Drosophila tissues with different metamorphic responses to ecdysone express different ecdysone receptor isoforms

Responses to Ecdysone Express D ifferent Ecdysone Receptor lsoforms

In D. melanogaster a pulse of the steroid hormone ecdysone triggers the larval-to-adult metamorphosis, a complex process in which this hormone induces imaginal t issues to generate adult structures and larval tissues to degenerate. We show that the EcR gene encodes three ecdysone receptor isoforms (EcR-A, EcR-81 , and EcR-B2) that have common DNAand hormone-binding domains but different N-termi...

Drosophila Ecdysone Receptor Mutations Reveal Functional Differences among Receptor Isoforms

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 embr...

Ecdysone Differentially Regulates Metamorphic Timing Relative To

Specific transcriptional responses to juvenile hormone and ecdysone in Drosophila.

Previous studies have shown that ecdysone (E), and its immediate downstream product 20-hydroxyecdysone (20E), can have different biological functions in insects, suggesting that E acts as a distinct hormone. Here, we use Drosophila larval organ culture in combination with microarray technology to identify genes that are transcriptionally regulated by E, but which show little or no response to 2...

The Ecdysone Receptor Puzzle

The present article reviews some recent findings on the functional ecdysone † receptor which is a heterodimer of two proteins: ecdysone receptor (EcR) and Ultraspiracle (USP). Emphasis is given to some unique aspects of this receptor, in particular to its dimerization, binding to DNA, and transactivation capabilities. The effects of ligands (ecdysone, juvenile hormone) on these functions are di...