Cellular mechanisms of filopodia emission during the closing of the lens placode during embryogenesis

Abstract

The process of filopodia emission involves cytoskeleton rearrangement and it is well described in many cell types, in cell migration processes and in the embryonic epithelium movement. The decision between emission or not of filopodia is determined by various molecular pathways of actin polymerization. Among these, the CDC42-GTPase activity is an important factor on the formation of these cellular extensions. In lens morphogenesis studies during the chick embryo development, we observed in shooting the apical constriction of cells during placode invagination and the rearrangement of optic vesicle ectoderm cells. These observation led us to two innovative discoveries that involves sorting of three distinct populations of cells types in the pre-placoidal ectoderm and the filopodia emission by the most peripheral population. This work seeks to determine whether and how the filopodia emission is involved in the lens morphogenesis. To achieve this objective, we will quantificate filopodia and associate them with cell morphology and analyze the contribution of signaling pathway CDC42-GTPase in filopodia emission in this context.