UNG and HIV-1 infection: 1). The Q3R and R77Q mutants were shown to be impaired in their proapoptotic activity and to be associated with long-term non-progressive HIV-1 infection [39,40] while the R90K mutant failed to cause the G2/M cell arrest [41]. Moreover, the W54G mutant was shown to be critical for the interaction with cellular UNG (Uracil DNA glycosilase) and its virion incorporation [41].