The FUT3 gene (originally named the Le gene) expresses galactoside 3(4)-L-fucosyltransferase present on the Golgi membrane. FUT3 catalyses the α1,4 and α1,3 addition of fucose to Type 1 and Type 2 oligosaccharide chains respectively, thereby playing a role in Lewis blood group determination (Kukowska-Latallo et al. 1990). Here, the addition of fucose to the subterminal N-acetylglucosaminyl (GlcNAc) residue of Type 1 chains in an α1,4 linkage forms the Lewis A antigen (LeA). In Lewis negative (Le(a- b-)) individuals, FUT3 is inactivated by either of two mutations resulting in a single amino acid substitution in the catalytic region (Nishihara et al. 1993). LeA is found on red blood cells (~20%) and in saliva and other secretions (>90%) of Europeans. LeA is a water-soluble antigen and red blood cells acquire Lewis specificity by adsorbing it onto their surfaces from blood plasma.
Nishihara, S, Yazawa, S, Iwasaki, H, Nakazato, M, Kudo, T, Ando, T, Narimatsu, H
Kukowska-Latallo, JF, Larsen, RD, Nair, RP, Lowe, JB
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