Going in Circles gets you Somewhere – Mechanisms Controlling Egg Chamber Elongation in Drosophila

During development, discrete organs and entire body plans emerge from the coordinate actions of individual cells. These complex morphogenetic events require dynamic regulation of cell shape, polarity, and adhesion across cell populations, as well as reciprocal interactions between cells and their extracellular matrix (ECMs). My lab seeks to understand how these diverse cellular behaviors are orchestrated to produce an organ’s shape. To this end, we are using genetic and cell biological approaches in Drosophila to investigate how a simple organ-like structure called an egg chamber is transformed from a spherical to an ellipsoidal shape. Egg chamber elongation depends on a dramatic collective cell migration event, in which the egg chamber’s outer epithelial cells crawl along their adjacent basement membrane ECM. This process causes the entire egg chamber to rotate within the matrix. This seminar will discuss two key aspects of this motility. First, I will show how tissue movement synergizes with new protein secretion to construct a polarized network of fibrils within the basement membrane that are required for elongation morphogenesis. Second, I will introduce a new planar signaling system that controls the collective migration itself.