Increased positive selection pressure within the CDR regions of the T cell receptor β gene in New World monkeys
Increased positive selection pressure within the CDR regions of the T cell receptor β gene in New World monkeys
复制标题
新世界猴 T 细胞受体 β 基因 CDR 内的阳性区域选择压力增加
DOI：
10.1002/ajp.20976
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发表时间：
2011
期刊：
影响因子：
2.4
通讯作者：
Suzuki R
中科院分区：
文献类型：
--
作者：
Matsutani T;Fujii Y;Kitaura K;Suzuki S;Tsuruta Y;Itoh T;Nishimoto N;Takasaki T;Kurane I;Suzuki R
由于TCR和MHC分子的长期共同进化，在TCRβ基因的结构域内积累了大量的核苷酸替换。我们之前发现，尽管只比较了有限数量的普通狨猴（Callithrix jacchus）和人类T细胞受体β变量（TRBV）序列，但在互补决定区(CDR)β中发生非同义核苷酸替换的频率高于CDRα。这一有趣的发现提出了一个问题，即CDRβ中增加的选择压力是否具有物种特异性。在本研究中，我们从普通狨猴中鉴定了21个TRBV区序列，并对人类、黑猩猩、恒河猴、棉绒猴、马氏夜猴和普通狨猴的T细胞受体α变量（TRAV）和TRBV区进行了比较序列分析。在TRAV和TRBV区域序列的框架区（FRs）中，每个位点的非同义核苷酸取代数（dN）与ds值（dN/dS）之比小于1，表明纯化选择在FRs中占主导地位，而在新世界猴中，CDRβ的dn值明显大于CDRα。此外，在人类和新世界猴之间的CDRβ中观察到dN/dS比值（dN/dS bbb1）的增加，有趣的是，在新世界猴之间，它们具有相对较近的共同祖先。此外，最大似然分析的系统发育分析提供了确凿的证据，支持CDRβ在新世界猴谱系中发生了正选择。这些结果表明，CDRβ中正向选择压力的增加在新大陆猴子中是常见的，而不是物种特异性的。这项研究为灵长类动物TCR和MHC分子的共同进化提供了一个有趣的见解。点。[j] .林业科学与技术，2011,32(3):444 - 444。©2011 Wiley‐Liss, Inc。
Because of the long‐term co‐evolution of TCR and MHC molecules, numerous nucleotide substitutions have accumulated within the domains of TCRβ genes. We previously found that nonsynonymous nucleotide substitutions occurred more frequently in complementarity determining region (CDR)β than in CDRα, even though only a limited number of common marmoset (Callithrix jacchus) and human T‐cell receptor β variable (TRBV) sequences were compared. This interesting finding raised the question of whether the increased selective pressure within CDRβ was species‐specific. In this study, we identified 21 TRBV region sequences from the common marmoset and performed comparative sequence analyses of the T‐cell receptor α variable (TRAV) and TRBV regions from human, chimpanzee, rhesus monkey, cotton‐top tamarin, Ma's night monkey, and common marmoset. The ratios of the number of nonsynonymous nucleotide substitutions per site (dN) to thedSvalues (dN/dS) were less than 1 within the framework regions (FRs) of TRAV and TRBV region sequences, suggesting that purifying selection is largely dominant within the FRs. In contrast, thedNvalues were statistically significantly greater for CDRβ than for CDRα only in New World monkeys. Also, increaseddN/dSratios (dN/dS>1) were observed within CDRβ between humans and New World monkeys and, interestingly, between New World monkeys, which share a relatively recent common ancestor. Moreover, phylogenetic analysis by maximum likelihood analysis provided firm evidence to support that positive selection occurred within CDRβ along New World monkey lineages. These results suggest that increased positive selection pressure within CDRβ is common in New World monkeys rather than being species‐specific. This study provides an intriguing insight into the co‐evolution of TCR and MHC molecules within primates. Am. J. Primatol. 73:1082–1092, 2011. © 2011 Wiley‐Liss, Inc.