Origin and evolution of the major histocompatibility complex class I region in eutherian mammals
Origin and evolution of the major histocompatibility complex class I region in eutherian mammals
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DOI：
10.1002/ece3.5373
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发表时间：
2019-07-01
影响因子：
2.6
通讯作者：
Zhao, Huabin
中科院分区：
文献类型：
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作者：
Abduriyim, Shamshidin;Zou, Da-Hu;Zhao, Huabin
脊椎动物的主要组织相容性复合体（MHC）基因在抵抗病原性感染中起着重要作用。为了获得新的见解MHC I类（MHCI）基因的进化和测试竞争的假设在真兽目哺乳动物的MHCI区域的起源，我们研究了9个物种的基因组组件Afrotheria，Xenarthra，和Laurasiatheria，并成功地表征了MHCI区域在6个物种。检测到以下数量的pupirates功能基因：在大象中，四个，一个，八个在扩展的I类区域，和kappa和β复制块，分别;在tenrec中，一个在kappa复制块;在四个蝙蝠物种中，一个或两个在β复制块。我们的研究结果表明，MHCI基因的κ和β复制块可能起源于真兽目哺乳动物的共同祖先。在大象、天蚕和所有四种蝙蝠中，一些MHCI基因出现在MHCI区域之外，这表明真兽目动物可能具有比以前认为的更复杂的MHCI基因组组织。蝙蝠特异性的三个或五个氨基酸的插入在MHCI α 1域中检测到的所有四个蝙蝠研究，表明蝙蝠中的病原体防御依赖于MHCI具有更宽的肽结合沟，如先前所测定的蝙蝠MHCI基因与三个氨基酸的插入显示出比其他哺乳动物更大的肽库。我们的研究增加了对真兽目MHCI基因多样性的了解，这些基因可能以特定的方式形成。
Major histocompatibility complex (MHC) genes in vertebrates are vital in defending against pathogenic infections. To gain new insights into the evolution of MHC Class I (MHCI) genes and test competing hypotheses on the origin of the MHCI region in eutherian mammals, we studied available genome assemblies of nine species in Afrotheria, Xenarthra, and Laurasiatheria, and successfully characterized the MHCI region in six species. The following numbers of putatively functional genes were detected: in the elephant, four, one, and eight in the extended class I region, and kappa and beta duplication blocks, respectively; in the tenrec, one in the kappa duplication block; and in the four bat species, one or two in the beta duplication block. Our results indicate that MHCI genes in the kappa and beta duplication blocks may have originated in the common ancestor of eutherian mammals. In the elephant, tenrec, and all four bats, some MHCI genes occurred outside the MHCI region, suggesting that eutherians may have a more complex MHCI genomic organization than previously thought. Bat-specific three- or five-amino-acid insertions were detected in the MHCI alpha 1 domain in all four bats studied, suggesting that pathogen defense in bats relies on MHCIs having a wider peptide-binding groove, as previously assayed by a bat MHCI gene with a three-amino-acid insertion showing a larger peptide repertoire than in other mammals. Our study adds to knowledge on the diversity of eutherian MHCI genes, which may have been shaped in a taxon-specific manner.