Scheme of deletions and mutations introduced into the murine Hamp1 promoter. Murine Hamp1 and Hamp2 and human HAMP were aligned, and conserved transcriptional motifs were identified. Deletions in the proximal Hamp1 promoter region (A) and deletions in the distal −1.6 to −1.8 kb promoter region (B) are indicated. After narrowing to the BMP-RE2/bZIP/COUP/HNF4α region, further deletions and mutations were introduced to identify the critical motif (C). The 6-bp BMP-RE deletion (2-sided arrow), the 7-bp mutation of the HNF4α/COUP site (HNF4/COUP mut; underlined), the single nucleotide mutation to reflect the sequence in Hamp2 (Hamp2 mut), and the 4-bp mutation of the bZIP site (bZIP mut; double-underlined line) are shown.