Ray Keller
Studies of the cellular and molecular basis of the convergence and extension movements of the body axis in early development of vertebrates, and similar movements in other systems, have received much attention recently with the finding that components of the planar cell polarity pathway of Drosophila appear to regulate the polarized cell behaviors underlying convergent extension. Based on studies of cell motility in explants and manipulations of the embryo and explants, we have proposed a cell traction-cell substrate model as a guide for analyzing the cell biology and biomechanics of how this polarized cell motility might produce the mediolateral intercalation of cells that occurs during convergent extension. It seems that nearly everyone thinks that this model has a stronger underpinning in experiment than we do, and therefore I will review of the evidence for it with a focus on what is not known about cell intercalation and what should be done. I will also present evidence that suggests that an epithelial mesenchymal transition generates forces in the urodele that are generated in Xenopus by mediolateral intercalation, and show that urodeles share a fundamental gastrulation mechanism with amniotes.
cytomechanical modules 2003 • back