Widespread Gene Conversion of Alpha-2-Fucosyltransferase Genes in Mammals
Widespread Gene Conversion of Alpha-2-Fucosyltransferase Genes in Mammals
复制标题
DOI：
10.1007/s00239-009-9239-0
复制
发表时间：
2009-07-01
影响因子：
3.9
通讯作者：
Le Pendu, Jacques
中科院分区：
文献类型：
--
作者：
Abrantes, Joana;Posada, David;Le Pendu, Jacques
α-2-岩藻糖基转移酶 (α 2FT) 是参与 α 2 岩藻糖基化聚糖结构生物合成的酶。在哺乳动物基因组中，存在三个串联的 alpha 2FT 基因：FUT1、FUT2 和 Sec1，每个基因都包含在一个 sin-le 外显子内。有人认为这些基因起源于两次连续的复制，首先生成 FUT1，然后生成 FUT2 和 Sec1。尽管基因转换被认为是基因家族协同进化的主要机制，但之前对灵长类 a2FT 的研究未能检测到它，尽管最近在人类等位基因中报道了 FUT2 和 Sec1 之间基因转换的发生。我们工作的主要目的是对哺乳动物 α 2FT 的分子进化开展更广泛的研究。序列比较使我们确认这三个基因是通过两轮复制出现的。此外，我们能够在灵长类动物的基部和几个非灵长类物种中检测到涉及 FUT2 和 Sec I 的多个基因转换事件。在兔子中也检测到涉及 FUT1 和 FUT2 或 Sec1 的基因转换。 α2FTs 基因之间的基因转换程度似乎具有物种特异性，可能与这些基因的功能分化有关。除兔子外，在编码催化结构域C末端部分的区域中没有观察到基因转化。在该区域中，FUT1 和 FUT2 相同但 Sec1 不同的氨基酸数量高于蛋白质的其他部分。这一观察结果的生物学意义可能与功能限制有关。
The alpha-2-fucosyltransferases (alpha 2FTs) are enzymes involved in the biosynthesis of alpha 2fucosylated glycan structures. In mammalian genomes, there are three alpha 2FT genes located in tandem-FUT1, FUT2, and Sec1-each contained within a sin-le exon. It has been suggested that these genes originated from two Successive duplications, with FUT1 being generated first and FUT2 and Sec1 second. Despite gene conversion being considered the main mechanism of concerted evolution in gene families, previous studies of primates a2FTs failed to detect it, although the occurrence of gene conversion between FUT2 and Sec1 was recently reported in a human allele. The primary aim of our work was to initiate a broader study on the molecular evolution of mammalian alpha 2FTs. Sequence comparison leads us to confirm that the three genes appeared by two rounds of duplication. In addition, we were able to detect multiple gene-conversion events at the base of primates and within several nonprimate species involving FUT2 and Sec I. Gene conversion involving FUT1 and either FUT2 or Sec1 was also detected in rabbit. The extent of gene conversion between the alpha 2FTs genes appears to be species-specific, possibly related to functional differentiation of these genes. With the exception of rabbits, gene conversion was not observed in the region coding the C-terminal part of the catalytic domain. In this region, the number of amino acids that are identical between FUT1 and FUT2, but different in Sec1, is higher than in other parts of the protein. The biologic meaning of this observation may be related to functional constraints.