title: Regulation of broad by the Notch pathway affects timing of follicle cell development.
abstract: During Drosophila oogenesis, activation of Notch signaling in the follicular epithelium (FE) around stage 6 of oogenesis is essential for entry into the endocycle and a series of other changes such as cell differentiation and migration of subsets of the follicle cells. Notch induces the expression of zinc finger protein Hindsight and suppresses homeodomain protein Cut to regulate the mitotic/endocycle (ME) switch. Here we report that broad (br), encoding a small group of zinc-finger transcription factors resulting from alternative splicing, is a transcriptional target of Notch nuclear effector Suppressor of Hairless (Su(H)). The early pattern of Br in the FE, uniformly expressed except in the polar cells, is established by Notch signaling around stage 6, through the binding of Su(H) to the br early enhancer (brE) region. Mutation of the Su(H) binding site leads to a significant reduction of brE reporter expression in follicle cells undergoing the endocycle. Chromatin immunoprecipitation results further confirm Su(H) binding to the br early enhancer. Consistent with its expression in follicle cells during midoogenesis, loss of br function results in a delayed entry into the endocycle. Our findings suggest an important role of br in the timing of follicle cell development, and its transcriptional regulation by the Notch pathway.
authors.affiliation: Department of Biological Science, Florida State University, Tallahassee, FL 32306-4370, USA.
authors.forename: Dongyu
authors.initials: D
authors.lastname: Jia
authors.affiliation: Department of Biological Science, Florida State University, Tallahassee, FL 32306-4370, USA.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Tamori
authors.affiliation: BIOSS Centre for Biological Signalling Studies & Institute for Biology I, University of Freiburg, Schänzlestr. 18, 79104 Freiburg, Germany.
authors.forename: George
authors.initials: G
authors.lastname: Pyrowolakis
authors.affiliation: Department of Biological Science, Florida State University, Tallahassee, FL 32306-4370, USA. Electronic address: wumin@bio.fsu.edu.
authors.forename: Wu-Min
authors.initials: WM
authors.lastname: Deng
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D029721:Drosophila Proteins / Q000096:biosynthesis / Q000235:genetics*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics; D004848:Epithelium / Q000196:embryology / Q000378:metabolism; D005260:Female; D018398:Homeodomain Proteins / Q000096:biosynthesis; D009687:Nuclear Proteins / Q000096:biosynthesis; D009866:Oogenesis / Q000235:genetics / Q000502:physiology; D006080:Ovarian Follicle / Q000166:cytology / Q000196:embryology* / Q000502:physiology; D034622:RNA Interference; D034741:RNA, Small Interfering; D051880:Receptors, Notch / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: C102117:Br protein, Drosophila; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; C497759:N protein, Drosophila; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D051880:Receptors, Notch; D012097:Repressor Proteins; C088731:Su(H) protein, Drosophila; D014157:Transcription Factors; C066381:ct protein, Drosophila; C106513:peb protein, Drosophila
keywords: Endocycle; Mitotic cycle; Notch; broad