Evolutionary conservation and diversification of Rh family genes and proteins
Evolutionary conservation and diversification of Rh family genes and proteins
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DOI：
10.1073/pnas.0507886102
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发表时间：
2005-10-25
影响因子：
11.1
通讯作者：
Peng, JB
中科院分区：
文献类型：
--
作者：
Huang, CH;Peng, JB
Rhesus（Rh）蛋白首先在人类红系细胞中鉴定，最近在其他组织中鉴定。像氨转运蛋白（NH3）一样，它们仅有的同源物，Rh蛋白具有转运蛋白特有的12个跨膜片段。许多人认为Rh和NH3蛋白运输相同的底物NH3/NH 4+，而其他人认为Rh蛋白运输CO2和NH3蛋白运输NH3。在后一种观点中，Rh和Rh是不同的生物气体通道。为了重建Rh家族的遗传关系，深入研究Rh家族与Rh家族的共存关系，我们对111个Rh基因和260个Rh基因进行了分析。虽然Rh和Rh基因在单细胞真核生物和海蜇等多种生物中被发现，但Rh基因显然出现得较晚，因为它们在原核生物中很罕见。然而，Rh基因在脊椎动物中是突出的，其中Rh基因消失。在同时具有这两种基因的生物体中，Rh基因显然迅速从Rh基因中分离出来，然后经过很长一段时间缓慢进化。功能不同的氨基酸位点聚集在跨膜段和周围的气体传导腔最近确定在大肠杆菌AmtB，在协议与Rh蛋白具有新的底物特异性。尽管基因重复和突变，Rh旁系同源群体显然都受到强烈的纯化选择，表明功能的保护。在哺乳动物红细胞中编码经典Rh蛋白的基因在非同义密码子位置处显示出比其他Rh基因更高的核苷酸取代率，这一发现表明这些蛋白在红细胞形态发生进化中可能起作用。
Rhesus (Rh) proteins were first identified in human erythroid cells and recently in other tissues. Like ammonia transporter (Amt) proteins, their only homologues, Rh proteins have the 12 transmembrane-spanning segments characteristic of transporters. Many think Rh and Amt proteins transport the same substrate, NH3/NH4+, whereas others think that Rh proteins transport CO2 and Amt proteins NH3. In the latter view, Rh and Amt are different biological gas channels. To reconstruct the phylogeny of the Rh family and study its coexistence with and relationship to Amt in depth, we analyzed 111 Rh genes and 260 Amt genes. Although Rh and Amt are found together in organisms as diverse as unicellular eukaryotes and sea squirts, Rh genes apparently arose later, because they are rare in prokaryotes. However, Rh genes are prominent in vertebrates, in which Amt genes disappear. In organisms with both types of genes, Rh had apparently diverged away from Amt rapidly and then evolved slowly over a long period. Functionally divergent amino acid sites are clustered in transmembrane segments and around the gas-conducting lumen recently identified in Escherichia coli AmtB, in agreement with Rh proteins having new substrate specificity. Despite gene duplications and mutations, the Rh paralogous groups all have apparently been subject to strong purifying selection indicating functional conservation. Genes encoding the classical Rh proteins in mammalian red cells show higher nucleotide substitution rates at nonsynonymous codon positions than other Rh genes, a finding that suggests a possible role for these proteins in red cell morphogenetic evolution.