Fucosyltransferase 7/FUT7: ProductsN-glycans, O-glycans and glycolipids are frequently fucosylated at terminal sites. Therefore, fucose is often part of a sugar epitope with important biological function. Well known fucose containing glycans include Lewis and ABO blood group antigens. Lewis epitopes are key elements involved in the leukocyte homing and extravasation process and thus are important for lymphocyte maturation and natural defense functions. Fucose-containing glycans also play critical roles in cell signaling and development. More than 10 fucosyltransferases have been cloned. FUT1 and FUT2 are alpha1-2 fucosyltransferases and are responsible for ABO blood-group antigen synthesis. FUT8 is an alpha1-6 fucosyltransferase that adds a fucose to the chitobiose core of N-glycans. FUT3, FUT4, FUT5, FUT6, FUT7 and FUT9 are alpha1-3 or alpha1-4 fucosyltransferases and are responsible for Lewis antigen generation. FUT7 plays an exclusive role for the biosynthesis of sialy Lewis X epitope (NeuAc alpha 2,3Gal beta 1,4[Fuc alpha 1,3]GlcNAc) that serves as a ligand in the E-selectin and P-selectin mediated adhesion of leukocytes to activated endothelium or platelets.