Bab2 Functions as an Ecdysone-Responsive Transcriptional Repressor during Drosophila Development

• Published in: Cell reports (Cambridge) 2020-07, Vol.32 (4), p.107972-107972, Article 107972
• Main Authors: Duan, Jianli, Zhao, Yunpo, Li, Haichao, Habernig, Lukas, Gordon, Michael D., Miao, Xuexia, Engström, Ylva, Büttner, Sabrina
• Format: Article
• Language: English
• Subjects: Animals; Bab2; Broad; DNA-Binding Proteins - metabolism; Drosophila; Drosophila melanogaster - embryology; Drosophila melanogaster - genetics; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; ecdysone; Ecdysone - physiology; EcR/USP; Gene Expression Regulation, Developmental - genetics; glue genes; Larva - metabolism; Metamorphosis, Biological - genetics; salivary gland; Sgs genes; steroid hormone; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription, Genetic - genetics; transcriptional regulation
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2020.107972

Drosophila development is governed by distinct ecdysone steroid pulses that initiate spatially and temporally defined gene expression programs. The translation of these signals into tissue-specific responses is crucial for metamorphosis, but the mechanisms that confer specificity to systemic ecdysone pulses are far from understood. Here, we identify Bric-à-brac 2 (Bab2) as an ecdysone-responsive transcriptional repressor that controls temporal gene expression during larval to pupal transition. Bab2 is necessary to terminate Salivary gland secretion (Sgs) gene expression, while premature Bab2 expression blocks Sgs genes and causes precocious salivary gland histolysis. The timely expression of bab2 is controlled by the ecdysone-responsive transcription factor Broad, and manipulation of EcR/USP/Broad signaling induces inappropriate Bab2 expression and termination of Sgs gene expression. Bab2 directly binds to Sgs loci in vitro and represses all Sgs genes in vivo. Our work characterizes Bab2 as a temporal regulator of somatic gene expression in response to systemic ecdysone signaling. [Display omitted] •Bab2 controls developmental stage-specific gene expression programs•Bab2 terminates gene expression downstream of EcR/USP and Broad in salivary glands•Bab2 directly binds to glue gene promoter sequences•High levels of Bab2 drive premature salivary gland degeneration The steroid hormone ecdysone governs Drosophila development via initiation of spatially and temporally defined gene expression programs. Duan et al. establish Bab2 as an ecdysone-responsive suppressor of gene expression in Drosophila salivary glands, downstream of the early transcription factor Broad, following the larval-prepupal ecdysone pulse.