Divergence of the Mitochondrial Genome Structure in the Apicomplexan Parasites, Babesia and Theileria
Divergence of the Mitochondrial Genome Structure in the Apicomplexan Parasites, Babesia and Theileria
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DOI：
10.1093/molbev/msp320
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发表时间：
2010-05-01
影响因子：
10.7
通讯作者：
Tanabe, Kazuyuki
中科院分区：
文献类型：
--
作者：
Hikosaka, Kenji;Watanabe, Yoh-ichi;Tanabe, Kazuyuki
来自不同系统发育群的线粒体基因组在大小、结构和组织上有很大差异。顶复门的疟原虫属（Plasmodium）是疟疾的病原体，它具有最小的mt基因组，其形式为6 kb的环状和/或串联重复的线性元件，仅编码三个蛋白质基因（cox 1、cox 3和cob）。密切相关的巴氏杆菌属和泰勒虫属也有小的mt基因组（6.6 kb），是单体线性的，其组织不同于疟原虫。为了阐明巴伯氏泰勒虫和疟原虫之间mt基因组的结构差异和进化，我们测定了来自二联巴伯氏泰勒虫B的5个新序列。caballi，B. gibsoni、东方泰勒虫（Theileria orientalis）和T.等。与先前报道的B的序列一起。bovis、牛T. annulata和T.在小孢子虫中，所有八个Babelia和Theileria mt基因组都是两端具有末端反向重复序列（TIR）的线性分子，其包含三个蛋白质编码基因（cox 1、cox 3和cob）和六个大亚基（LSU）核糖体RNA（rRNA）基因片段。蛋白质编码基因和rRNA基因片段的组织结构和转录方向在四种巴氏蝠中完全保守。相比之下，四个泰勒虫种中发生了显着的变化。虽然T. annulata和T. parva与Babelia的DNA序列几乎完全相同，但在T.东方此外，T.马基因组最大（8.2 kb），也是最分歧的，具有异常长的TIR序列，其中定位有cox 3和两个LSU rRNA基因片段。霸王马的基因组与其它物种的基因组几乎没有同线性。这些结果表明，泰勒虫mt基因组具有高度多样性，在两种泰勒虫中具有谱系特异性进化：T. orientalis和T.等。
Mitochondrial (mt) genomes from diverse phylogenetic groups vary considerably in size, structure, and organization. The genus Plasmodium, causative agent of malaria, of the phylum Apicomplexa, has the smallest mt genome in the form of a circular and/or tandemly repeated linear element of 6 kb, encoding only three protein genes (cox1, cox3, and cob). The closely related genera Babesia and Theileria also have small mt genomes (6.6 kb) that are monomeric linear with an organization distinct from Plasmodium. To elucidate the structural divergence and evolution of mt genomes between Babesia/Theileria and Plasmodium, we determined five new sequences from Babesia bigemina, B. caballi, B. gibsoni, Theileria orientalis, and T. equi. Together with previously reported sequences of B. bovis, T. annulata, and T. parva, all eight Babesia and Theileria mt genomes are linear molecules with terminal inverted repeats (TIRs) on both ends containing three protein-coding genes (cox1, cox3, and cob) and six large subunit (LSU) ribosomal RNA (rRNA) gene fragments. The organization and transcriptional direction of protein-coding genes and the rRNA gene fragments were completely conserved in the four Babesia species. In contrast, notable variation occurred in the four Theileria species. Although the genome structures of T. annulata and T. parva were nearly identical to those of Babesia, an inversion in the 3-kb central region was found in T. orientalis. Moreover, the T. equi mt genome is the largest (8.2 kb) and most divergent with unusually long TIR sequences, in which cox3 and two LSU rRNA gene fragments are located. The T. equi mt genome showed little synteny to the other species. These results suggest that the Theileria mt genome is highly diverse with lineage-specific evolution in two Theileria species: genome inversion in T. orientalis and gene-embedded long TIR in T. equi.