Studying Nonproliferative Roles for Egfr Signaling in Tissue Morphogenesis Using Dorsal Closure of the Drosophila Embryo.

For several decades, genetic analysis in Drosophila has made important contributions to the understanding of signaling by Egfr. Egfr has been well characterized with regard to its oncogenic potential but is also being studied for its roles in organismal development. We have recently developed dorsal closure of the Drosophila embryo as a system for characterizing Egfr regulation of events that do not involve proliferation, as no cell divisions occur during this process. Dorsal closure is essentially a developmental wound healing event with parallels to vertebrate developmental epithelial fusions such as neural tube closure and palate fusion. We describe here a set of materials and protocols for studying Egfr signaling during dorsal closure, including assessing effects of altering Egfr signaling on other pathways, gene expression and, using live imaging, morphogenesis and programmed cell death. Although this "tool kit" is designed for looking at Egfr, it can be readily adapted to look at the participation of any signaling molecule in dorsal closure.