Fig. 3.

Mutation of the Vif PPLP motif affects the infectivity of virus produced in A3G expressing cells. HEK293-APOBEC3G-HA cells were co-transfected with proviral plasmid pNL4-3(Δvif) and plasmids expressing either wild-type Vif (pHVif) or PPL mutant Vif [pHVif(A ¹⁶¹ AA)]. Cells were also co-transfected with proviral plasmid pNL4-3 or pNL4-3(Δvif) plus empty vector, pcDNA3.1(−). (A) Viral infectivity of culture supernatants 48 hours post-transfection was determined using the TZM-bl indicator cell line as described in Materials and methods. Shown are Relative Light Units (RLU) plus standard deviation of triplicate determinations normalized to the viral p24 levels measured in culture supernatants. (B) Analysis of A3G and Vif levels in viral and cell lysates by Western blotting (WB). The antibodies used to detect A3G, Vif, p24 and β-actin are described in Materials and methods.