Two signalling pathways specify localised expression of the Broad-Complex in Drosophila eggshell patterning and morphogenesis

• Published in: Development (Cambridge) Vol. 124; no. 22; pp. 4639 - 4647
• Main Authors: Deng, W M, Bownes, M
• Format: Journal Article
• Language: English
• Published: England The Company of Biologists Limited 01.11.1997
• Subjects: Animals; DNA-Binding Proteins; Drosophila melanogaster - genetics; Drosophila melanogaster - growth & development; Drosophila melanogaster - metabolism; Drosophila Proteins; Female; Gene Expression Regulation, Developmental; Genes, Insect; In Situ Hybridization; Insect Proteins - genetics; Male; Nerve Tissue Proteins; Oocytes - growth & development; Oocytes - metabolism; Proto-Oncogene Proteins - genetics; Signal Transduction; Transcription Factors - genetics; Transforming Growth Factor alpha; Transforming Growth Factors - genetics; Zinc Fingers - genetics
• ISSN: 0950-1991; 1477-9129
• DOI: 10.1242/dev.124.22.4639

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.