Figure 4. Tat-Mediated RNAi Suppression Is Essential for HIV-rtTA Virus Production.

(A) TZM-bl cells containing a Tat-responsive firefly luciferase reporter gene under control of the HIV-1-LTR were transfected with pBluescript (−), Tat^wt, Tat^F32A, or Tat^Y26A. Luciferase expression was determined 2 d post transfection.

(B) Transfection of HEK293T cells with the luciferase reporter expression plasmid (Luc), the vector expressing an shRNA against luciferase (Luc + shLuc), and expression plasmids for Tat^wt , Tat^F32A, or Tat^Y26A. Luciferase expression was determined 2 d post transfection.

(C) Virus production 2 d post transfection in HEK293T cells transfected with HIV-rtTA-Tat^fs and expression plasmids for Tat^wt, Tat^F32A, or Tat^Y26A.