Extracellular Matrix in the Blastocoel of Newt Gastrula: its Effects on Dissociated Embryonic Cells and some Aspects of its Biochemical Nature

Abstract

The extracellular matrix (ECM) was removed manually from the blastocoel of freeze-dried embryos of the newt, Cynops pyrrhogaster. In vitro examination demonstrated that the substratum of the blastocoelic ECM (B-ECM) promoted adhesion and spreading of dissociated gastrula cells, while little effect was shown on dissociated blastula cells under the same conditions. Furthermore, the B-ECM promoted locomotion of the spreading gastrula cells. SDS-polyacrylamide gel electrophoretic analysis revealed that the B-ECM contained three major proteins (108, 97 and 30 kilodaltons), which co-migrate with yolk proteins, and a 190-kilodalton protein. The yolk proteins extracted from yolk platelets were found also to act effectively as an strong adhesive substratum for dissociated gastrula cells, however they did not promote cell locomotion. These results suggested that the yolk proteins in the B-ECM may act as an effective adhesion substance for dissociated gastrula cells.