Dr. Guild is studying a program of gene expression which is important to the development of the fruit fly Drosophila melanogaster. Sequential expression of the genes in this program is the larval salivary gland is regulated by the steroid hormone ecdysone and proceeds through a cascade of transcriptional regulation. The Broad-Complex (BR-C) locus encodes multiple products and acts early in this cascade to regulate the expression of downstream (late) genes. Dr. Guild will characterize BR-C products in order to learn how these early genes communicate with late genes. By taking a genetic approach he should be able to identify which RNA products serve in this capacity. He will test the idea that different BR-C products play roles in different but parallel tissue specific gene expression programs by developing product specific probes for different BR-C RNAs and proteins. In addition, he will determine whether BR-C products interact in a direct way with any other loci in the salivary gland cascade by surveying this polytene genome for bound BR-C products. %%% This proposal is concerned with the hormone regulated expression of a complicated genetic locus involved in metamorphosis in Drosophila, a model organism for the study of developmental genetics.
