Steroid hormones act in conjunction with receptor proteins to regulate the expression of target genes, ensuring that these genes are activated in the right tissues and at the right times. Although we have some understanding of how steroid hormones and their receptors control gene transcription in cultured mammalian cells, we understand little about how these effects on gene expression result in the dramatic developmental changes associated with steroid hormone function. This central question is difficult to address using vertebrate animals, because it is difficult to perform whole animal and genetic studies with vertebrates. The fruit fly, Drosophila melanogaster, in contrast, provides an ideal model system for unraveling the molecular mechanisms of steroid hormone action in the context of an intact animal. Drosophila undergoes a dramatic transition from larva to adult fly that is called metamorphosis.
Metamorphosis is directed by a single steroid hormone called ecdysone.
We are currently carrying out genetic, phenotypic, and molecular characterizations of mutations in a gene that appears to play a key role in directing transcriptional and developmental responses to ecdysone. By examining the mechanisms whereby ecdysone regulates metamorphosis in the fly, we hope to gain a better understanding of how steroid hormones control developmental processes in general. A Molecular Mechanism for the Stage-Specificity of the Drosophila Prepupal Genetic Response to Ecdysone. Olfactory Physiology in the Drosophila Maxillary Palps Requires the Visual System Gene rdgB . Temporal Differences in Ecdysone-Regulated Gene Expression at the Onset of Drosophila Metamorphosis.