Figure 4

Effect of increasing amounts of Rev M10-encoding plasmid (pCI-Rev M10) on titer of vector stocks produced with an HIV-1 packaging system containing either HIV-1 or SIV RRE. The HIV-1 RRE-based packaging system (HIV-1 RRE system) consisted of the packaging plasmid pGP/HIV-1 350 RRE and the gene transfer vector pN-EF1α-EGFP/HIV-1 RRE. The SIV RRE-based packaging system (SIV RRE system) consisted of the packaging plasmid pGP/SIV 1045 RRE and the gene transfer vector pN-EF1α-EGFP/SIV RRE. For production of virus stocks with the SIV RRE-based packaging system either HIV-1 Rev (pCI-HIV Rev) or SIV Rev (pCI-SIV Rev) expression construct was used, as indicated. All transfections also received a VSV-G envelope expression construct (pMD.G) and a HIV-1 Tat (pCMVtat) expression construct. The titers of the vector stocks were determined as described in Materials and Methods. The % of GFP + cells in the absence of pCI-Rev M10 (0 μg) was considered as 100% (Y-axis) for a given packaging system to which other titers obtained at each amount of pCI-Rev M10 were normalized. Increasing amounts of pCI-Rev M10 are depicted on the X-axis. For each transfection, the indicated amount of pCI-Neo was used as a 'filler', to keep the total amount of DNA added at 1.0 μg. The results shown are representative of two independent experiments.