FIG. 7.

Functional analysis in osteoblastic cell lines of the Cbfa element present in the collagenase 3 promoter. MC3T3 E1, U2OS, and KHOS 321H cells were cotransfected with the collagenase 3 promoter construct p1004-luc or p1004-mutCbfa-luc fused to firefly luciferase reporter gene and with pCMV-Cbfa1 (grey bars) or pcDNA3 (white bars) as an effector plasmid. Plasmid pRL-TK was used as an internal control of transfection efficiency as described in Materials and Methods. Values represent firefly luciferase-to-Renilla luciferase ratios, normalized so that a relative activity of 1 was assigned to the basal activity of the wild-type construct in every cell line. 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).