FIG. 2.

Activation of HIV-1 gene expression by Tat. HeLa cells were cotransfected with the reporter constructs HIV-1 LTR-CAT and pCH110 (β-Gal) together with plasmids (pDex) that expressed either the β-globin gene (bar 1), the wild type tat gene (bar 2), or the mutated tat genes corresponding to [E2G, D5G, E9G] (bar 3), P3L (bar 4), P[6, 10]L (bar 5), P[10, 14]L (bar 6), C27S (bar 7), K41A (bar 8), and K/R[50-57]G (bar 9). The cells were harvested at 48 h posttransfection, and equal amounts of protein were normalized to β-Gal activity and assayed for CAT protein by ELISA. The transfections were performed three times with the standard deviations indicated.