Figure 2. Loss of IFNβ mediated repression of MMP-9 promoter when the binding of AP-1 to the proximal site is abrogated.

HT1080 cells were transfected with −154 MMP-9 promoter deletion construct containing a point mutation in the proximal AP-1 site, which renders the binding site non-functional. Cells were prepared as described previously and were treated with 100 U/mL IFNβ for 18 hours prior to preparation of cell extracts. Cell extracts were assayed for firefly luciferase activities, and normalized by protein concentration to account for any cell concentration differences between samples. Black bars: untreated values considered as 1 for each construct, white bars: IFNβ treated. The experiment was repeated three times and the error bars represent standard deviation calculated from three separate experiments. The P-values were calculated using statistical analysis software. As indicated above the bars, * symbol indicates a P value of 1.8×10⁻⁴ (significant difference) and the symbol # indicates a P value of 0.092 (no significant difference), with significant values being <0.01.