Article

Molecular basis for plasma α(1,3)-fucosyltransferase gene deficiency (FUT6)

INSERM U.178, Villejuif, France.
Journal of Biological Chemistry (Impact Factor: 4.57). 05/1994; 269(17):12662-71.
Source: PubMed

ABSTRACT

While most humans express an alpha(1,3)-fucosyltransferase in plasma, 9% of individuals on the isle of Java (Indonesia) do not express this enzyme. Ninety-five percent of these plasma alpha(1,3)-fucosyltransferase-deficient individuals have Lewis negative phenotype on red cells, suggesting strong linkage disequilibrium between these two traits. To define the molecular basis for this plasma deficiency and to determine which of two candidate human alpha(1,3)-fucosyltransferase genes encode this enzyme (FUT5 and FUT6), we cloned and analyzed alleles at these two loci from an Indonesian individual deficient in plasma alpha(1,3)-fucosyltransferase activity. Single base pair changes were identified in the coding region of each gene, relative to previously published wild type alleles. These changes in turn yield three codon changes in FUT5 and three in FUT6. The codon changes in the FUT5 gene do not yield detectable diminutions in alpha(1,3)-fucosyltransferase activity when tested by expression in transfected COS-1 cells, and none of the FUT5 alleles co-segregate with plasma alpha(1,3)-fucosyltransferase deficiency in Indonesian pedigrees. By contrast, two of the codon changes in the FUT6 alleles inactivate this gene when tested by expression in transfected COS-1 cells. One of these inactivating changes is a missense mutation (Glu-247-->Lys) within the enzyme's catalytic domain. The other inactivating mutation represents a nonsense mutation (Tyr-315-->stop) that truncates the COOH terminus of the enzyme by 45 amino acids. The Glu-247-->Lys missense mutation is present in double dose in the nine plasma alpha(1,3)-fucosyltransferase-deficient individuals tested, whereas the nonsense mutation at tyrosine 315 is present in double dose in just one of these persons. These results demonstrate that the alpha(1,3)-fucosyltransferase activity in human plasma is encoded by the FUT6 gene and that the missense mutation within codon 247 of this gene is responsible for deficiency of this activity in these Indonesian families.

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    • "The most frequent FUT3 SNPs are the 202T > C, 314C > T, 508G > A and 1067T > A polymorphisms (le genes) which affect and inactivate the catalytic domain of FucT III enzyme (Nishihara et al., 1993, 1994; Kudo et al., 1996), while a further SNP, 59T > G, is known to cause the substitution of an amino acid in the transmembrane region but its effect on enzymatic activity has not yet been defined (Elmgren et al., 1996). The FUT3 202T > C; 314C > T and 59T > G polymorphisms have been reported in all populations in which this gene has been studied (Elmgren et al., 1993, 1996; Mollicone et al., 1994; Nishihara et al., 1994; Kudo et al., 1996; Ørntoft et al., 1996; Liu et al., 1999; Cakir et al., 2002), while the 508G > A and 1067T > A polymorphisms have been identified at a high frequency in Japanese populations (Koda et al., 1993; Nishihara et al., 1994). "
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    ABSTRACT: The Lewis blood group system involves two major antigens, Leª and Leb. Their antigenic determinants are not primary gene products but are synthesized by the transfer of sugar subunits to a precursory chain by a specific enzyme which is the product of the FUT3 gene (Lewis gene). The presence of three FUT3 gene single nucleotide polymorphisms (SNPs) (59T > G; 508G > A and 1067T > A) was related to the Lewis phenotype of erythrocytes from 185 individuals of Japanese ancestry living in the town of Tomé-Açu in the Brazilian Amazon region. This relationship was detected using a serological hemagglutination test and the Dot-ELISA assay along with the molecular technique PCR-RFLP. We found that the three SNPs investigated in this study only accounted for a proportion of the Lewis-negative phenotype of the erythrocytes.
    Full-text · Article · Mar 2007 · Genetics and Molecular Biology
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    • "The FUT3 and FUT5 enzymes can use both type 1 and type 2 precursors as substrates, FUT3 having a marked preference for type 1 and FUT5 for type 2. The FUT4, FUT6, FUT7 and FUT9 enzymes catalyze addition of a fucose exclusively onto the type 2 precursor [5]. Like the FUT1 and FUT2 genes, polymorphisms have been described for FUT3, FUT5, FUT6 and more recently for FUT7 [6] [7] [8]. Individuals lacking a functional FUT3 allele are called 'Lewis negative' and are characterized by the red cell phenotype Le(a-b-). "
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    ABSTRACT: Antigens of the ABH and Lewis histo-blood group family have been known for a long time. Yet their biological meaning is still largely obscure. Based on the available knowledge about the genes involved in their biosynthesis and about their tissue distribution in humans and other mammals, we discuss here the selective forces that may maintain or propagate these oligosaccharide antigens. The ABO, alpha 1,2fucosyltransferase and alpha 1,3fucosyltransferase enzyme families have been generated by gene duplications. Members of these families contribute to biosynthesis of the antigens through epistatic interactions. We suggest that the highly polymorphic genes of each family provide intraspecies diversity that allows coping with diverse and rapidly evolving pathogens. In contrast, the genes of low frequency polymorphism are expected to play roles at the cellular level, although they may be dispensable at the individual level. In addition, some members of these three gene families are expected to be functionally redundant and may either provide a reservoir for additional diversity in the future or become inactivated. We also discuss the role of the ABH and Lewis histo-blood group antigens in pathologies such as cancer and cardiovascular diseases, but argue that it is merely incidental and devoid of evolutionary impact.
    Full-text · Article · Aug 2001 · Biochimie
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    • "In several Java families the plasma α1,3fucosyltransferase activity has been found to be deficient. This deficiency was a result of a mutation in the FUT6 gene (Mollicone et al., 1994). The linkage relationship between a α3-FucT VI mutation and deficiency of plasma fucosyltransferase activity was further confirmed by work of van Dijk and associates (Brinkman-Van der Linden et al., 1996): The missense mutation in the α3-FucT VI gene led to a complete absence of α3-fucosylation of serum glycoproteins. "
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    ABSTRACT: The major alpha1,3fucosyltransferase activity in plasma, liver, and kidney is related to fucosyltransferase VI which is encoded by the FUT6 gene. Here we demonstrate the presence of alpha1, 3fucosyltransferase VI (alpha3-FucT VI) in the human HepG2 hepatoma cell line by specific activity assays, detection of transcripts, and the use of specific antibodies. First, FucT activity in HepG2 cell lysates was shown to prefer sialyl-N-acetyllactosamine as acceptor substrate indicating expression of alpha3-FucT VI. RT-PCR analysis further confirmed the exclusive presence of the alpha3-FucT VI transcripts among the five human alpha3-FucTs cloned to date. alpha3-FucT VI was colocalized with beta1,4galactosyltransferase I (beta4-GalT I) to the Golgi apparatus by dual confocal immunostaining. Pulse/chase analysis of metabolically labeled alpha3-FucT VI showed maturation of alpha3-FucT VI from the early 43 kDa form to the mature, endoglycosidase H-resistant form of 47 kDa which was detected after 2 h of chase. alpha3-FucT VI was released to the medium and accounted for 50% of overall cell-associated and released enzyme activity. Release occurred by proteolytical cleavage which produced a soluble form of 43 kDa. Monensin treatment segregated alpha3-FucT VI from the Golgi apparatus to swollen peripheral vesicles where it was colocalized with beta4-GalT I while alpha2,6(N)sialyltransferase remained associated with the Golgi apparatus. Both constitutive secretion of alpha3-FucT VI and its monensin-induced relocation to vesicles analogous to beta4-GalT I suggest a similar post-Golgi pathway of both alpha3-FucT VI and beta4-GalT I.
    Preview · Article · Dec 1999 · Glycobiology
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