Remarkable conservation of distinct nonclassical MHC class I lineages in divergent amphibian species.
Remarkable conservation of distinct nonclassical MHC class I lineages in divergent amphibian species.
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DOI：
10.4049/jimmunol.1001467
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发表时间：
2011-01-01
期刊：
影响因子：
--
通讯作者：
Robert J
中科院分区：
文献类型：
--
作者：
Goyos A;Sowa J;Ohta Y;Robert J
非经典MHC Ib类（Class Ib）基因是编码结构上类似于经典MHC Ia类分子但具有有限组织分布和多态性的分子的异质基因。哺乳动物的Ib类基因具有多样性，并且通常没有特征化的功能，并且由于它们的快速进化，Ib类基因的遗传学很难建立。我们已经进行了广泛的基因组，分子和Ib类基因的系统发育特征，在两个Xenopodinae两栖动物物种的不同属，从一个共同的祖先，早在灵长类动物和啮齿类动物（约6500万年）。与哺乳动物Ib类基因的不稳定性相比，我们的研究结果揭示了一个不寻常的程度的最Xenopodinae Ib类基因谱系的保护，包括一个新的单基因谱系的分歧非洲爪蟾XNC10基因和明确的志留那（非洲爪蟾）热带直向同源物，SNC10。从胸腺器官形成开始，胸腺细胞本身优先表达这种基因谱系，这与Ib类在早期T细胞发育中的专门作用一致，并表明这种功能在所有四足动物中是保守的。
Nonclassical MHC class Ib (class Ib) genes are heterogeneous genes encoding molecules that are structurally similar to classical MHC class Ia molecules but with limited tissue distribution and polymorphism. Mammalian class Ib genes have diverse and often uncharacterized functions, and because of their rapid rate of evolution, class Ib phylogeny is difficult to establish. We have conducted an extensive genomic, molecular, and phylogenetic characterization of class Ib genes in two Xenopodinae amphibian species of different genera that diverged from a common ancestor as long ago as primates and rodents (~65 million years). In contrast with the unsteadiness of mammalian class Ib genes, our results reveal an unusual degree of conservation of most Xenopodinae class Ib gene lineages, including a novel monogenic lineage represented by the divergent Xenopus laevis XNC10 gene and its unequivocal Silurana (Xenopus) tropicalis orthologue, SNC10. The preferential expression of this gene lineage by thymocytes themselves from the onset of thymic organogenesis is consistent with a specialized role of class Ib in early T cell development and suggests such a function is conserved in all tetrapods.
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DOI：
10.1073/pnas.94.26.14536
发表时间：
1997-12-23
影响因子：
11.1
作者：
Cadavid, LF;Shufflebotham, C;Watkins, DI
通讯作者：
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影响因子：
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影响因子：
64.8
作者：
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通讯作者：
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