Long-lived dichotomous lineages of the proteasome subunit beta type 8 (PSMB8) gene surviving more than 500 million years as alleles or paralogs.
Long-lived dichotomous lineages of the proteasome subunit beta type 8 (PSMB8) gene surviving more than 500 million years as alleles or paralogs.
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蛋白酶体 8 型亚基 (PSMB8) 基因的长寿二分谱系作为等位基因或旁系同源物存活了 5 亿多年。
DOI：
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发表时间：
2012
影响因子：
10.7
通讯作者：
M. Nonaka
中科院分区：
文献类型：
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作者：
Kentaro Tsukamoto;F. Miura;Naoko T Fujito;G. Yoshizaki;M. Nonaka
在进化的时间尺度上，多态等位基因被认为具有很短的寿命，即使在长期的平衡选择下也最多持续数千万年。在这里，我们报告高度分歧的跨物种二型的蛋白酶体亚基β型8（PSMB 8）基因，它编码的免疫蛋白酶体的催化亚基负责产生的主要组织相容性复合体（MHC）I类分子的肽，在较低的硬骨鱼类，包括鲤形目（斑马鱼和泥鳅）和鲑形目（鳟鱼和鲑鱼），其最后的共同祖先的日期为300马。此外，系统发育分析表明，这些二态等位基因共享的血统与两个鲨鱼旁系同源基因，这表明这两个血统已保持超过500我无论是作为等位基因或旁系同源，和等位基因和旁系同源之间的转换至少发生一次在脊椎动物进化。PSMB 8A和PSMB 8F两个谱系显示A（31）F取代可能会影响它们的切割特异性，而PSMB 8A谱系已被所有分析的有颌脊椎动物保留，PSMB 8F谱系已被大多数有颌脊椎动物丢失，除了软骨鱼和基底硬骨鱼。然而，PSMB8F谱系的可能功能等同物在两栖动物爪蟾和硬骨鱼Oryzias物种的脊椎动物进化过程中至少两次作为PSMB8A谱系内的等位基因而复活。PSMB 8多态性通过等位基因和旁系同源物之间的二态性和转换的长期持续、丢失和恢复的动态演变意味着该基因的功能多态性存在强选择压力。
On an evolutionary time scale, polymorphic alleles are believed to have a short life, persisting at most tens of millions of years even under long-term balancing selection. Here, we report highly diverged trans-species dimorphism of the proteasome subunit beta type 8 (PSMB8) gene, which encodes a catalytic subunit of the immunoproteasome responsible for the generation of peptides presented by major histocompatibility complex (MHC) class I molecules, in lower teleosts including Cypriniformes (zebrafish and loach) and Salmoniformes (trout and salmon), whose last common ancestor dates to 300 Ma. Moreover, phylogenetic analyses indicated that these dimorphic alleles share lineages with two shark paralogous genes, suggesting that these two lineages have been maintained for more than 500 My either as alleles or as paralogs, and that conversion between alleles and paralogs has occurred at least once during vertebrate evolution. Two lineages termed PSMB8A and PSMB8F show an A(31)F substitution that would probably affect their cleaving specificity, and whereas the PSMB8A lineage has been retained by all analyzed jawed vertebrates, the PSMB8F lineage has been lost by most jawed vertebrates except for cartilaginous fish and basal teleosts. However, a possible functional equivalent of the PSMB8F lineage has been revived as alleles within the PSMB8A lineage at least twice during vertebrate evolution in the amphibian Xenopus and teleostean Oryzias species. Dynamic evolution of the PSMB8 polymorphism through long-term persistence, loss, and regaining of dimorphism and conversion between alleles and paralogs implies the presence of strong selective pressure for functional polymorphism of this gene.
影响因子：
9.8
作者：
Agarwal, Anil K.;Xing, Chao;Garg, Abhimanyu
通讯作者：
Garg, Abhimanyu