Figure 6.

Functional mapping of the region responsible for the Sp1–GKLF-mediated synergistic activation of rat LAMC1 promoter in SL2 cells. The Drosophila SL2 cells were transiently co-transfected with a series of LAMC1 promoter deletion constructs in combination with 50 ng of either pPac-O (pPac), pPac-GKLF (GKLF), pPac-Sp1 (Sp1) or both expression (GKLF&Sp1) plasmids. Forty-eight hours following transfections, cells were harvested and both firefly and renilla luciferase activities in the cell lysates were measured. Activities of the promoter constructs were calculated as ratios of firefly to renilla luciferase activity (mean of n = 4). The numbers shown for each construct represent values that were normalized by dividing each firefly luciferase activity by the renilla luciferase activity measured in pPac alone. Synergism was calculated as the activity obtained when cells were co-transfected with both Sp1 and GKLF divided by the sum of the activities measured when Sp1 and GKLF were expressed alone, GKLF&Sp1/GKLF + Sp1, where a ratio >1.0 reflects synergistic activation.