Figure 3. HIV-1 accessory proteins Vpr and Vif are necessary for HIV-1-induced suppression of cellular translation.

(A) CEMx174 cells infected with HIV-1, VprX, ΔVifVprX (ΔVV) or mock-infected were incubated with or without nocodazole (Noc) and then metabolically labeled with [³⁵S]-cysteine/methionine for one hour and proteins were precipitated with TCA. [³⁵S]-cysteine/methionine incorporation was measured by scintillation in three independent experiments and is presented with standard deviation. Asterisk indicates the significant reduction (p<0.05) as summarized in text for all of the infections except ΔVifVprX (p = 0.8062). Nocadozole treatment significantly reduced the de novo protein synthesis in all of the infections. Propidium iodide staining intensity and ModFit analysis demonstrates the number and percentage of cells in the G1 or G2/M phase of the cell cycle. Percentages are summarized below the plots. (B) Comparison of de novo HIV-1 Gag and cellular Actin protein production with or without nocadozole treatment. CEMx174 cells were metabolically labeled with [³⁵S]-cysteine/methionine for one hour, followed by immunoprecipitation with antisera to Gag and Actin. The immunoprecipitated proteins were resolved by SDS-PAGE and phosphorimager analysis is presented. Positions of Actin and Gag p55, p37 and p24 are indicated.