Fibronectin synthesis during oogenesis and early development of the amphibian Pleurodeles waltlii.

Fibronectin (FN) synthesis during oogenesis and early embryogenesis of the amphibian Pleurodeles waltlii was investigated. The isotopically labelled amino acids [3H]leucine and [35S]methionine were incubated with oocytes or microinjected into embryos. Newly synthesized FN was analysed by polyacrylamide gel electrophoresis, using the high resolution two-dimensional gel system described by O'Farrell. With this method and fluorography we demonstrate that FN synthesis begins during oogenesis. De novo synthesized FN appears during cleavage and gastrulation. Using actinomycin D we show the presence of maternal messenger RNA coding for FN. It is translated during the cleavage and gastrulation stages.