My laboratory has established the border cells in the Drosophila ovary as a model system for a systematic, forward genetic approach to study invasive cell behavior and epithelial to mesenchymal transitions. Epithelial cells are tightly connected to each other through a variety of cell-cell junctions and they are polarized, with distinct apical and basolateral sides. During embryonic development epithelial cells sometimes dissolve their junctions with their neighbors and become mesenchymal.
Mesenchymal cells have a less rigid shape and are more likely to be motile.
Epithelial to mesenchymal transitions, as well as the reverse process, are extremely important for normal development. In addition, these transitions are important in wound healing, and tumor cells that develop from epithelial cells must transform into motile cells in order to metastasize. Our goal is to identify the changes in gene expression, cell adhesion and cytoskeletal organization that are required for the epithelial to mesenchymal transition in order to understand this process at a biochemical level. The border cells develop initially as part of the epithelium of 1100 follicle cells, which surround the cluster of 15 nurse cells and one oocyte in a structure known as an egg chamber. Eventually the nurse cells will contribute all of the cytoplasm to the oocyte which will mature into an egg.