Glycosaminoglycan and glycoprotein synthesis by cranial neural crest cells in vitro

In the developing chick embryo, cranial neural crest cells, that will subsequently give rise to facial mesenchyme tissues, migrate beneath the surface ectoderm in a cell-free and hyaluronate-rich matrix. To determine how the crest cells could contribute to this matrix, we cultured crest cells from stage 9 embryos for 2 days and then labeled them for 18--20 h with various precursors of glycosaminoglycans (GAG) and glycoproteins. [3H]fucose and [3H]glucosamine were incorporated into Pronase-sensitive macromolecules associated with the cell layer, but little labeled glycoprotein was released into the medium. Hyaluronate was the major GAG synthesized and was distributed between the cells and medium. Less chondroitin-sulfate was synthesized. In comparison, older cultures as well as fibroblasts produced different proportions of GAG. Our results confirm the autoradiographic findings of Pratt et al. (1975) and suggest that crest cells may contribute GAG to the matrix during migration.