title: Two signalling pathways specify localised expression of the Broad-Complex in Drosophila eggshell patterning and morphogenesis.
abstract: The Drosophila eggshell, which has a pair of chorionic appendages (dorsal appendages) located asymmetrically along both the anterior/posterior and dorsal/ventral axes, provides a good model to study signal instructed morphogenesis. We show that the Broad-Complex, a gene encoding zinc-finger transcription factors, is essential for the morphogenesis of dorsal appendages and is expressed in a bilaterally symmetrical pattern in the lateral-dorsal-anterior follicle cells during late oogenesis. This is induced and specified along the dorsoventral axis by an epidermal growth factor receptor signalling pathway, which includes a localised transforming growth factor-alpha like molecule, Gurken, in the oocyte and the Drosophila EGF receptor homologue, Torpedo, in the surrounding somatic follicle cells. Furthermore, the precisely localised expression of BR-C along the AP axis requires a separate signalling pathway, initiated by a transforming growth factor-beta homologue, Decapentaplegic, in nearby follicle cells. These two signalling pathways, one from the oocyte and the other from the follicle cells, co-ordinately specify patches of follicle cells to express the Broad-Complex in a unique position in respect to both major axes, which in turn directs the differentiation of the dorsal appendages in the correct position on the eggshell.
authors.affiliation: Institute of Cell and Molecular Biology, University of Edinburgh, UK.
authors.forename: W M
authors.initials: WM
authors.lastname: Deng
authors.forename: M
authors.initials: M
authors.lastname: Bownes
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D017403:In Situ Hybridization; D019476:Insect Proteins / Q000235:genetics; D008297:Male; D009419:Nerve Tissue Proteins; D009865:Oocytes / Q000254:growth & development / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics*; D016211:Transforming Growth Factor alpha; D015291:Transforming Growth Factors / Q000235:genetics; D016335:Zinc Fingers / Q000235:genetics
chemical_list: C102117:Br protein, Drosophila; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D009419:Nerve Tissue Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D016211:Transforming Growth Factor alpha; C064196:dpp protein, Drosophila; C083730:grk protein, Drosophila; C083884:pnt protein, Drosophila; D015291:Transforming Growth Factors