In the absence of HIV-Vif, human A3G, one member of the APOBEC3 (A3) enzymes, is the natural most potent anti-HIV inhibitor . During experimental HIV infections in the absence of Vif, human A3G binds RNAs in the cytoplasm of the host cells and is encapsidated into the new virions . In the HIV subsequent infection-replication cycle, the encapsidated A3G randomly induces dC lethal deaminations to dU (deoxyCytosine to deoxyUracil) during the reverse transcription of the HIV genome, reducing their replication and infection.