamination of the HIV genome.
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.
Yu
Qin
Q
Infectious Disease Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
König
Renate
R
Pillai
Satish
S
Chiles
Kristopher
K
Kearney
Mary
M
Palmer
Sarah
S
Richman
Douglas
D
Coffin
John M
JM
Landau
Nathaniel R
NR
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
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