Expression cloning and characterization of a novel murine α1,3-fucosyltransferase, mFuc-TIX, that synthesizes the Lewis x (CD15) epitope in brain and kidney
Expression cloning and characterization of a novel murine α1,3-fucosyltransferase, mFuc-TIX, that synthesizes the Lewis x (CD15) epitope in brain and kidney
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DOI：
10.1074/jbc.273.41.26729
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发表时间：
1998-10-09
影响因子：
4.8
通讯作者：
Narimatsu, H
中科院分区：
文献类型：
--
作者：
Kudo, T;Ikehara, Y;Narimatsu, H
3-岩藻糖基-N-乙酰乳糖胺（刘易斯x，CD 15，SSEA-1）糖表位广泛分布于许多组织中，并在某些啮齿动物和人类组织（即脑和肺）以及小鼠早期胚胎中发育性表达。在这样的组织中，刘易斯x表位被认为参与细胞-细胞相互作用。我们利用表达克隆的方法从成年小鼠脑cDNA文库中克隆了一个新的小鼠α 1，3-岩藻糖基转移酶基因，命名为mFuc-TIX。在流式细胞术分析中，用mFuc-TIX基因稳定转染的Namalwa细胞显示刘易斯x表位显著增加，但唾液酸刘易斯x表位没有显著增加。如涉及寡糖作为受体底物的实验所见，mFuc-TIX将岩藻糖转移至乳糖-N-新四糖，但不转移至α 2，3-唾液酸乳糖-N-新四糖或乳糖-N-四糖。mFuc-TIX的底物特异性与小鼠骨髓型α 1，3-岩藻糖基转移酶（mFuc-TIV）的底物特异性相似。推导的mFuc-TIX的氨基酸序列由359个残基组成，表明是II型膜蛋白，并且在氨基酸序列水平上与先前克隆的α 1，3-岩藻糖基转移酶，即mFuc-TIV（48.4%）、小鼠Fuc-TVII（39.1%）和人Fuc-TIII（43.0%）显示出低程度的同源性。通过邻位连接法构建的α 1，3-岩藻糖基转移酶的系统发育树显示mFuc-TIX与其他α 1，3-岩藻糖基转移酶相当远。因此，mFuc-TIX不属于已知α 1，3Fuc-Ts的任何亚家族。北方印迹法和竞争性逆转录-聚合酶链反应法检测到mFuc-TIX主要在脑和肾中表达，而脑中未检测到mFuc-TIV。在原位杂交中，在神经元细胞中检测到mFuc-TIX转录本，但在包括星形胶质细胞的胶质细胞中未检测到。这些结果有力地表明，mFuc-TIX参与脑神经元中的刘易斯x合成，并且可能受到发育调节。
The 3-fucosyl-N-acetyllactosamine (Lewis x, CD15, SSEA-1) carbohydrate epitope is widely distributed in many tissues and is developmentally expressed in some rodent and human tissues, i.e. brain and lung, and mouse early embryo. In such tissues, the Lewis x epitope is considered to be involved in cell-cell interactions. We isolated a novel mouse alpha 1,3-fucosyltransferase gene, named mFuc-TIX, from an adult mouse brain cDNA library using the expression cloning method. On flow cytometric analysis, Namalwa cells transfected stably with the mFuc-TIX gene showed a marked increase in Lewis x epitopes but not sialyl Lewis x epitopes. As seen experiments involving oligosaccharides as acceptor substrates, mFuc-TIX transfers a fucose to lacto-N-neotetraose but not to either alpha 2,3-sialyl lacto-N-neotetraose or lacto-N-tetraose. The substrate specificity of mFuc-TIX was similar to that of mouse myeloid-type alpha 1,3-fucosyltransferase (mFuc-TIV). The deduced amino acid sequence of mFuc-TIX, consisting of 359 residues, indicated a type II membrane protein and shows low degrees of homology to the previously cloned alpha 1,3-fucosyltransferases, i.e. mFuc-TIV (48.4%), mouse Fuc-TVII (39.1%), and human Fuc-TIII (43.0%), at the amino acid sequence level. A phylogenetic tree of the alpha 1,3-fucosyltransferases constructed by the neighbor-joining method showed that mFuc-TIX is quite distant from the other alpha 1,3-fucosyltransferases. Thus, mFuc-TIX does not belong to any subfamilies of known alpha 1,3Fuc-Ts. The mFuc-TIX transcript was mainly detected in brain and kidney with the Northern blotting and competitive re verse transcription-polymerase chain reaction methods, whereas the mFuc-TIV transcript was not detected in brain with these methods. On in situ hybridization, the mFuc-TIX transcript was detected in neuronal cells but not in the glial cells including astrocytes. These results strongly indicated that mFuc-TIX participates in the Lewis x synthesis in neurons of the brain and may be developmentally regulated.