Molecular cloning and expression of a bovine alpha(1,3)-fucosyltransferase gene homologous to a putative ancestor gene of the human FUT3-FUT5-FUT6 cluster
Molecular cloning and expression of a bovine alpha(1,3)-fucosyltransferase gene homologous to a putative ancestor gene of the human FUT3-FUT5-FUT6 cluster
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DOI：
10.1074/jbc.272.13.8764
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发表时间：
1997-03-28
影响因子：
4.8
通讯作者：
Julien, R
中科院分区：
文献类型：
--
作者：
Oulmouden, A;Wierinckx, A;Julien, R
Southern印迹分析仅发现一个牛基因，对应于人类基因簇FUT 3-FUT 5-FUT 6。同源牛α（1，3）-岩藻糖基转移酶与人FUC-T3、FUC-T5和FUC-T6酶分别具有67.3%、69.0%和69.3%的氨基酸序列同一性。正如蛋白质序列比对、天冬酰胺连接糖基化的潜在位点和保守半胱氨酸所揭示的那样，牛酶是FUC-T3、FUC-T5和FUC-T6人类酶之间的中间体。转染COS-7细胞后，牛基因诱导了具有2型底物受体模式特异性的α（1，3）-岩藻糖基转移酶的合成，并诱导了岩藻糖基化2型表位（Le（x）和唾液酸-Le（x））的表达，但不诱导1型结构（Le（a）或唾液酸-Le（a））的表达，表明其具有与人血浆FUC-T6相似的受体特异性。然而，在牛血浆中未检测到酶活性。在牛肝、肾、肺和脑等组织中检测到基因转录物。在肾致密斑和胆管中发现2型唾液酸化Le（x）表位，在小肠和大肠上皮细胞刷状缘上检测到Le（x）和Le（y）表位，表明组织分布更接近人FUC-T3，但在任何牛组织中均未检测到岩藻糖基化1型结构（Le（a）、Le（B）或唾液酸化Le（a））。岩藻糖基转移酶基因的组合系统发育树上的遗传距离分析表明，牛基因是构成本FUT 3-FUT 5-FUTG簇的人类基因的祖先的直系同源物。
Only one bovine gene, corresponding to the human cluster of genes FUT3-FUT5-FUT6, was found by Southern blot analysis. The cognate bovine alpha(1,3)-fucosyltransferase shares 67.3, 69.0, and 69.3% amino acid sequence identities with human FUC-T3, FUC-T5, and FUC-T6 enzymes, respectively. As revealed by protein sequence alignment, potential sites for asparagine-linked glycosylation and conserved cysteines, the bovine enzyme is an intermediate between FUC-T3, FUC-T5, and FUC-T6 human enzymes. Transfected into COS-7 cells, the bovine gene induced the synthesis of an alpha(1,3)-fucosyltransferase enzyme with type 2 substrate acceptor pattern specificity and induced expression of fucosylated type 2 epitopes (Le(x) and sialyl-Le(x)), but not of type 1 structures (Le(a) or sialyl-Le(a)), suggesting that it has an acceptor specificity similar to the human plasma FUC-T6. However, no enzyme activity was detected in bovine plasma. Gene transcripts are detected on tissues such as bovine liver, kidney, lung, and brain. The type 2 sialyl-Le(x) epitope was found in renal macula densa and biliary ducts, and Le(x) and Le(y) epitopes were detected on the brush border of epithelial cells of small and large intestine, suggesting a tissue distribution closer to human FUC-T3, but fucosylated type 1 structures (Le(a), Le(b) or sialyl-Le(a)) were not detected at all in any bovine tissue. Analysis of genetic distances on a combined phylogenetic tree of fucosyltransferase genes suggests that the bovine gene is the orthologous homologue of the ancestor of human genes constituting the present FUT3-FUT5-FUTG cluster.