|M.Sc Student||Shlyakhover Evgeny|
|Subject||Regulation of SIMU Expression in Drosophila Embryonic|
|Department||Department of Medicine||Supervisor||Dr. Estee Kurant|
|Full Thesis text|
Apoptosis of excessive cells and consequent removal of their corpses via phagocytosis is crucial for proper morphogenesis of organs and tissues during embryonic development. Recognition of apoptotic bodies is performed via interaction between “eat-me” signals on the dying cell membrane and engulfment receptors situated on the phagocytic cell surface. Six Microns Under (SIMU) is a non-signaling phosphatidylserine engulfment receptor, which is highly expressed during Drosophila development in “professional” and “non-professional” phagocytes i.e. macrophages, glia and ectoderm. Previous work in our lab has shown that SIMU is required for recognition and engulfment of apoptotic particles during embryogenesis but lack or extent of apoptosis do not influence SIMU expression, suggesting that SIMU expression is part of a developmental program controlling phagocytic function of glia and macrophages. Moreover, it was shown that glial cells missing (gcm), a master regulator of glial cell fate determination, which is also expressed in macrophages, was responsible for SIMU expression in glia, but not in macrophages. In this work, we demonstrate that serpent, a homolog of vertebrate GATA factors and a key regulator in macrophage differentiation pathway is both necessary and sufficient for SIMU expression. In addition, we reveal that Serpent likely regulates SIMU expression through its multiple binding sites in the simu promoter. Finally, we show that in embryonic macrophages serpent is required for expression of two other phagocytic receptors - Draper and Croquermort.