Ultraspiracle et le récepteur de l'ecdysone ou les relations dans la famille des récepteurs hormonaux nucléaires de la drosophile aux mammifères

Abstract

A member of the nuclear receptor superfamily has been identified as corresponding to the ultraspiracle gene of Drosophila. Mutants of this gene show various defects throughout the life cycle of the animal, from the egg-shell formation to the adult eye one, while overexpression does not affect its development. The Ultraspirade protein presents similarities with the mammalian RXR receptors, and forms heterodimers with RXR mammalian partners. In Drosophila it forms heterodimers with the protein identified as the receptor for the steroid hormone of insects, ecdysone. Heterodimer formation is necessary for both binding to a bona fide Ecdysone response element and hormone binding. Implications of these findings for the understanding of the interactions within the nuclear receptor superfamily are discussed.