Broad-Complex-mediated transcriptional regulation in Drosophila salivary glands

Pamela S Guay, University of Pennsylvania


The steroid hormone 20-OH ecdysone triggers a classic and well-defined program of chromosome puffing that is assumed to reflect changes in transcriptional activity in Drosophila salivary glands. Mutations in each of four Broad-Complex locus (BRC) complementation groups were analyzed for their effects on the expression of other genes that reside in several major salivary gland puffs. RNA blot analysis showed that the rbp function of the BRC was required for the transcription of six genes in the 71E late puff and was the first demonstration that an ecdysone-induced early gene controls the transcription of late genes within the puffing cascade. In addition, the rbp function was required for the transcription of four intermolt genes (Sgs-3, Sgs-4, Sgs-5, and 71E Gene VII). Mutations in the broad, l(1)Bc and l(1)2Bd functions of the BRC had no effect on the expression of the genes examined. RNA blot analysis also showed that not all possible BRC transcripts were expressed in third instar salivary glands. No differences in BRC expression patterns were seen in wild-type versus rbp-mutant salivary glands. Also, when the coding regions of each of the possible BRC transcripts were examined using single strand conformation polymorphism analysis, no evidence for point mutations which would lead to the rbp mutational phenotypes was found. These data suggest that the BRC is a multifunctional regulator of gene expression. It is likely to control transcription of genes in many tissues at the onset of metamorphosis.

Subject Area

Molecular biology

Recommended Citation

Guay, Pamela S, "Broad-Complex-mediated transcriptional regulation in Drosophila salivary glands" (1992). Dissertations available from ProQuest. AAI9308585.