Carbohydrate-binding component of amphibian embryo cell surfaces: Restriction to surface regions capable of cell adhesion

Abstract

Superficial cells from early amphibian embryos display regional specializations of their celF surfaces. That portion of the plasma membrane facing the perivitelline space (apical surface) is nonadhesive, whereas, in the same cell, the lateral and basal portions of the plasma membrane will adhere to other cells. These adhesive differences are maintained on single cells that have been dissociated from the intact embryo. Few formalinized sheep erythrocytes bound to the apical (nonadhesive) portion of the cell surface, whereas the lateral and basal (adhesive) portions bound large numbers of erythrocytes. Thus both the cell surface oligomannosyl-specific carbohydrate-binding component (detected by erythrocyte resetting) and cell surface mannose residues [detected by Con A binding (5, 11)] colocalize to those portions of the cell that are adhesive and are excluded from those portions that are nonadhesive. The correspondence of the distribution of the amphibian cell surface carbohydrate-binding component and the Con A receptors suggests that the Con A receptors could function as the endogenous receptors for the endogenous cell-surface lectin that has oligomannosyl specificity. The apparent restriction of the amphibian embryo lectin to only the adhesive surfaces of the superficial cell suggests that it could play a role in the adhesive interactions of these cells. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact. MATERIALS AND METHODS

The masking effect of sialic acid on Con A, PNA and SBA ectoderm binding sites during neurulation in the bantam chick embryo

“…It has also been suggested that Con A-binding sites on cell surfaces are involved in establishing the adhesiveness in neurulation of chicks (Lee et al 1976) and in nasal fold fusion of mice (Burk et al 1979). Mannose has previously been thought to play a role in cell adhesion in teratocarcinoma stem cells (Grabel et al 1979), in early amphibian embryonic cells (Roberson and Armstrong 1980) and in migrating neural crest cells (Milos and Wilson 1986b). In our experiments the number of these sites was not so significant.…”

On the possible role of endogenous lectins in early animal development

“…The first report on endogenous lectins of amphibian embryos was that of Roberson and Armstrong (1980), who reported the presence of oligomannosyl-specific lectin activity in extracts of early embryos of Rana pipiens. By determining the mannose-inhibitable binding of mammalian erythrocytes to different areas of the cell surface, these investigators suggested that the lectin was associated with the areas of the cell surface that were involved in cell-adhesion, while it was absent in the apical non-adhesive surfaces of the blastula.…”

Correlation of glycosylation forms with position in amino acid sequence

“…High-mannose structures have been demonstrated as significant if not major components of N-linked oligosaccharides exposed on the surfaces of many cell types (Ceccarini and P. H. Atkinson, unpublished observations) as have complex structures (reviewed in 1). How the various forms of these types of oligosaccharides appear on the cell surface is not directly known, but they are involved in recognition functions in specific adhesion of cells (57,128,130) and in development (152). Aside from their involvement in cell surface recognition, high-mannose oligosaccharides are involved in directing lysosomal enzymes to their correct subcellular compartment (for review, see reference i 14).…”