Characterization of a specific ecdysteroid receptor-DNA complex reveals common properties for invertebrate and vertebrate hormone-receptor/DNA interactions

A gel-filtration assay has been developed with which the specific interaction between Drosophila melanogaster ecdysteroid receptor and the 20-hydroxy-ecdysone responsive element of the hsp27 gene promoter region was characterized in terms of complex formation, saturation of DNA binding and the apparent molecular mass of the complex. The hsp27 DNA-binding sequence for ecdysteroid receptor in vitro was delimited by footprinting and mutational analysis. The combined results show that ecdysteroid receptor binds as a dimer to an imperfect palindromic sequence (GGTTCAATGCACT) closely resembling the structures of the different vertebrate steroid-hormone-responsive elements reported so far