Lateral transfer of a lectin-like antifreeze protein gene in fishes.
Lateral transfer of a lectin-like antifreeze protein gene in fishes.
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DOI：
10.1371/journal.pone.0002616
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发表时间：
2008-07-09
期刊：
影响因子：
3.7
通讯作者：
Davies PL
中科院分区：
文献类型：
--
作者：
Graham LA;Lougheed SC;Ewart KV;Davies PL
生活在冰冷海水中的鱼类通常会受到内源性抗冻蛋白（AFP）的保护，这些蛋白与冰晶结合并阻止它们生长。五种高度多样化的AFP类型在遗传学上完全不同的鱼类物种中的分散分布令人困惑。在密切相关的物种中出现完全不同的AFP归因于这些蛋白质的快速，独立的进化，以应对过去2000万年内海平面冰川引起的自然选择。在至少一种情况下，相同类型的简单重复AFP通过趋同进化独立地起源于两个遥远的物种。但是，孤立发生的三个非常相似的II型AFP在三个远亲物种（鲱鱼，胡瓜鱼和海乌鸦）不能用这种机制来解释。这些球状凝集素样AFP具有独特的二硫键模式，其氨基酸序列具有高达85%的同一性，其基因中具有更高同一性的区域。对现有数据库的彻底搜索未能在任何其他物种中找到具有大于40%氨基酸序列同一性的同源物。与这一结果相一致，基因组Southern印迹显示凝集素样AFP基因在所有其他鱼类中均不存在。内含子和外显子序列的显着保守性，缺乏进化距离和突变率之间的相关性，以及沉默与非沉默密码子变化的模式，使得AFP基因不太可能预先存在，但从硬骨鱼辐射的大多数分支中丢失。相反，我们建议，横向基因转移导致在鲱鱼，胡瓜鱼和海乌鸦的II型AFP的发生，并允许这些物种生存在一个致命的生态位。
Fishes living in icy seawater are usually protected from freezing by endogenous antifreeze proteins (AFPs) that bind to ice crystals and stop them from growing. The scattered distribution of five highly diverse AFP types across phylogenetically disparate fish species is puzzling. The appearance of radically different AFPs in closely related species has been attributed to the rapid, independent evolution of these proteins in response to natural selection caused by sea level glaciations within the last 20 million years. In at least one instance the same type of simple repetitive AFP has independently originated in two distant species by convergent evolution. But, the isolated occurrence of three very similar type II AFPs in three distantly related species (herring, smelt and sea raven) cannot be explained by this mechanism. These globular, lectin-like AFPs have a unique disulfide-bonding pattern, and share up to 85% identity in their amino acid sequences, with regions of even higher identity in their genes. A thorough search of current databases failed to find a homolog in any other species with greater than 40% amino acid sequence identity. Consistent with this result, genomic Southern blots showed the lectin-like AFP gene was absent from all other fish species tested. The remarkable conservation of both intron and exon sequences, the lack of correlation between evolutionary distance and mutation rate, and the pattern of silent vs non-silent codon changes make it unlikely that the gene for this AFP pre-existed but was lost from most branches of the teleost radiation. We propose instead that lateral gene transfer has resulted in the occurrence of the type II AFPs in herring, smelt and sea raven and allowed these species to survive in an otherwise lethal niche.
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DOI：
10.1073/pnas.94.8.3817
发表时间：
1997-04-15
影响因子：
11.1
作者：
Chen, LB;DeVries, AL;Cheng, CHC
通讯作者：
Cheng, CHC
影响因子：
4
作者：
Cheng, CHC
通讯作者：
Cheng, CHC
影响因子：
64.8
作者：
HARTLEY, BS;BROWN, JR;SMILLIE, LB
通讯作者：
SMILLIE, LB
影响因子：
64.8
作者：
Kasahara, Masahiro;Naruse, Kiyoshi;Kohara, Yuji
通讯作者：
Kohara, Yuji
影响因子：
4.8
作者：
Ewart, KV;Yang, DSC;Hew, CL
通讯作者：
Hew, CL