Intercellular Coordination and Robustness

We explore the mechanical nature of Ventral Furrow Formation (VFF) in Drosophila melanogaster using two complementary models that represent cells as mechanically excitable objects that interact through pairwise potentials. The first model focuses on the apical (outer) surface of the embryo. We represent the apical surfaces of cells as mechanically active discs and examine the initiating phase of VFF in which up to 40% of cells experience correlated stochastic constrictions, forming cellular constriction chains (CCCs). We define quantities that can be used to determine mechanical feedback mechanisms that would give rise to the observed CCC morphology, and our findings indicate that cellular sensitivity to tensile mechanical feedback is a factor in the formation of CCCs. The second model considers cells to be fully three dimensional, soft, non-spherical objects and focuses on the cross-section of the embryo. Driven by continued apical constrictions, VFF culminates in the internalization of a region of cells on the underside of the embryo. Our models show how multiple mechanisms work in concert to ensure completion of the invagination process, and we have found that mechanical feedback can allow for successful furrow closure in systems with perturbed or weakened constrictions.