Comparative analysis of bacterial-origin genes for plant mitochondrial ribosomal proteins
Comparative analysis of bacterial-origin genes for plant mitochondrial ribosomal proteins
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DOI：
10.1093/molbev/msj080
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发表时间：
2006-03-01
影响因子：
10.7
通讯作者：
Calixte, S
中科院分区：
文献类型：
--
作者：
Bonen, L;Calixte, S
线粒体核糖体含有细菌型蛋白，反映了它们的内共生遗传，这些基因的一个子集保留在陆地植物的线粒体内。然而，由于向细胞核的迁移仍然是植物中一个持续的进化过程，因此观察到基因位置的变化。为了深入了解与成功的基因转移相关的适应事件，我们已经从完全测序的拟南芥和水稻基因组中编译了细菌来源的拟南芥型核糖体蛋白基因的数据。大约75%的这样的核定位基因编码相对于它们的大肠杆菌对应物的氨基末端延伸，并且在该集合中，只有大约30%在连接处（或附近）具有内含子，以支持上游表达/靶向信号的外显子改组型募集。我们发现，在真核生物进化早期转移到细胞核的基因，平均而言，核心核糖体蛋白序列内的内含子密度比最近转移到细胞核的基因高出两倍。大约20%的这样的内含子位于与人类直系同源物相同的位置，与它们的祖先存在一致。植物叶绿体型核糖体蛋白基因在细胞核中分布较分散，约20%的基因以多拷贝形式存在。这项研究提供了新的见解内共生细菌型基因的进化历史，已转移到细胞核。
Mitochondrial ribosomes contain bacterial-type proteins reflecting their endosymbiotic heritage, and a subset of these genes is retained within the mitochondrion in land plants. Variation in gene location is observed, however, because migration to the nucleus is still an ongoing evolutionary process in plants. To gain insights into adaptation events related to successful gene transfer, we have compiled data for bacterial-origin mitochondrial-type ribosomal protein genes from the completely sequenced Arabidopsis and rice genomes. Approximately 75% of such nuclear-located genes encode amino-terminal extensions relative to their Escherichia coli counterparts, and of that set, only about 30% have introns at (or near) the junction in Support of an exon shuffling-type recruitment of upstream expression/targeting signals. We find that genes that were transferred to the nucleus early in eukaryotic evolution have, on average, about twofold higher density of introns within the core ribosomal protein sequences than do those that moved to the nucleus more recently. About 20% of such introns are at positions identical to those in human orthologs, consistent with their ancestral presence. Plant mitochondrial-type ribosomal protein genes have dispersed chromosomal locations in the nucleus, and about 20% of them are present ill multiple unlinked copies. This Study provides new insights into the evolutionary history of endosymbiotic bacterial-type genes that have been transferred from the mitochondrion to the nucleus.