Research Interests
My laboratory studies steroid hormone signaling during development in Drosophila. Our long-term goal is to understand the molecular and genetic mechanisms by which steroid hormones exert tissue-specific effects during development. In Drosophila, the steroid hormone ecdysone induces the larval-to-adult metamorphosis, a remarkable process in which many ecdysone target tissues undergo cell death while other target tissues differentiate to form adult structures. Ecdysone also controls important functions during embryogenesis and in reproduction. Our work focuses on the ecdysone receptor (EcR) gene that mediates ecdysone response in the fly. EcR encodes three nuclear receptors (EcR-A, EcR-B1, and EcR-B2) that are expressed with different tissue-specific and developmental profiles. Two types of EcR mutants have been isolated, those which inactivate all EcR isoforms and those which inactivate only the EcR-B1 isoform. The different phenotypes of these two classes of EcR mutants establish distinct temporal requirements for alternate EcR proteins and support a model in which different EcR proteins contribute to distinct tissue-specific responses to ecdysone. To test this model and to define the role that different ecdysone receptor isoforms play in mediating differential tissue-specific responses to ecdysone, we are screening for mutations that inactivate each of the EcR isoforms. In addition, we are testing the ability of the different EcR isoforms to functionally substitute for one another in vivo, using transgenic rescue experiments. Finally, we plan to identify novel ecdysone response genes by screening for genetic interactions with EcR mutants.