FIG. 6.

Increasing the strength of or removing the Rev AUG modulates Vpu expression. (A) Mutations in the env2 cDNA constructs that either strengthened the Rev AUG codon (underlined; RevK) or removed it (Rev⁻). (B and C) HeLa cells were transfected with the env cDNA constructs, pCMVTat2X, pEGFP, and pDM128 without (B) or with (C) pLTRrev1. Rev activity was measured by CAT assay. Env and Vpu were detected by immunoblotting followed by densitometry analysis, and the percentage of expression relative to the expression of the env1 R38 mutant (E1R38; set at 100%) is graphed. wt, wild type; Mk, mock (no env or pLTRrev1); E1 and E2, pDRenv1 and pDRenv2; E2K, env2 cDNA construct expressing RevK mutation; E2R38, env2 cDNA construct expressing R38 mutation; E2KR38, env2 cDNA construct expressing RevK and R38 mutations; E2R−, env2 cDNA construct expressing Rev⁻ mutation.