FIG. 3.

Analysis of the role played by the AP-1 element in collagenase 3 promoter activation by Cbfa1 in HeLa cells. The complete collagenase 3 promoter construct or a construct containing eight copies of the Cbfa element linked to the p83-luc promoter and containing a double mutation in the AP-1 element (p1004-mutAP1-luc and Cbfa₈-p83-mutAP1-luc) was transfected in HeLa cells, as described in the legend to Fig. 2 and assayed for luciferase (luc) activity. The corresponding wild-type constructs were also transfected in parallel experiments. Data are expressed as means ± standard errors of at least three independent experiments. Asterisks indicate significant differences from the control (∗∗, P < 0.01; ∗∗∗, P < 0.001).