Estrogen receptors alpha and beta exhibit different estradiol and estrogenresponse element binding in the presence of nonspecific DNA

Estrogen receptors (ER) alpha and beta bind estradiol (E-2) and estrogen re sponse element (ERE) DNA sequences with high affinities. The different migr ation of ER-ERE complexes in the presence or absence of nonspecific DNA sug gests that DNA may affect ER conformation and function. We measured the rat e of E-2-ER association and specific ER-ERE binding capacity (ERE-SBC) in t he presence or absence of nonspecific DNA, Whereas DNA did not alter the ra te of E-2-ER alpha association, both ERE-containing and plasmid DNA decreas ed the rate of E, association with ERP, Poly(dI-dC) decreased ERE-SBC of ER alpha, but did not affect the ERE-SBC of ER beta salmon sperm genomic DNA decreased the ERE-SBC of ER alpha, but increased the ERE-SBC of ERP, We spe culate that interaction of ER with genomic DNA may contribute to ER activat ion and play a role in the observed differences in transcriptional activity of ER alpha and ER beta. (C) 2001 Academic Press.