Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan.
Immunogenetics. 2014 Mar;66(3):161-70. doi: 10.1007/s00251-014-0760-y. Epub 2014 Jan 28.
Non-human primates such as rhesus macaque and cynomolgus macaque are important animals for medical research fields and they are classified as Old World monkey, in which genome structure is characterized by gene duplications. In the present study, we investigated polymorphisms in two genes for ULBP2 molecules that are ligands for NKG2D. A total of 15 and 11 ULBP2.1 alleles and 11 and 10 ULBP2.2 alleles were identified in rhesus macaques and cynomolgus macaques, respectively. Nucleotide sequences of exons for extra cellular domain were highly polymorphic and more than 70 % were non-synonymous variations in both ULBP2.1 and ULBP2.2. In addition, phylogenetic analyses revealed that the ULBP2.2 was diverged from a branch of ULBP2.1 along with ULBP2s of higher primates. Moreover, when 3D structural models were constructed for the rhesus ULBP2 molecules, residues at presumed contact sites with NKG2D were polymorphic in ULBP2.1 and ULBP2.2 in the rhesus macaque and cynomolgus macaque, respectively. These observations suggest that amino acid replacements at the interaction sites with NKG2D might shape a specific nature of ULBP2 molecules in the Old World monkeys.
非人类灵长类动物，如恒河猴和食蟹猴，是医学研究领域的重要动物，它们被归类为旧世界猴，其基因组结构的特点是基因重复。在本研究中，我们研究了两种 ULBP2 分子的多态性，它们是 NKG2D 的配体。在恒河猴和食蟹猴中，分别鉴定出了 15 个和 11 个 ULBP2.1 等位基因，以及 11 个和 10 个 ULBP2.2 等位基因。细胞外结构域的外显子的核苷酸序列高度多态性，超过 70%是非同义变异，在 ULBP2.1 和 ULBP2.2 中均如此。此外，系统发育分析表明，ULBP2.2 是与 ULBP2.1 分支以及高等灵长类动物的 ULBP2 一起从 ULBP2 分化而来的。此外，当为恒河猴的 ULBP2 分子构建 3D 结构模型时，在恒河猴和食蟹猴的 ULBP2.1 和 ULBP2.2 中，与 NKG2D 相互作用的假定接触位点的残基是多态性的。这些观察结果表明，与 NKG2D 相互作用的位点的氨基酸替换可能塑造了旧世界猴中 ULBP2 分子的特定性质。
