Figure 3.

Overexpression of a non-DNA-tethered activating region does not enhance transcriptional activation elicited by nonclassical activators. All the Gal4 derivatives were expressed from the SV40 enhancer-promoter, and the VP16 activating region (residues 411–490) was expressed from the CMV promoter. DNA (0.5 μg) encoding each indicated Gal4 derivative (except for that encoding Gal4 + VP16, in which case 0.2 μg was used) was cotransfected with (black bars) or without (white bars) increasing amounts (0.25, 0.5, and 1 μg) of DNA encoding the VP16 activation domain. The reporter template (0.5 μg) was used and, as an internal control, 0.2 μg of a plasmid encoding lacZ expressed from the CMV enhancer-promoter. The lipofectamine method was used for transfecting HeLa cells with the indicated plasmids, and results of luciferase assays are shown.