Matrix Glycoproteins in Early Mouse Development and in Differentiation of Teratocarcinoma Cells

Abstract

This chapter discusses the matrix glycoproteins and their localization in the early mouse embryo. Of the matrix components studied, laminin is the first to be detected by immunofluorescence in the early embryo. Analogous to the appearance of laminin in compaction is its appearance in the aggregating cells of the mouse metanephrogenic mesenchyme during differentiation of kidney tubules. After formation of kidney tubules, laminin is restricted to basement membranes, as is the case in adult tissues. The appearance of fibronectin in the inner cell mass of the blastocyst coincides with the formation of the first embryonic basement membrane. Localization of fibronectin to basement membranes and loose connective tissue is also characteristic for this protein later in development. Of the collagenous matrix components, basement membrane collagen type IV is similarly located in the preimplantation embryo and in the embryoid bodies as fibronectin. The basement membrane collagens probably form a group of several related proteins and it is possible that they may have individual developmental characteristics.