DNA bend sites in the promoter region of the human estrogen receptor α gene

Abstract

DNA bend sites in the promoter region of the human estrogen receptor a gene were determined by the circular permutation assay. Among a total of five sites (ERB-4 to -1, and ERB+1) mapped in the 3 kb region, three matched with the positions of the predicted periodicity while the other two did not. Most of the sites were accompanied by the short poly (dA) -poly (dT) tracts including the potential bend core sequence A₂N₈A₂N₈A₂ (A/A/A). Fine mapping of the ERB-2 site indicated that this A/A/A and the immediate franking sequences contained motifs for the estrogen response element. This region had a higher affinity for the nuclear scaffold and was included in the core region of the nucleosome structure. However, binding of the nuclear factor(s) to the motifs and disruption of nucleosome structure occurred without ATP. These results suggest that a class of periodic bent DNA could act as a site of multiple interactions among the nuclear scaffold, core histones and nuclear factors. ( J Nippon Med Sch 1998; 65 : 459-470)