Fig. 3.

Effect of combination of double-alanine Vif mutants in CBFβ-depleted cells on Vif activity. a Representative western blots showing levels of A3G, Vif, CBFβ, and tubulin in cells co-transfected with Flag-A3G, Vif variants, and CBFβ-specific siRNA or control siRNA. Lysates of virus producer cells were collected 48 h post-transfection and analyzed by western blotting. Tubulin was used as a loading control for quantitation A3G levels. Quantitation of CBFβ knockdown efficiency from two independent experiments is depicted below each lane. b Quantitation of Vif-induced A3G degradation relative to the no Vif control (control siRNA; set to 100%) from two independent experiments. c Infectivity of viruses produced in experiments shown in (a) is plotted relative to virus produced in the presence of WT Vif and control siRNA (set to 100%; not shown). Infectivity was determined by measuring luciferase activity in TZM-bl cells. Statistical significance was determined using t test; *P < 0.05