title: Analysis of transcriptional activity mediated by Drosophila melanogaster ecdysone receptor isoforms in a heterologous cell culture system.
abstract: Ecdysteroid regulation of gene transcription in Drosophila melanogaster and other insects is mediated by a heterodimer comprised of Ultraspiracle (USP) and one of three ecdysone receptor (EcR) isoforms (A, B1 and B2). This study revealed that the EcR/USP heterodimer displays isoform-specific capabilities. EcRB1 is normally induced with a form of USP that is missing its DNA-binding domain (DBD), although potentiation by juvenile hormone (JH) III is reduced. The EcRA and B2 isoforms, however, display almost no response to ecdysteroids with the DBD(-) USP. A mutation, K497E, in the shared ligand-binding domain of the EcR isoforms caused elevated EcRB2-specific affinity for a canonical ecdysone response element. The effects of directed modification and mutagenesis offer a strategy for developing hypotheses and considerations for studying in vivo function.
authors.affiliation: Center for Biotechnology, Genomics and Health Research, University of North Carolina-Greensboro, Greensboro, NC 27402-6170, USA.
authors.forename: J
authors.initials: J
authors.lastname: Beatty
authors.forename: T
authors.initials: T
authors.lastname: Fauth
authors.forename: J L
authors.initials: JL
authors.lastname: Callender
authors.forename: M
authors.initials: M
authors.lastname: Spindler-Barth
authors.forename: V C
authors.initials: VC
authors.lastname: Henrich
mesh_terms: D000818:Animals; D016466:CHO Cells; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004268:DNA-Binding Proteins / Q000378:metabolism; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000378:metabolism*; D004441:Ecdysterone / Q000031:analogs & derivatives / Q000494:pharmacology; D024202:Electrophoretic Mobility Shift Assay; D015151:Immunoblotting; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements / Q000187:drug effects; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D020033:Protein Isoforms; D011987:Receptors, Steroid; D014157:Transcription Factors; C066030:USP protein, Drosophila; C055469:ecdysone receptor; C467903:ecdysone receptor A, insect; C055348:muristerone A; D004441:Ecdysterone