EXPRESSION OF DISTINCT FUCOSYLATED OLIGOSACCHARIDES AND CARBOHYDRATE-MEDIATED ADHESION EFFICIENCY DIRECTED BY 2 DIFFERENT ALPHA-1,3-FUCOSYL-TRANSFERASES - COMPARISON OF E-SELECTIN-MEDIATED AND L-SELECTIN-MEDIATED ADHESION

Among five different human alpha 1-->3 fucosyltransferases cloned, fuc osyltransferases III (Fuc-TIII) and IV (Fuc-TIV) differ significantly from each other. Fuc-TIII transfers a fucose to both sialylated and no nsialylated N-acetyllactosamine, but Fuc-TIV apparently transfers a fu cose only to neutral N-acetyllactosamine, In this study, Chinese hamst er ovary (CHO) cells were stably transfected with Fuc-TIII or Fuc-TIV, and the resultant cell lines, CHO-FTIII and CHO-FTIV, were compared f or the carbohydrate structures and for their binding to E-selectin or L-selectin. CHO-FTIII and CHO-FTIV cells were labeled metabolically wi th [H-3]galactose, and glycopeptides obtained from these cells were fr actionated by serial lectin affinity chromatography. The fractionated glycopeptides were then subjected to various combinations of exoglycos idase treatment or endo-beta-galactosidase digestion. The results obta ined can be summarized as follows. CHO-FTIII cells express sialyl Lewi s(x), Lewis(x), and VIM-2 structures, whereas CHO-FTIV cells express o nly an Le(x) structure with a small amount of VIM-2 structure. When CH O-FTIII and CHO-FTIV cells were tested for adhesion to E-selectin expr essed by tumor necrosis factor-activated endothelial cells and to an E -selectin chimeric protein, only CHO-FTIII cells were found to adhere well to E-selectin. Moreover, both CHO-FTIII and CHO-FTIV cells failed to adhere to an L-selectin chimeric protein. T hese results clearly i ndicate that FT-III and FT-IV direct distinctly different fucosylated oligosaccharides. This difference in oligosaccharide structures result s in an entirely different efficiency in adhesion to E-selectin. The r esults also demonstrate that expression of sialyl Le(x) itself is not sufficient for L-selectin binding.