The complete mitochondrial genome sequence of the spider Habronattus oregonensis reveals rearranged and extremely truncated tRNAs
The complete mitochondrial genome sequence of the spider Habronattus oregonensis reveals rearranged and extremely truncated tRNAs
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DOI：
10.1093/molbev/msh096
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发表时间：
2004-05-01
影响因子：
10.7
通讯作者：
Boore, JL
中科院分区：
文献类型：
--
作者：
Masta, SE;Boore, JL
我们对蜘蛛目（节肢动物门：螯肢纲）的跳跃蜘蛛俄勒冈哈氏蛛的整个线粒体基因组进行了测序。一些不寻常的功能区分其他螯形动物和节肢动物线粒体基因组的基因组。大多数转运RNA（tRNA）基因序列的大小大大减少，不能折叠成典型的苜蓿叶形二级结构。至少有九个tRNA序列缺乏形成TPsiC臂茎配对的潜力，而是被推断为具有TV取代环。此外，在至少10个tRNA中可能编码3'氨酰基受体茎的序列似乎缺乏，因为完全配对的受体茎是不可能的，并且因为下游序列反而编码相邻基因。因此，它们似乎是已知最小的tRNA基因之一。我们假设必须存在RNA编辑机制来恢复3'氨酰基受体链，以允许tRNA发挥功能。至少有7个tRNA相对于螯合鲎（Limulus polyphemus）重排，尽管蛋白质编码基因的排列是相同的。大多数线粒体蛋白编码基因的H。oregonensis具有ATN作为起始密码子，如在节肢动物mtDNA中常见的，但细胞色素氧化酶亚基2和3基因显然使用TTG作为起始密码子。最后，许多基因序列彼此重叠并被截短。这个14，38个1 -bp的基因组是蜘蛛的第一个线粒体基因组，也是已知的最小的节肢动物线粒体基因组之一。我们认为，转录后RNA编辑可能会维持tRNA的功能，同时允许积累突变，否则将是有害的。这种机制可能允许蜘蛛线粒体基因组的最小化。
We sequenced the entire mitochondrial genome of the jumping spider Habronattus oregonensis of the arachnid order Araneae (Arthropoda: Chelicerata). A number of unusual features distinguish this genome from other chelicerate and arthropod mitochondrial genomes. Most of the transfer RNA (tRNA) gene sequences are greatly reduced in size and cannot be folded into typical cloverleaf-shaped secondary structures. At least nine of the tRNA sequences lack the potential to form TPsiC arm stem pairings and instead are inferred to have TV-replacement loops. Furthermore, sequences that Could encode the 3' aminoacyl acceptor stems in at least 10 tRNAs appear to be lacking, because fully paired acceptor stems are not possible and because the downstream sequences instead encode adjacent genes. Hence, these appear to be among the smallest known tRNA genes. We postulate that an RNA editing mechanism must exist to restore the 3' aminoacyl acceptor steins to allow the tRNAs to function. At least seven tRNAs are rearranged with respect to the chelicerate Limulus polyphemus, although the arrangement of the protein-coding genes is identical. Most mitochondrial protein-coding genes of H. oregonensis have ATN as initiation codons, as commonly found in arthropod mtDNAs, but cytochrome oxidase subunits 2 and 3 genes apparently use TTG as an initiation codon. Finally, many of the gene sequences overlap one another and are truncated. This 14,38 1 -bp genome, the first mitochondrial genome of a spider yet sequenced, is one of the smallest arthropod mitochondrial genomes known. We suggest that posttranscriptional RNA editing can likely maintain function of the tRNAs, while permitting the accumulation of mutations that Would otherwise be deleterious. Such mechanisms may have allowed for the minimization of the spider mitochondrial genome.