20-P026 Phenotypic consequences of pacman exoribonuclease misexpression in Drosophila development

Cell migration has been studied extensively in vitro, however, fewer studies address this subject in vivo. Our aim is to determine in vivo, the role of the actin regulatory protein, Ena. To enable this we are studying Drosophila hemocytes in the developing embryo. Hemocytes are the primary immune cells of Drosophila and during development they follow stereotyped pathways to distribute throughout the embryo. Using the Gal4UAS system to express GFP specifically in hemocytes allows us to visualize the migrating hemocytes using the confocal microscope. This system is also used to overexpress Ena or interfere with its function. Here we show that Ena localizes to the leading edge of the lamellipodia and tips of filopodia. Furthermore, Ena positively regulates filopodial and lamellipodial protrusions, as previously illustrated in fibroblasts in vitro. However, whereas Ena negatively regulates velocity of fibroblasts in vitro it actually increases the velocity of hemocytes in vivo. This key difference highlights the importance of studying gene function in vivo.