Extracellular matrix organized in embryonic cavities during induction of the embryonic axis in chick embryo.

Extracellular matrix (ECM) is detected as short, disorganized fibrils in the forming embryonic extracellular spaces shortly prior to the first morphogenetic cellular movements and interactions in the early chick embryo. As development progresses, the ECM is organized into an intricate network spanning the embryonic cavities. This dynamic entity undergoes relatively rapid changes in its organization pattern during the developmental period from morula to the induction of the neural plate. The ECM seems to preserve the exquisite architecture of the embryo and could guide migrating cells into defined pathways in the early embryo.