Influence of Lewis α1-3/4-L-Fucosyltransferase (FUT3) Gene Mutations on Enzyme Activity, Erythrocyte Phenotyping, and Circulating Tumor Marker Sialyl-Lewis a Levels

Abstract

Fucosylated glycoproteins carrying ␣1-4 fucose residues are of importance for cell adhesion and as tumor markers. The Lewis gene, FUT3, encodes the only known ␣1-4-fucosyltransferase (FucT), and individuals who are deficient in this enzyme type as Lewis-negative on erythrocytes. We examined the mutational spectrum of the Lewis gene in Denmark and found 6 different mutations. Five, T59G, T202C, C314T, G508A, and T1067A, were frequent, and one, C445A, was only detected in one out of 40 individuals. Allele-specific polymerase chain reaction as well as cloning of FUT3 alleles showed that the 202 and 314 mutations were co-located on the same allele. COS7 cells transfected with an allele having the 202/314 mutations lacked enzyme activity. Polymerase chain reaction-cleavage assays were established for the genotyping of healthy individuals as well as 20 genuine Lewis-negative cancer patients and 10 non-genuine. The latter have Lewis-negative erythrocytes but saliva ␣1-4FucT activity. The genuine Lewis-negative individuals had mutations on both FUT3 alleles. In 66 healthy individuals, a gene dosage effect was detected as FUT3 heterozygous individuals had a lower ␣1-4FucT activity in saliva than did homozygous wild-type individuals. The lower enzyme level in heterozygous individuals resulted in a significantly (p < 0.04) lower level of circulating sialyl-Lewis a structure in serum. This has the clinical impact that cut-off levels in tumor marker assays should be defined on the basis of genotyping. In the group of non-genuine Lewis-negative cancer patients, whose erythrocytes convert from Lewis-positive to Lewis-negative during the disease, FUT3 heterozygosity was significantly (p < 0.05) more common.

Lewis enzyme (α1–3/4 fucosyltransferase) polymorphisms do not explain the Lewis phenotype in the gastric mucosa of a Portuguese population

“…All the polymorphisms we have identified were previously reported in other populations (Elmgren et al 1993(Elmgren et al , 1996Koda et al 1993;Nishihara et al 1994;Ørntoft et al 1996;Pang et al 1996). The frequency of Lewis negative blood group phenotype we have observed (10.2%) is very similar to the frequency (10%) reported by Watkins (1980) in Caucasians.…”

“…The three polymorphisms are described in all the populations previously studied (Elmgren et al 1993(Elmgren et al , 1996Koda et al 1993;Liu et al 1999;Mollicone et al 1994;Nishihara et al 1994;Ørntoft et al 1996) and their frequency, whenever it was evaluated, was similar to the one we observed in the present study: 59T>G was observed with an allele frequency of 0.43 in 15 cases; 314C>T was observed with an allele frequency of 0.57 in 15 cases of individuals from Denmark (Elmgren et al 1996). Polymorphism 202T>C has a higher allele frequency in Denmark (0.60) (Elmgren et al 1996).…”

“…The 59T>G polymorphism is localised in the transmembrane domain and does not affect the enzyme activity, though it can switch the FucT III cell localisation from the Golgi apparatus to the cytoplasm (Koda et al 1993;Mollicone et al 1994;Narimatsu et al 1996). All the other polymorphisms described until now are located in the catalytic domain: 202T>C, 314C>T, 445C>A, 508G>A, 1067T>A (Elmgren et al 1996;Liu et al 1999;Narimatsu et al 1996;Nishihara et al 1999;Ørntoft et al 1996), 304C>A, 370T>G, 848G>A, 667G>A and 808G>A (Pang et al 1996(Pang et al , 1998. These Lewis gene variants codify enzymes with a lower activity (314C>T, 304C>A and 370T>G) or an inactive FucT III (202T>C, 508GaA, 1067T>A, 667G>A and 808G>A).…”

Significance of Individual Point Mutations, T202C and C314T, in the Human Lewis (FUT3) Gene for Expression of Lewis Antigens by the Human α(1,3/1,4)-Fucosyltransferase, Fuc-TIII

“…This has also recently been observed in studies on French individuals from the Reunion island. 2 The significance of this allele was recently confirmed in expression and enzymatic studies on transfected COS-7 cells (38), where some of our own unpublished FUT3-primers were used for PCR amplifications. It was hypothesized in this latter study that the C314T mutation of the le 202-314 allele might be the more important of the two mutations for introducing the Lewis negative phenotype on erythrocytes.…”

Article Molecular analysis of three FUT3 gene single nucleotide polymorphisms and their relationship with the lewis erythrocytary phenotype in a human population of japanese-ancestry living in Tomé Açu, a town in the Brazilian Amazon

“…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(Elmgren et al, , 1996Mollicone 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).…”