To date, six human α3-fucosyltransferases (α1,3-FUTs) have been cloned. α3- fucosyltransferase-IX (Fuc-TIX, FUT9) is the newest member of the six human α3- FUTs, and has been cloned by an expression cloning method from a mouse brain cDNA library (Kudo et al. 1998). All the α1,3-FUT members, including those of Helicobacter pylori (Ge et al. 1997), possess the conserved amino acid stretch FxL/VxFENS/TxxxxYxTEK as a motif of α1,3-FUT. The phylogenetic tree of α1,3- FUTs indicates that the α1,3-FUT genes evolved by independent gene duplication between vertebrates and Caenorhabditis elegans. There are four clusters in the vertebrate α1,3-FUT gene family, corresponding to the FUT3-FUT5-FUT6 gene cluster, FUT4, FUT7, and FUT9 gene subfamilies. The FUT9 gene family seems to be the first to diverge from the ancestral gene (Kaneko et al. 1999a). The FUT9 gene does not cross-hybridize with the other five α1,3-FUT genes. The FUT9 amino acid sequence is quite different from those of the other five α1,3-FUTs which share highly homologous sequences. More interestingly, the amino acid sequence of FUT9 (Fut9) is very highly conserved between mouse and human. The degree of conservation is almost equivalent to that of the α-actin gene. This indicates that FUT9 is under a strong selective pressure for preservation during evolution. Mouse has only three functional α1,3- Fut genes, Fut4, Fut7, and Fut9, corresponding to human FUT4, FUT7, and FUT9 genes. FUT9 (Fut9) transfers Fuc from GDP-Fuc to the GlcNAc residue of type-2 chain with an α1,3-linkage, resulting in the synthesis of Lewis X (Lex) epitope, Galβ1-4(Fucα1- 3)GlcNAc-R. The FUT9 gene is localized at 6q16 in human (Kaneko et al. 1999b), and the mouse Fut9 gene was mapped at chromosome 4 (unpublished data, 1998).
KeywordsFUT9 Gene Acceptor Substrate GlcNAc Residue Mature Granulocyte Namalwa Cell
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- Allendoerfer KL, Magnani JL, Patterson PH (1995) FORSE-1, an antibody that labels regionally restricted subpopulations of progenitor cells in the embryonic central nervous system, recognizes the Lex carbohydrate on a proteoglycan and two glycolipid antigens. Mol Cell Neurosci 6:381–395PubMedCrossRefGoogle Scholar
- Kaneko M, Kudo T, Iwasaki H, Ikehara Y, Nishihara S, Nakagawa S, Sasaki K, Shiina T, Inoko H, Saitou N, Narimatsu H (1999a) α1,3-fucosyltransferase IX (Fuc-TIX) is very highly conserved between human and mouse: molecular cloning, characterization and tissue distribution of human Fuc-TIX. FEBS Lett 452:237–242PubMedCrossRefGoogle Scholar
- Nakayama F, Nishihara S, Iwasaki H, Okubo R, Kaneko M, Kudo T, Nakamura M, Karube M, Narimatsu H (2001) CD15 expression in mature granulocytes is determined by α1,3-fucosyltransferase IX (FUT9), but in promyelocytes and monocytes by α1,3-fucosyltransferase IV (FUT4). J Biol Chem 276:16100–16106PubMedCrossRefGoogle Scholar
- Nishihara S, Iwasaki H, Kaneko M, Tawada A, Ito M, Narimatsu H (1999) α1,3-fucosyltransferase 9 (FUT9; Fuc-TIX) preferentially fucosylates the distal GlcNAc residue of polylactosamine chain while the other four α1,3FUT members preferentially fucosylate the inner GlcNAc residue. FEBS Lett 462:289–294PubMedCrossRefGoogle Scholar
- Warren HS, Altin JG, Waldron JC, Kinnear BF, Parish CR (1996) A carbohydrate structure associated with CD15 (Lewis X) on myeloid cells is a novel ligand for human CD2. J Immunol 156:2899–2873Google Scholar