A Comprehensive Analysis of the Phylogeny, Genomic Organization and Expression of Immunoglobulin Light Chain Genes in Alligator sinensis, an Endangered Reptile Species.
A Comprehensive Analysis of the Phylogeny, Genomic Organization and Expression of Immunoglobulin Light Chain Genes in Alligator sinensis, an Endangered Reptile Species.
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濒危爬行动物扬子鳄系统发育、基因组结构及免疫球蛋白轻链基因表达的综合分析
DOI：
10.1371/journal.pone.0147704
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Ren L
中科院分区：
文献类型：
--
作者：
Wang X;Cheng G;Lu Y;Zhang C;Wu X;Han H;Zhao Y;Ren L
鳄鱼是进化上不同的爬行动物，与蜥蜴有远亲关系，被认为是鸟类的近亲。与鸟类和哺乳动物相比，鳄鱼的IG轻链研究较少。在这里，利用扬子鳄基因组细菌人工染色体（BAC）文库和现有的基因组数据，我们的特点是扬子鳄IgL基因位点的基因组组织。扬子鳄IgL有λ和κ两种亚型，与美国科罗拉多州的Anolis carolinensis相同。IGλ基因座包含6个Cλ基因，每个基因前有一个Jλ基因，（Jλ-Cλ）n上游有86个潜在功能的Vλ基因。IGκ基因座包含一个Cκ基因、6个Jκ和62个功能性Vκ。所有的VL基因被分为31个家族：19个Vλ家族和12个Vκ家族。通过对扬子鳄轻链基因在哺乳动物、鸟类、蜥蜴和青蛙中的染色体定位分析，进一步证实扬子鳄存在两种IgL亚型：IGλ和IGκ。通过分析克隆的IGλ/κ cDNA，我们鉴定了V家族在表达的Vλ和Vκ中的偏向使用模式。对重组VJ的接头的分析揭示了在表达的λ和κ序列中存在N和P核苷酸。系统发育分析的V基因揭示了V家族共享的哺乳动物，鸟类，爬行动物和非洲爪蟾，这表明这些保守的V家族是直系同源的，并已保留在IgL的进化。我们的数据表明，扬子鳄IgL基因库是高度多样性和复杂性，并提供洞察免疫球蛋白基因在脊椎动物的进化。
Crocodilians are evolutionarily distinct reptiles that are distantly related to lizards and are thought to be the closest relatives of birds. Compared with birds and mammals, few studies have investigated the Ig light chain of crocodilians. Here, employing an Alligator sinensis genomic bacterial artificial chromosome (BAC) library and available genome data, we characterized the genomic organization of the Alligator sinensis IgL gene loci. The Alligator sinensis has two IgL isotypes, λ and κ, the same as Anolis carolinensis. The Igλ locus contains 6 Cλ genes, each preceded by a Jλ gene, and 86 potentially functional Vλ genes upstream of (Jλ-Cλ)n. The Igκ locus contains a single Cκ gene, 6 Jκs and 62 functional Vκs. All VL genes are classified into a total of 31 families: 19 Vλ families and 12 Vκ families. Based on an analysis of the chromosomal location of the light chain genes among mammals, birds, lizards and frogs, the data further confirm that there are two IgL isotypes in the Alligator sinensis: Igλ and Igκ. By analyzing the cloned Igλ/κ cDNA, we identified a biased usage pattern of V families in the expressed Vλ and Vκ. An analysis of the junctions of the recombined VJ revealed the presence of N and P nucleotides in both expressed λ and κ sequences. Phylogenetic analysis of the V genes revealed V families shared by mammals, birds, reptiles and Xenopus, suggesting that these conserved V families are orthologous and have been retained during the evolution of IgL. Our data suggest that the Alligator sinensis IgL gene repertoire is highly diverse and complex and provide insight into immunoglobulin gene evolution in vertebrates.