Binding of HMG Proteins to the 5'Flanking Sequence of Human β-Globin Gene

Our previous studies have identified that there are at least three regulatory regions (two negative regions and one positive region) in the 5’-flanking sequence of human β-globin gene (-610 to +1 bp). The binding of HMG proteins to both negative regulatory regions was examined by the gel mobility shift and DNase I protection assays.In gel mobility shift assay,we observed that HMG proteins 1 and 2 could bind to both negative regulatory regions (NCR1 and NCR2).Using the gel shift competition assay,we identified that the binding proteins between the two regions are different from each other.DNase I protection analysis shows that HMG proteins 1 and 2 only bind to one site (between-560 and-533 bp) in NCR1.However,two protected regions can be detected in NCR2, one between-272 and-252 bp relative to the cap site, the other between-306 and-329 bp.We also observed that HMG proteins 14 and 17 could not bind to both negative regions, so it seems that HMG proteins 1 and 2 may play an important role in the regulati