Investigating the role of Pico in axis formation in Drosophila melanogaster

Abstract

In all organisms, axis formation is the essential first step towards the development of a basic body plan. This aspect of pattern formation requires extensive signaling between different cells. Drosophila oogenesis is a model system for studying axis formation. During oogenesis, signaling between the oocyte and the surrounding somatic follicle cells is required to establish the anterior-posterior axis. First, the oocyte signals to specify certain somatic cells as posterior follicle cells (PFCs). Then, the PFCs signal back to the oocyte, causing the repolarization of the oocyte microtubule network. The identity and mechanism of this second signal are unknown. In this thesis, we present Pico, as a novel regulator of posterior signaling. In Pico knockdown egg chambers, we show that oocyte polarity and posterior signaling are disrupted. Moreover, we report that Pico is expressed in the PFCs and may regulate the developmentally-crucial EGFR signaling pathway. We conducted preliminary experiments to test Pico’s interactions with different proteins and attempted to generate a Pico mutant for use in future experiments. Further work is necessary to characterize Pico’s role in posterior signaling and research in this area will help reveal the identity and mechanism of posterior signaling. An increased understanding of posterior signaling will help to elucidate the process of axis formation and provide insight into the fundamental research question asking how a single egg can develop into a highly complex organism. Additionally, increased knowledge about Pico and its interactors may provide insight into actin-related disease processes in mammals.