Functional ecdysone receptor is the product of EcR and Ultraspiracle genes

Tso Pang Yao, Barry Marc Forman, Zeyu Jiang, Lucy Cherbas, J. Don Chen, Michael McKeown, Peter Cherbas, Ronald M. Evans

Research output: Contribution to journalArticlepeer-review

772 Scopus citations


ALTHOUGH the biological activity of the insect moulting hormone ecdysone, is manifested through a hormonally regulated transcriptional cascade associated with chromosomal puffing1-3, a direct association of the receptor with the puff has yet to be established. The cloned ecdysone receptor 4 (EcR) is by itself incapable of high-affinity DNA binding or transcriptional activation. Rather, these activities are dependent on heterodimer formation with Ultraspiracle5 (USP) the insect homologue of vertebrate retinoid X receptor6. Here we report that native EcR and USP are co-localized on ecdysone-responsive loci of polytene chromosomes. Moreover, we show that natural ecdysones selectively promote physical association between EcR and USP, and conversely, that high-affinity hormone binding requires both EcR and USP. Replacement of USP with retinoid X receptor produces heterodimers with distinct pharmacological and functional properties. These results redefine the ecdysone receptor as a dynamic complex whose activity may be altered by combinatorial interactions among subunits and ligand.

Original languageEnglish (US)
Pages (from-to)476-479
Number of pages4
Issue number6454
StatePublished - 1993
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General


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