Figure 2

Physical interaction of HMGA1 with the IGFBP-3 promoter. In the upper panel, a schematic representation of the IGFBP-3 gene is shown with HMGA1, Sp1, and C/EBPβ DNA binding sites. h1 and h2 are IGFBP-3 DNA sequences that were used as probes. In the lower panel, EMSAs were performed by using the h1 and h2 DNA probes in the absence (-) and presence (+) of pure HMGA1 (5 ng). The non-AT-rich sequence was used as a negative control probe. C/EBPβ, CAAT-enhancer binding protein β; EMSA, electrophoretic mobility shift assay; HMGA1, high-mobility group A1; IGFBP-3, insulin-like growth factor binding protein 3.