FIG. 1.

Transcriptional activity of Vpr and its mutant variants. (A) Structural organization of wild-type Vpr depicting the areas representing helical domains I and II and the leucine-rich domain. (B) Transcriptional activity of wild-type (wt) and mutant (R73S and R73A) Vpr upon the HIV-1 LTR promoter. The human astroglial cell line T98G was transfected with 1.0 μg of the reporter LTR-luciferase plasmid (LTR-Luc) alone or combined with 2.5 μg of the Vpr expression plasmids by calcium phosphate precipitation (11). All Vpr expression plasmids were created in pcDNA3 background plasmids, and empty pCDNA3 was added in all transfection mixtures in order to normalize the amounts of the DNA in each reaction. Luciferase activity was determined 48 h after transfection. The values shown on the top of each bar represent the fold activation over the basal HIV-1 LTR promoter arbitrarily set at 1. The data represent the mean value of at least three separate transfection experiments.