Extracellular Matrix Functions in Amphibian Gastrulation

The coordinated cell and tissue behaviors that give rise to the movements of gastrulation are influenced by extracellular matrix (ECM). In amphibian embryos fibronectin (FN) is first assembled into fibrils in a spatially and temporally regulated manner at the onset of gastrulation. Studies of the role of FN in amphibian gastrulation have revealed that in addition to providing a substratum for cell adhesion and migration, ECM regulates many other aspects of cell behavior. Cell–ECM interaction modulates cell–cell adhesion. FN contributes to the polarized cell protrusive activities that generate a variety of cell movements. ECM can serve as a repository for growth factors, contributing to the spatial and temporal regulation of growth factor signals. The physical properties of ECM also contribute to morphogenetic behaviors through mechanical signaling and influencing tissue force generation. ECM itself is very dynamic. It is stretched, moved, and remodeled by the cells and tissues whose behaviors it influences.