Searching the Evolutionary Origin of Epithelial Mucus Protein Components-Mucins and FCGBP.
Searching the Evolutionary Origin of Epithelial Mucus Protein Components-Mucins and FCGBP.
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DOI：
10.1093/molbev/msw066
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发表时间：
2016-08
影响因子：
10.7
通讯作者：
Samuelsson T
中科院分区：
文献类型：
--
作者：
Lang T;Klasson S;Larsson E;Johansson ME;Hansson GC;Samuelsson T
凝胶形成的粘蛋白是大的糖基化蛋白，是覆盖上皮细胞的黏液层的基本成分。利用基于隐马尔可夫模型识别黏液蛋白的新方法，我们在后生动物中发现了大量这样的蛋白质，有助于它们的分类和进化研究。大多数脊椎动物有5-6个凝胶形成粘蛋白基因，这些基因的基因组排列在脊椎动物中很好地保守。热带爪蟾是一个例外，它拥有至少26种这种黏液。此外，我们发现最初在鸡中发现的卵泡蛋白是爬行动物、鸟类和两栖动物的特征。硬骨鱼中没有Muc6，但我们现在发现它存在于幽灵鲨等动物中，证明了它在脊椎动物进化中的早期起源。我们分析了斑马鱼、青蛙和鸡黏蛋白的公开RNA-Seq数据，从而对组织和发育特异性进行了比较。对无脊椎动物蛋白质的分析表明，凝胶形成粘蛋白类型的蛋白质也广泛分布在这一群体中。它们在刺胞目、Porifera和栉水母（栉水母）中的存在表明这些蛋白质在后生动物进化的早期就出现了。最后，我们研究了粘液中丰富的FCGBP蛋白的进化，该蛋白在结构和定位方面与凝胶形成的粘蛋白有关。我们证明了在脊椎动物中普遍存在的FCGBP具有一个保守的n端结构域。有趣的是，这个结构域也作为n端序列存在于许多细菌蛋白中。
The gel-forming mucins are large glycosylated proteins that are essential components of the mucus layers covering epithelial cells. Using novel methods of identifying mucins based on profile hidden Markov models, we have found a large number of such proteins in Metazoa, aiding in their classification and allowing evolutionary studies. Most vertebrates have 5–6 gel-forming mucin genes and the genomic arrangement of these genes is well conserved throughout vertebrates. An exception is the frog Xenopus tropicalis with an expanded repertoire of at least 26 mucins of this type. Furthermore, we found that the ovomucin protein, originally identified in chicken, is characteristic of reptiles, birds, and amphibians. Muc6 is absent in teleost fish, but we now show that it is present in animals such as ghost sharks, demonstrating an early origin in vertebrate evolution. Public RNA-Seq data were analyzed with respect to mucins in zebrafish, frog, and chicken, thus allowing comparison in regard of tissue and developmental specificity. Analyses of invertebrate proteins reveal that gel-forming-mucin type of proteins is widely distributed also in this group. Their presence in Cnidaria, Porifera, and in Ctenophora (comb jellies) shows that these proteins were present early in metazoan evolution. Finally, we examined the evolution of the FCGBP protein, abundant in mucus and related to gel-forming mucins in terms of structure and localization. We demonstrate that FCGBP, ubiquitous in vertebrates, has a conserved N-terminal domain. Interestingly, this domain is also present as an N-terminal sequence in a number of bacterial proteins.