Role of SP1-binding elements in MMP-2 transcriptional activity. (a) The diagrams of the reporter constructs of full-length or various deletion mutants of MMP-2 promoter (D1–D7) are depicted on the left. The solid lines are the regions cloned upstream of the luciferase gene in the pGL3 luciferase reporter vector. The luciferase activity of cell extracts was analyzed by luciferase reporter assay. Data are presented as the mean of triplicate replications. S.D. is indicated by error bars. ** versus HEK293/NNMT cells transfected with full-length MMP-2 promoter. (b) Effects of site-specific mutation of the two putative SP1-binding sites on MMP-2 promoter activity were examined by luciferase reporter assay. Data are presented as the mean of triplicate replications. S.D. is indicated by error bars. ** versus HEK293/NNMT cells transfected with wild-type D3 construct.
