Demonstration of an ecdysteroid receptor in a cultured cell line of Drosophila melanogaster.

Abstract

Incubation of the high-speed supernatant from the Kc cell line of D. melanogaster with [3H]ponasterone A results in significant binding of the ligand as determined by gel filtration and dextran-coated charcoal binding assays. In vivo exposure of the Kc line to [3H]ponasterone A for 30 min results in a marked binding of the ligand by a KCl-soluble nuclear extract. With both the cytosol and nuclear preparations, the binding has specificity and a low dissociation constant (3 .times. 10-9 M). The labeling of the nuclear preparation exhibits a saturation at approximately 7 .times. 10-10 M, which probably reflects the molar concentration of cytoplasmic receptors.