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.

The Ecdysone and Notch Pathways Synergistically Regulate Cut at the Dorsal–Ventral Boundary in Drosophila Wing Discs

“…Previously, we applied a mouse monoclonal anti-Br-core antibody 25E9 (Emery et al, 1994), and confirmed the ubiquitous expression of Br in Drosophila wing discs during the late third instar larval stage (Jia et al, 2014). To study the loss-of-function of Br in wing discs, we generated br-RNAi knockdown cells in the posterior compartment of wing discs by the tissue-specific driver en-gal4 .…”

“…1B). The homozygous clones of a br amorphic allele, br npr-3 (Jia et al, 2014) recapitulated the phenotype of Cut absence (Fig. 1C), indicating Br is essential for proper Cut expression.…”

“…Br is an early response gene of the steroid hormone ecdysone, which is essential for the initiation of metamorphosis (Karim et al, 1993; Fletcher and Thummel, 1995), and was recently found as a direct downstream target of Notch signaling during Drosophila oogenesis (Jia et al, 2014). Here, we report that through gain- and loss-of-function studies, Br is involved in regulating Cut expression in the DV boundary region.…”

E(y)1/TAF9 mediates the transcriptional output of Notch signaling in Drosophila

“…1C,D). In addition, the expression of another follicle-cell-specific Notch reporter broad-earlyenhancer-lacZ (brE-lacZ), recently identified by our laboratory (Jia et al, 2014), was also decreased in e(y)1-depleted follicle cells (supplementary material Fig. S1B).…”

<b>Isolamento e caracterização de células indiferenciadas de ovos embrionados de <i>Aedes aegypti</i> (Linnaeus 1762)</b>

“…Estudos realizados recentemente com células-tronco de insetos foram descritas em vários tecidos, porém os tipos celulares mais estudados são células-tronco de intestino médio (LOEB et al, 1996;LOEB et al, 1999;LOEB et al, 2003;MICCHELLI;PERRIMON, 2006;OHLSTEIN;SPRADLING, 2006;BATON;RANFORD-CARTWRIGHT, 2007;HAKIM et al, 2009;NARDI et al, 2010;NAVASCUÉS et al, 2012), e do folículo ovariano (PETERSON et al;SWEVERS;IATROU, 2003;SWEVERS et al, 2005;BELLES;PIULACHS, 2014;JIA et al, 2014 ) tanto em células embrionárias como também em adultas a partir de uma vasta diversidade de insetos.…”