Functional Analysis of Ecdysteroid Receptor from Drosophila melanogaster “In Vitro”

Abstract

Ecdysone receptor (EcR) was expressed in vertebrate cells to study its functional properties in the absence of the heterodimerization partner Ultraspiracle (Usp) and to avoid interference with endogenous receptor isoforms. Comparison of different isoforms affords determination of receptor concentration, which was achieved either by determination of ligand binding sites by Scatchard analysis or by quantitative evaluation of specific Western blot signals, but not by normalization on transfection efficiency as determined by cotransfection with a constitutive reporter plasmid. Ligand-and DNA-binding, and transcriptional activity of EcR isoforms and the influence of Ultraspiracle (Usp) were described.