The Broad‐Complex directly controls a tissue‐specific response to the steroid hormone ecdysone at the onset of Drosophila metamorphosis

• Published in: The EMBO journal Vol. 13; no. 15; pp. 3505 - 3516
• Main Authors: Kalm, L., Crossgrove, K., Von Seggern, D., Guild, G.M., Beckendorf, S.K.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 01.08.1994
• Subjects: Animals; Base Sequence; Binding Sites; Biochemistry. Physiology. Immunology; Biological and medical sciences; Consensus Sequence; DNA - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Drosophila; Drosophila - genetics; Drosophila - growth & development; Ecdysone - physiology; Female; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation - genetics; Genes, Insect - genetics; Glue Proteins, Drosophila - genetics; Insecta; Invertebrates; Male; Metamorphosis, Biological - genetics; Models, Genetic; Molecular Sequence Data; Physiology. Development; Regulatory Sequences, Nucleic Acid - genetics; Transcription, Genetic - genetics; Zinc Fingers - genetics; Transcription; Zinc finger structure; Insecta; Drosophila; Tissue specificity; Salivary gland; Gene expression; Structure function relationship; Drosophilidae; Signal transduction; Ecdysteroide; Arthropoda; Development; Trans acting regulatory factor; Ecdysone; Invertebrata; Metamorphosis; Diptera
• ISSN: 0261-4189; 1460-2075
• DOI: 10.1002/j.1460-2075.1994.tb06657.x

In Drosophila, all of the major metamorphic transitions are regulated by changes in the titer of the steroid hormone ecdysone. Here we examine how a key regulator of metamorphosis and primary ecdysone response gene, the Broad‐Complex, transmits the hormonal signal to one of its targets, the Sgs‐4 glue gene. We show that Broad‐Complex RNAs accumulate in mid third instar larval salivary glands prior to Sgs‐4 induction, as expected for the products of a gene that regulates the timing of Sgs‐4 activation. The Broad‐Complex codes for a family of zinc finger transcriptional regulators. We have identified a number of binding sites for these proteins in sequences known to regulate the timing of Sgs‐4 induction, and have used these sites to derive a binding consensus for each protein. Some of these binding sites are required in vivo for Sgs‐4 activity. In addition, rbp+, a genetically defined Broad‐Complex function that is required for Sgs‐4 induction, acts through these Broad‐Complex binding sites. Thus, the Broad‐Complex directly mediates a temporal and tissue‐specific response to ecdysone as larvae become committed to metamorphosis.