Hyaloraphidium curvatum:: A linear mitochondrial genome, tRNA editing, and an evolutionary link to lower fungi
Hyaloraphidium curvatum:: A linear mitochondrial genome, tRNA editing, and an evolutionary link to lower fungi
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DOI：
10.1093/oxfordjournals.molbev.a004084
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发表时间：
2002-03-01
影响因子：
10.7
通讯作者：
Lang, BF
中科院分区：
文献类型：
--
作者：
Forget, L;Ustinova, J;Lang, BF
我们已经测序的线粒体DNA（mtDNA）的Hyaloraphidium curvatum，以前被归类为一个无色的绿色真菌，但现在被认为是一个较低的真菌分子数据的基础上。线粒体染色体长度为29.97 kbp，是一个单体的线性分子，两端有相同的反向重复序列（1.43 kbp），这是线粒体中罕见的基因组结构。该基因组仅编码14种已知的线粒体蛋白质。7个tRNA、大亚基rRNA和小亚基rRNA（SSU rRNA）和3个ORF。SSU rRNA由两个基因片段编码，位于mtDNA上相距8 kbp处。杂乱和片段化的线粒体rRNA在绿色藻类和蜂窝原生生物中是已知的，但在真菌中是前所未有的。蛋白质基因编码脱辅基细胞色素B：细胞色素氧化酶1。2和3。NADH脱氢酶1、2、3、4、4L、5和6以及ATP合酶6。8和9亚基，这些基因中有几个被组织在操纵子样簇中。由7个线粒体编码的tRNA组成的组不足以识别线粒体蛋白质基因中存在的所有密码子。当考虑到明显的密码子偏好，至少有16个核编码的tRNA被假定为输入线粒体。预测的7个tRNA-encoded tRNA序列中有3个在受体茎的前3个位置携带错配。这强烈表明，这些tRNA是由一种机制punctatus和根足类变形虫的编辑类似于一个在真菌Spizellomyces我们的系统发育分析证实了压倒性的支持，H curvatum是一些壶菌纲真菌，特别是与Monoblepharidales。
We have sequenced the mitochondrial DNA (mtDNA) of Hyaloraphidium curvatum, an organism previously classified as a colorless green alga but now recognized as a lower fungus based on molecular data. The 29.97-kbp mitochondrial chromosome is maintained Lis a monomeric, linear molecule with identical, inverted repeats (1.43 kbp) at both ends, a rare genome architecture in mitochondria. The genome encodes only 14 known mitochondrial proteins. 7 tRNAs, the large subunit rRNA and small subunit rRNA (SSU rRNA), and 3 ORFs. The SSU rRNA is encoded in two gene pieces, that are located 8 kbp apart on the mtDNA. Scrambled and fragmented mitochondrial rRNAs are well known from green algae and alveolate protists hut are unprecedented in fungi. Protein genes code for apocytochrome b: cytochrome oxidase 1. 2, and 3. NADH dehydrogenase 1, 2, 3 4, 4L, 5, and 6, and ATP synthase 6. 8, and 9 subunits, and several of these genes are organized in operon-like clusters. The set of seven mitochondrially encoded tRNAs is insufficient to recognize all codons that Occur in the mitochondrial protein genes. When taking into account the pronounced codon bias, at least 16 nuclear-encoded tRNAs are assumed to tic imported into the mitochondria. Three of the seven predicted mitochondria-encoded tRNA sequences carry mispairings in the first three positions of the acceptor stem. This strongly suggests that these tRNAs are edited by a mechanism punctatus and the rhizopod amoeba Acanthamoeba castellanii similar to the one seen in the fungus Spizellomyces an Our phylogenetic analysis confirms with overwhelming support that H curvatum is a number of the chytridiomycete fungi, specifically related to the Monoblepharidales.