System-wide genomic and biochemical comparisons of sialic acid biology among primates and rodents -: Evidence for two modes of rapid evolution
System-wide genomic and biochemical comparisons of sialic acid biology among primates and rodents -: Evidence for two modes of rapid evolution
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DOI：
10.1074/jbc.m604221200
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发表时间：
2006-09-01
影响因子：
4.8
通讯作者：
Varki, Ajit
中科院分区：
文献类型：
--
作者：
Altheide, Tasha K.;Hayakawa, Toshiyuki;Varki, Ajit
许多脊椎动物基因参与了寡糖链与糖缀合物的生物学连接。这些基因在传统的基因本体分类中属于不同的组。然而，它们应该从功能和进化的角度在“生化系统”的方法，考虑每个单糖单位的生物合成，活化，运输，修饰，转移，回收，降解和识别一起进行评估。唾液酸（Sia）残基是位于脊椎动物细胞表面和分泌分子聚糖外端的单糖，介导内源性或外源性（病原体）受体的识别。多个基因组序列的可用性允许在灵长类动物和啮齿类动物之间对直接参与Sia生物学的所有基因进行系统范围的比较。采用这种方法，我们提出了进一步的证据，在CD 33相关的Sia识别Ig样凝集素的Sia结合结构域的加速进化。其他基因类别更为保守，包括编码将Sia残基连接至聚糖的唾液酸转移酶的那些。尽管这一保护，组织唾液酸化模式显示，这些物种之间的差异很大，大概是因为唾液酸转移酶的表达模式的快速演变。从这些和其他哺乳动物类群的红细胞和血浆糖肽的N-和O-聚糖的分析证实了这一现象。这些糖肽上的Sia修饰似乎也在经历快速进化。sialome的这种快速进化可能是由于生物体不断需要逃避使用Sia残基作为受体的微生物病原体。抑制性CD 33相关的Sia识别Ig样凝集素的Sia结合结构域的快速进化可能是次要的后果，因为这些抑制性受体大概需要跟上快速进化的“自我”-唾液酸体的识别。
Numerous vertebrate genes are involved in the biology of the oligosaccharide chains attached to glycoconjugates. These genes fall into diverse groups within the conventional Gene Ontology classification. However, they should be evaluated together from functional and evolutionary perspectives in a "biochemical systems" approach, considering each monosaccharide unit's biosynthesis, activation, transport, modification, transfer, recycling, degradation, and recognition. Sialic acid (Sia) residues are monosaccharides at the outer end of glycans on the cell-surface and secreted molecules of vertebrates, mediating recognition by intrinsic or extrinsic ( pathogen) receptors. The availability of multiple genome sequences allows a system-wide comparison among primates and rodents of all genes directly involved in Sia biology. Taking this approach, we present further evidence for accelerated evolution in Sia-binding domains of CD33-related Sia-recognizing Ig-like lectins. Other gene classes are more conserved, including those encoding the sialyltransferases that attach Sia residues to glycans. Despite this conservation, tissue sialylation patterns are shown to differ widely among these species, presumably because of rapid evolution of sialyltransferase expression patterns. Analyses of N- and O-glycans of erythrocyte and plasma glycopeptides from these and other mammalian taxa confirmed this phenomenon. Sia modifications on these glycopeptides also appear to be undergoing rapid evolution. This rapid evolution of the sialome presumably results from the ongoing need of organisms to evade microbial pathogens that use Sia residues as receptors. The rapid evolution of Sia-binding domains of the inhibitory CD33-related Sia-recognizing Ig-like lectins is likely to be a secondary consequence, as these inhibitory receptors presumably need to keep up with recognition of the rapidly evolving "self"-sialome.