The effect of various Hamp1 promoter deletions on the SMAD1, HJV, BMP2, and BMP9 induced response. Firefly reporter constructs driven by the murine Hamp1 promoter were used, 2.5 kb Hamp1 WT was the positive full-length promoter control, 260 bp Hamp1 represented the minimal promoter, and pGL3 represented the negative promoterless control. Constructs containing deletions in the proximal region of Hamp1 promoter (STAT del and 140-260 bp del) as well as deletions in the distal −1.6 to −1.8 kb region (all others) were transfected into HepG2 cells and either cotransfected with SMAD1 (A) and hemojuvelin (B) or treated with 10 ng/mL BMP4 (C) and BMP9 (D) for 12 to 16 hours. Firefly/Renilla ratio of nontreated 2.5-kb Hamp1 WT construct was set as 1.00. Mean and SEM of the relative firefly/Renilla ratios of at least 3 independent experiments are shown.