The Role of Bio-Mechanics in Somite Formation

Early vertebrate segmentation results from the creation of a series of metameric epithelial spheres called somites. While the timing of somite formation is believed to be regulated by a molecular level clock, the formation of somites is a self-organizing mechanical process that has received little attention so far. In this work, we build a 2D computer model of mesenchymal to epithelial transition process to explore the cellular mechanisms that promote somite organization. We focus on the first stage of somite formation, the establishment of the dorsal layer as an anterior propagating wave of cell maturation. First we explore and discuss the separate and combined contributions of cell polarization, adhesion and elongation to the formation of the dorsal layer. Finally, we explore the process of apical constriction and show how the forming layer is segmented into discrete units.