My laboratory studies the mechanisms of animal morphogenesis with a focus on epithelial cells. Epithelial cells have a highly polarized structure compared to non-epithelial (mesenchymal) cells and they are organized in two-dimensional sheets. How the polarized structure of epithelial cells develops and is maintained and how morphogenetic movements of epithelial sheets are controlled are fundamental questions of animal development that are currently only poorly understood. We use the fruit fly Drosophila as a genetic model system and a variety of technical approaches that range from histology and immunohistochemistry to genetics and molecular biology to identify and characterize genes that control cell structure and cell movement during development. Our current work focuses on the characterization of a number of cadherins, a group of adhesion molecules that are important morphogenetic regulators and include DE-cadherin, the human homolog of which is a tumor suppressor gene. A second project analyzes the function of the Crumbs protein that controls epithelial cell structure. Mutations in the human homolog of this gene cause a degeneration of the retina that leads to blindness.