Evolutionary diversity of vertebrate small heat shock proteins
Evolutionary diversity of vertebrate small heat shock proteins
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DOI：
10.1007/s00239-004-0013-z
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发表时间：
2004-12-01
影响因子：
3.9
通讯作者：
de Jong, WW
中科院分区：
文献类型：
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作者：
Franck, E;Madsen, O;de Jong, WW
所有脊椎动物都表达多种小型热休克蛋白 (sHsps)，它们是细胞陪伴机制的重要组成部分，并表现出惊人的多样性功能。其范围从重塑细胞骨架和抑制细胞凋亡到充当眼晶状体和精子尾部的结构蛋白。大多数信息可用于 10 种已知的哺乳动物 sHsp，正式名称为 HsB1-B10。在非哺乳动物脊椎动物中只报道了其中的三种（Hsp27/B1、αA-晶状体蛋白/B4、αB-晶状体蛋白/B5），而在青蛙和硬骨鱼中发现了明显的旁系同源物Hsp30/B11。为了重建脊椎动物中 sHsp 的进化多样性，我们在基因组、蛋白质和 EST 数据库中搜索了其他 sHsp，并对一些鸟类和两栖动物 sHsp（HspB2、Hsp30/B11）进行了测序。作为脊椎动物的外类群，尾索动物玻璃海鞘也被纳入搜索范围。现在在其他脊椎动物中也发现了七种哺乳动物 sHsp 的直系同源物。在鸟类中发现了两种新的 sHsp，名为 HspB11 和 HspB12，在硬骨鱼中发现了四种新的 sHsp，名为 HspB12-B15。来自不同脊椎动物类的直系同源 sHsp 的二级结构预测表明，功能重要的 C 端“α-晶状体蛋白结构域”的 P 夹心结构是保守的，而 N 端结构域通常具有 α-螺旋结构，尽管它们有明显的序列变异。构建的脊索动物 sHsp 树由共享内含子、插入缺失和诊断序列支持。该树区分了假定的直系同源和旁系同源关系，这将有助于各种脊椎动物 sHsp 的功能和结构比较。 15 个公认的旁系同源脊椎动物 sHsp 反映了脊椎动物进化早期广泛的基因复制时期。其中 11 个 sHsp 被分组在一个可能是脊索动物特有的进化枝中。据推测，脊索动物sHsp基因的进化过程中至少发生了13个内含子插入，而某些谱系中保留了单个古老内含子，这符合早期脊椎动物辐射之前或期间内含子大量增加的总体趋势。有趣的是出现了几个头对头定位的脊索动物 sHsp 基因对。
All vertebrates express multiple small heat shock proteins (sHsps), which are important components of the cellular chaperoning machinery and display a spectacular diversity of functions. This ranges from remodeling the cytoskeleton and inhibiting apoptosis to serving as structural proteins in eye lens and sperm tail. Most information is available for the 10 known mammalian sHsps, formally named HsB1-B10. Only three of them (Hsp27/B1, alphaA-crystallin/B4, alphaB-crystallin/B5) have been reported from nonmammalian vertebrates, while an apparent paralog, Hsp30/B11, is found in frogs and teleost fish. To reconstruct the evolutionary diversification of the sHsps in vertebrates, we searched for additional sHsps in genome, protein, and EST databases and sequenced some avian and amphibian sHsps (HspB2, Hsp30/B11). The urochordate Ciona intestinalis was included in the search, as the outgroup of vertebrates. Orthologs of seven mammalian sHsps were now found in other vertebrate classes. Two novel sHsps, named HspB11 and HspB12, were recognized in birds, and four novel sHsps, named HspB12-B15, in teleost fish. Secondary structure predictions of orthologous sHsps from different vertebrate classes indicate conservation of the P-sandwich structure of the functionally important C-terminal "alpha-crystallin domain," while the N-terminal domains generally have alpha-helical structures, despite their pronounced sequence variation. The constructed chordate sHsp tree is supported by shared introns, indels, and diagnostic sequences. The tree distinguishes putative orthologous and paralogous relationships, which will facilitate the functional and structural comparison of the various vertebrate sHsps. The 15 recognized paralogous vertebrate sHsps reflect the period of extensive gene duplications early in vertebrate evolution. Eleven of these sHsps are grouped in a clade that might be specific for chordates. It is inferred that at least 13 intron insertions have occurred during the evolution of chordate sHsp genes, while a single ancient intron is maintained in some lineages, in line with the general trend of massive intron gain before or during early vertebrate radiation. Interesting is the occurrence of several head-to-head located pairs of chordate sHsp genes.