Evolution of the arginine kinase gene family
Evolution of the arginine kinase gene family
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DOI：
10.1016/j.cbd.2005.10.007
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发表时间：
2006-06-01
影响因子：
3
通讯作者：
Suzuki, Tomohiko
中科院分区：
文献类型：
--
作者：
Uda, Kouji;Fujimoto, Naka;Suzuki, Tomohiko
精氨酸激酶（AK）催化磷酸盐从MgATP可逆地转移到精氨酸，产生磷酸精氨酸和MgADP，广泛分布于无脊椎动物中，也存在于某些原生动物中。通常，这些蛋白质被发现作为靶向细胞质的单体，但已经观察到真正的二聚体和连续的二聚体AK以及线粒体AK活性。在本研究中，我们已经获得了AKs的基因序列，从两个远亲的软体动物-鹦鹉螺pompilius和双壳牡蛎。这些新数据与从EST和基因组测序计划数据库中提取的可用基因结构数据（外显子/内含子组织）相结合。这些数据，包括23个序列和基因结构的原生动物，刺胞动物，扁形动物，软体动物，节肢动物和线虫，提供了很大的洞察AK家族的进化和分歧。序列和系统发育分析清楚地表明，AK是同源的，来自一些共同的祖先。然而，AK基因组织是高度分化和可变的。软体动物AK基因通常具有高度保守的六个外显子/五个内含子的组织，其结构与扁形动物曼氏血吸虫的结构非常相似。节肢动物和线虫AK基因具有较少的内含子，而刺胞动物和原生动物的基因与其他AK基因相比各自显示独特的外显子/内含子组织。AK基因的非保守性与在同源酶肌酸激酶（CK）中看到的相对高度保守的内含子位置形成鲜明对比。本研究结果还表明，基因重复和随后的融合事件形成不寻常的两个域AKs独立地发生至少四次，因为这些连续的二聚体存在于原生动物，刺胞动物，扁形动物和软体动物。对氨基酸序列的详细分析表明，两种AK（分别来自果蝇和小杆线虫）具有似乎是N-末端线粒体靶向序列的序列，为真正的线粒体AK基因提供了第一个证据。AK基因家族是一个古老的家族，该家族经历了相当大的分化以及多次重复和融合事件。(c)2005年爱思唯尔公司All rights reserved.
Arginine kinase (AK), catalyzing the reversible transfer of phosphate from MgATP to arginine yielding phosphoarginine and MgADP, is widely distributed throughout the invertebrates and is also present in certain protozoa. Typically, these proteins are found as monomers targeted to the cytoplasm, but true dimeric and contiguous dimeric AKs as well as mitochondrial AK activities have been observed. In the present study, we have obtained the sequences of the genes for AKs from two distantly related molluscs-the cephalopod Nautilus pompilius and the bivalve Crassostrea gigas. These new data were combined with available gene structure data (exon/intron organization) extracted from EST and genome sequencing project databases. These data, comprised of 23 sequences and gene structures from Protozoa, Cnidaria, Platyhelminthes, Mollusca, Arthropoda and Nematoda, provide great insight into the evolution and divergence of the AK family. Sequence and phylogenetic analyses clearly show that the AKs are homologous having arisen from some common ancestor. However, AK gene organization is highly divergent and variable. Molluscan AK genes typically have a highly conserved six-exon/five-intron organization, a structure that is very similar to that of the platyhelminth Schistosoma mansoni Arthropod and nematode AK genes have fewer introns, while the cnidarian and protozoan genes each display unique exon/intron organization when compared to the other AK genes. The non-conservative nature of the AK genes is in sharp contrast to the relatively high degree of conservation of intron positions seen in a homologous enzyme creatine kinase (CK). The present results also show that gene duplication and subsequent fusion events forming unusual two-domain AKs occurred independently at least four times as these contiguous dimers are present in Protozoa, Cnidaria, Platyhelminthes and Mollusca. Detailed analyses of the amino acid sequences indicate that two AKs (one each from Drosophila and Caenorhabditis) have what appear to be N-terminal mitochondrial targeting sequences, providing the first evidence for true mitochondrial AK genes. The AK gene family is ancient and the lineage has undergone considerable divergence as well as multiple duplication and fusion events. (c) 2005 Elsevier Inc. All rights reserved.