HIV-1-associated uracil DNA glycosylase activity controls dUTP misincorporation in viral DNA and is essential to the HIV-1 life cycle.
Uracilation of DNA represents a constant threat to the survival of many organisms including viruses. Uracil may appear in DNA either by cytosine deamination or by misincorporation of dUTP. The HIV-1-encoded Vif protein controls cytosine deamination by preventing the incorporation of host-derived APOBEC3G cytidine deaminase into viral particles. Here, we show that the host-derived uracil DNA glycosylase UNG2 enzyme, which is recruited into viral particles by the HIV-1-encoded integrase domain, is essential to the viral life cycle. We demonstrate that virion-associated UNG2 catalytic activity can be replaced by the packaging of heterologous dUTPase into virion, indicating that UNG2 acts to counteract dUTP misincorporation in the viral genome. Therefore, HIV-1 prevents incorporation of dUTP in viral cDNA by UNG2-mediated uracil excision followed by a dNTP-dependent, reverse transcriptase-mediated endonucleolytic cleavage and finally by strand-displacement polymerization. Our findings indicate that pharmacologic strategies aimed toward blocking UNG2 packaging should be explored as potential HIV/AIDS therapeutics.
Priet
Stéphane
S
Pathogénie des Infections à Lentivirus, INSERM U372, Université de la Méditerranée, 163 Avenue de Luminy, BP 178, 13276 Marseille Cedex 9, France.
Gros
Nathalie
N
Navarro
Jean-Marc
JM
Boretto
Joëlle
J
Canard
Bruno
B
Quérat
Gilles
G
Sire
Joséphine
J
D001483:Base Sequence; D003596:Cytosine / Q000378:metabolism; D045647:DNA Glycosylases / Q000235:genetics / Q000378:metabolism*; D004279:DNA, Viral; D003641:Deamination; D003856:Deoxyuracil Nucleotides / Q000235:genetics*; D016346:Gene Products, vif / Q000378:metabolism; D016679:Genome, Viral; D015658:HIV Infections / Q000201:enzymology* / Q000821:virology; D054303:HIV Reverse Transcriptase / Q000378:metabolism; D015497:HIV-1 / Q000201:enzymology* / Q000254:growth & development; D006801:Humans; D008969:Molecular Sequence Data; D011755:Pyrophosphatases / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D051981:Uracil-DNA Glycosidase; D014771:Virion / Q000201:enzymology*; D014779:Virus Replication; D054320:vif Gene Products, Human Immunodeficiency Virus
D004279:DNA, Viral; D003856:Deoxyuracil Nucleotides; D016346:Gene Products, vif; D054320:vif Gene Products, Human Immunodeficiency Virus; C027078:deoxyuridine triphosphate; D003596:Cytosine; D054303:HIV Reverse Transcriptase; D045647:DNA Glycosylases; D051981:Uracil-DNA Glycosidase; D011755:Pyrophosphatases; C020020:dUTP pyrophosphatase