EPIDERMAL FUCOSYLATION OF CELL SURFACE GLYCOPROTEIN

When Ulex europeus agglutinin I (UEA) conjugated with fluorescein isothio-cyanate is applied to tissue sections from the cutaneous epidermis of the new-born rat, the lectin binds to the surfaces of cells in the layer immediately above the basal layer but not to the cells in the basal layer itself. The latter cells bind the isolectin I-B4, from Griffonia simplicifolia (GS I-B.4). The addition of a fucosyl residue to the oligosaccharide of the glycoproteln found on the surface of the basal cell can account for the change in lectin-binding specificity which occurs as the basal cell moves toward the cutaneous surface and becomes a spinous cell. The epidermis of the newborn rat has the necessary transferase to convert a glycoprotein with binding-specificity for GS I-B4 to binding specificity for UEA by adding a fucosyl residue from GDP:L-fucose. Cell-surface glycoconjugates are altered during differentiation in the mammalian cutaneous epidermis (l-6) as in other differentiating and developing systems (7-18). These changes may have physiological significance since glyco