DEVELOPMENTAL AND BIOCHEMICAL-STUDIES OF ADHESIVE SPECIFICITY AMONG EMBRYONIC RETINAL CELLS

A pattern of cell-cell adhesion within the chick embryo neural retina follows a dorsoventral gradient in which cells at either end show maximal affinity for each other. Developmental and biochemical approaches were applied to analyze the basis of this adhesive pattern. When retinal cells were prepared from eyes that were inverted 180.degree. in situ prior to retinal differentiation, an inverted pattern of adhesive preference resulted. Adhesive preference apparently is determined early in embryogenesis. Trypsinization of either dorsal or ventral retinal cells destroyed their adhesive preference. Treatment with neuraminidase resulted in a differential loss of adhesive preference by dorsal retinal cells. This effect could be mimicked by mild oxidation with NaIO4. Since periodate inactivation of adhesive preference could be reversed by subsequent borohydride treatment, borotritiate was used to label those cell surface molecules crucial to the reactivation of adhesive preference. Fluorographs prepared after polyacrylamide gel electrophoresis revealed that periodate stimulated the appearance of a small number of radioactively labeled bands. Adhesive preference apparently is mediated by glycoconjugates, possibly sialoglycoproteins, on the dorsal cell surface.