FUT3 transfers Fuc to Type 1 chains to form LeA

The <i>FUT3</i> gene (originally named the <i>Le</i> 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.

FUT3基因（最初命名为Le基因）表达位于高尔基膜上的半乳糖苷3(4)-L-岩藻糖基转移酶。FUT3催化α1,4和α1,3岩藻糖分别添加到I型和II型寡糖链，从而在利氏血型决定中发挥重要作用（Kukowska-Latallo等，1990年）。在此，岩藻糖以α1,4键合方式添加到I型链的亚末端N-乙酰氨基葡萄糖（GlcNAc）残基上，形成利氏A抗原（LeA）。在利氏阴性（Le(a- b-)）个体中，FUT3通过催化区域（Nishihara等，1993年）的两个突变之一失活，导致单个氨基酸替换。LeA存在于欧洲人的红细胞（约20%）以及唾液和其他分泌物（超过90%）中。LeA是一种水溶性抗原，红细胞通过从血浆中吸附其表面来获得利氏特异性。