Deletion analysis identified a Pit-1-responsive region in the human MMP-1 and MMP-13 promoter. (A) The MMP-1 promoter fragments that fused to the pGL2-Basic vector (pGL2B) were transfected into MCF-7 cells and then transfected with the pRc/RSV or the pRSV-hPit-1 vector. Normalized relative luciferase units (RLU) were calculated as the ratio of luciferase activity in the pRSV-hPit-1-transfected cells to that in the corresponding control (pRc/RSV-transfected) cells. (B) The MMP-13 promoter fragments that fused to the pGL2Basic vector (pGL2B) were transfected as indicated in A. Data are expressed as indicated in A. MMP-1, matrix metalloproteinase-1; MMP-13, matrix metalloproteinase-13; Pit-1, POU class 1 homeobox 1.