title: Drosophila ecdysone receptor mutations reveal functional differences among receptor isoforms.
abstract: The steroid hormone ecdysone directs Drosophila metamorphosis via three heterodimeric receptors that differ according to which of three ecdysone receptor isoforms encoded by the EcR gene (EcR-A, EcR-B1, or EcR-B2) is activated by the orphan nuclear receptor USP. We have identified and molecularly mapped two classes of EcR mutations: those specific to EcR-B1 that uncouple metamorphosis, and embryonic-lethal mutations that map to common sequences encoding the DNA- and ligand-binding domains. In the larval salivary gland, loss of EcR-B1 results in loss of activation of ecdysone-induced genes. Comparable transgenic expression of EcR-B1, EcR-B2, and EcR-A in these mutant glands results, respectively, in full, partial, and no repair of that loss.
authors.affiliation: Department of Developmental Biology, Stanford University Medical Center, California 94305, USA.
authors.forename: M
authors.initials: M
authors.lastname: Bender
authors.forename: F B
authors.initials: FB
authors.lastname: Imam
authors.forename: W S
authors.initials: WS
authors.lastname: Talbot
authors.forename: B
authors.initials: B
authors.lastname: Ganetzky
authors.forename: D S
authors.initials: DS
authors.lastname: Hogness
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D004440:Ecdysone / Q000502:physiology; D005091:Exons; D005260:Female; D017344:Genes, Insect; D005804:Genes, Lethal; D005816:Genetic Complementation Test; D008297:Male; D008675:Metamorphosis, Biological; D016296:Mutagenesis; D011987:Receptors, Steroid / Q000235:genetics* / Q000502:physiology
chemical_list: D011987:Receptors, Steroid; C055469:ecdysone receptor; D004440:Ecdysone