title: Fibronectin in early amphibian embryos. Migrating mesodermal cells contact fibronectin established prior to gastrulation.
abstract: The three-dimensional organisation of fibronectin (FN) in early amphibian embryos (Ambystoma mexicanum, Pleurodeles waltlii) was studied with the use of antibodies against amphibian-FN. Immunofluorescence labelling was performed on whole-mount specimens. It was shown that before gastrulation an extensive extracellular network consisting of anastomosed FN-fibrils underlies the roof of the blastocoel prior to the migration of mesodermal cells. Initially, FN-fibrils develop radially on the inner surface of ectodermal cells (early blastula stage) and become confluent there to elaborate a fibrillar network. During the late blastula stage the entire surface of the blastocoel roof (presumptive ectoderm and mesoderm) is covered by the FN-rich extracellular matrix. As gastrulation proceeds, the migrating mesodermal cells interact with the FN-fibrillar network. The results suggest that the FN-containing extracellular matrix plays an important role in mediating mesodermal cell-substratum contacts in gastrulating embryos. No FN-fibrils were found in other parts of the embryo.
mesh_terms: D000557:Ambystoma / Q000196:embryology*; D000558:Ambystoma mexicanum / Q000196:embryology*; D000818:Animals; D002465:Cell Movement; D005109:Extracellular Matrix / Q000032:analysis; D005353:Fibronectins / Q000032:analysis*; D005775:Gastrula / Q000166:cytology; D008648:Mesoderm / Q000166:cytology*; D009024:Morphogenesis; D010999:Pleurodeles / Q000196:embryology*; D012455:Salamandridae / Q000196:embryology*
chemical_list: D005353:Fibronectins