FIG. 5.

Transactivation of HIV-1 clade B LTR by recombinant Tat proteins. For luciferase assays, Jurkat T cells were transiently transfected with the LTR B-pGL3 reporter construct (80 ng) in the absence or presence of an expression plasmid encoding Flag-tagged Tat BC, EC, BE, or EB (50 ng). Relative luciferase activities were determined as described in the legend to Fig. 1. For an analysis of protein expression, Cos7 cells were transfected with 5 μg of a plasmid encoding the Flag-tagged Tat B, C, E, BC, EC, BE, or EB protein. WCE (50 μg) were resolved by SDS-PAGE and immunoblotted by using anti-Flag and anti-actin antibodies.