Genes coding for intermediate filament proteins closely related to the hagfish “thread keratins (TK)” α and γ also exist in lamprey, teleosts and amphibians
Genes coding for intermediate filament proteins closely related to the hagfish “thread keratins (TK)” α and γ also exist in lamprey, teleosts and amphibians
复制标题
编码与盲鳗“线角蛋白（TK）”α和γ密切相关的中间丝蛋白的基因也存在于七鳃鳗、硬骨鱼和两栖动物中
DOI：
10.1016/j.yexcr.2006.01.005
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发表时间：
2006
影响因子：
3.7
通讯作者：
J. Schultess
中科院分区：
文献类型：
--
作者：
Michael Schaffeld;J. Schultess
到目前为止，“丝状角蛋白(TK)”α和γ被认为是仅限于鳗鱼的高度特化的中间丝(IF)蛋白。从七鳃鳗中，我们现在已经测序了五个新的IF蛋白，分别与TKα和TKγ密切相关。此外，我们还在硬骨鱼和两栖动物的EST和基因组数据库中检测到了相应的序列。TKα基因的结构及其推导的氨基酸序列在系统发育树中的位置清楚地支持他们被归类为II型角蛋白。编码TKγ的基因显示出IIIIF蛋白的典型结构，而它们在系统发育树中的位置倾向于与I型角蛋白有密切关系。考虑到在柳叶刀中检测到的大多数角蛋白样序列也显示出典型的IIIIF蛋白的基因结构，因此角蛋白基因(S)似乎起源于一个古老的IIIIF蛋白基因。根据EST分析，丝角蛋白在硬骨鱼和两栖动物中的表达可能特别局限于仔鱼阶段，再加上在任何现有的羊栖生物数据库中观察到的TKα和TKγ基因的缺失，表明丝角蛋白功能与水生环境中仔鱼的发育密切相关。
The “thread keratins (TK)” α and γ so far have been considered highly specialized intermediate filament (IF) proteins restricted to hagfish. From lamprey, we now have sequenced five novel IF proteins closely related to TKα and TKγ, respectively. Moreover, we have detected corresponding sequences in EST and genomic databases of teleosts and amphibians. The structure of the TKα genes and the positions of their deduced amino acid sequences in a phylogenetic tree clearly support their classification as type II keratins. The genes encoding TKγ show a structure typical for type III IF proteins, whereas their positions in phylogenetic trees favor a close relationship to the type I keratins. Considering that most keratin-like sequences detected in the lancelet also exhibit a gene structure typical for type III IF proteins, it seems likely that the keratin gene(s) originated from an ancient type III IF protein gene. According to EST analyses, the expression of the thread keratins in teleost fish and amphibians may be particularly restricted to larval stages, which, in conjunction with the observed absence of TKα and TKγ genes in any of the available Amniota databases, indicates a thread keratin function closely related to larval development in an aquatic environment.