APOBEC3 versus Retroviruses, Immunity versus Invasion: Clash of the Titans

Figure 1

A3G can exert multiple antiviral effects against HIV-1 infection. Virion-packaged A3G restricts HIV-1Δvif replication via cytidine deaminase-mediated hypermutation as well as interfering with efficient reverse transcription. Additionally, the introduction of the uridines into the minus-strand DNA during reverse transcription triggers the DNA damage response (DDR). This induction of DDR involves other proteins, including the host protein, UNG, and the HIV-1 Vpr protein. Among other downstream effects, the DDR stimulates the transcriptional synthesis of NKG2D ligands. The subsequent expression of these proteins on the surface of the HIV-infected cell sensitizes it to NK cell lysis. It should also be noted that A3G expression within the target cell (designated as dotted symbols to distinguish it from the virion-packaged A3G). Also critically participates in the DDR activation.