Twin gradients in APOBEC3 edited HIV-1 DNA reflect the dynamics of lentiviral replication.
The human immunodeficiency virus (HIV) Vif protein blocks incorporation of two host cell cytidine deaminases, APOBEC3F and 3G, into the budding virion. Not surprisingly, on a vif background nascent minus strand DNA can be extensively edited leaving multiple uracil residues. Editing occurs preferentially in the context of TC (GA on the plus strand) and CC (GG) depending on the enzyme. To explore the distribution of APOBEC3F and -3G editing across the genome, a product/substrate ratio (AA + AG)/(GA + GG) was computed for a series of 30 edited genomes present in the data bases. Two highly polarized gradients were noted each with maxima just 5' to the central polypurine tract (cPPT) and LTR proximal polypurine tract (3'PPT). The gradients are in remarkable agreement with the time the minus strand DNA remains single stranded. In vitro analyses of APOBEC3G deamination of nascent cDNA spanning the two PPTs showed no pronounced dependence on the PPT RNA:DNA heteroduplex ruling out the competing hypothesis of a PPT orientation effect. The degree of hypermutation varied smoothly among genomes indicating that the number of APOBEC3 molecules packaged varied considerably.
Suspène
Rodolphe
R
Unité de Rétrovirologie Moléculaire, CNRS URA1930, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris cedex 15, France.
Rusniok
Christophe
C
Vartanian
Jean-Pierre
JP
Wain-Hobson
Simon
S
D000071478:APOBEC Deaminases; D003564:Cytidine Deaminase; D043525:Cytosine Deaminase / Q000378:metabolism*; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D007700:Kinetics; D014779:Virus Replication
D004279:DNA, Viral; D043525:Cytosine Deaminase; D000071478:APOBEC Deaminases; C502889:APOBEC3 proteins, human; D003564:Cytidine Deaminase