Presence of fibronectin during early embryogenesis in amphibian Pleurodeles waltlii.

The presence of fibronectin (FN) has been investigated during the early development of Pleurodeles waltlii by using indirect immunofluorescence and gel electrophoresis methods. Between the early blastula and late gastrula stages, fluorescent staining was detected on cell surface, especially in cells from the blastocoele roof and the marginal zone. Through gastrulation, extracellular material which was accumulated in the area of the blastopore occurred heavily stained for FN. Sodium metaperiodate-sodium boro[3H]hydride has been used to label the surface carbohydrate residues. Labelled glycoproteins were characterized by sodium dodecyl sulphate and two-dimensional polyacrylamide gel electrophoresis coupled with fluorography. Autoradiograms revealed a 220K cell surface glycoprotein which was co-migrating with monomers of FN. The results suggested that FN may be involved in the early morphogenesis of the amphibian embryo.