Widespread and extensive editing of mitochondrial mRNAS in dinoflagellates
Widespread and extensive editing of mitochondrial mRNAS in dinoflagellates
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DOI：
10.1016/s0022-2836(02)00468-0
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发表时间：
2002-07-19
影响因子：
5.6
通讯作者：
Gray, MW
中科院分区：
文献类型：
--
作者：
Lin, SJ;Zhang, HA;Gray, MW
基于对两个线粒体 DNA 编码基因 cox1（细胞色素氧化酶亚基 1）和 cob（脱辅基细胞色素 b）确定的基因组和相应 cDNA 序列的比较，我们报告了甲藻物种 Pfiesteria piscicida、Prorocentrum minimise 和 Crypthecodinium cohnii 中线粒体 mRNA 的广泛替代编辑的证据。在cox1 mRNA中，我们在39个密码子的40个位点上识别出72个替换，而在cob mRNA中，我们在48个密码子的51个位点上推断出86个编辑事件。编辑发生在不同的簇中，变化类似于总序列的 2%，主要发生在密码子的第一个和第二个位置，并且主要涉及（但不限于）A - G (47%)、U --> C (23%) 和 C --> U (17%) 替换。在 158 个案例中，除了 4 个案例外，其他所有案例中的编辑都改变了指定氨基酸的特性。在 21 (cox1) 和 26 (cob) 位点，在至少两个所研究的物种的相同位置观察到相同的核苷酸变化。在大约三分之一的位点，编辑会导致氨基酸发生变化，从而增加甲藻 Cox1 和 Cob 序列及其在其他生物体中的同源物之间的相似性；据推测，在这些站点进行编辑具有特殊的功能意义。总体而言，大约一半的编辑事件维持或增加了甲藻蛋白序列与其非甲藻同源物之间的相似性，而另外三分之一的改变是“甲藻特异性的”（即它们涉及在给定位置的至少两种甲藻物种中选择性保守的氨基酸残基的改变）。推断的编辑的性质、模式和系统发育分布意味着，要么不止一种类型的先前描述的编辑过程在甲藻线粒体中的给定转录物上进行，要么在甲藻谱系中进化出一种机械上独特的线粒体 mRNA 编辑类型。 (C) 2002 Elsevier Science Ltd. 保留所有权利。
We report evidence of extensive substitutional editing of mitochondrial, mRNAs in the dinoflagellate species Pfiesteria piscicida, Prorocentrum minimum and Crypthecodinium cohnii, based on a comparison of genomic and corresponding cDNA sequences determined for two mitochondrial DNA-encoded genes, cox1 (cytochrome oxidase subunit 1) and cob (apocytochrome b). In the cox1 mRNA, we identify 72 substitutions at 40 sites in 39 codons, whereas in cob mRNA, we infer 86 editing events at 51 sites in 48 codons. Editing, which takes place in distinct clusters, changes similar to2% of the total sequence, occurs predominantly at first and second positions of codons, and involves mostly (but not exclusively) A - G (47%), U --> C (23%) and C --> U (17%) substitutions. In all but four of the, 158 cases, editing changes the identity of the specified amino acid. At 21 (cox1) and 26 (cob) sites, the same nucleotide change is observed at the same position in at least two of the species investigated. At about one-third of the sites, editing results in an amino acid change that increases similarity between the dinoflagellate Cox1 and Cob sequences and their homologs in other organisms; presumably editing at these sites is of particular functional significance. Overall, about half of the editing events either maintain or increase similarity between the dinoflagellate protein sequences and their non-dinoflagellate homologs, while a further one-third of the alterations are "dinoflagellate-specific" (i.e. they involve a change to an amino acid residue selectively conserved in at least two of the dinoflagellate species at a given position). The nature, pattern and phylogenetic distribution of the inferred edits implies either that more than one type of previously described editing process operates on a given transcript in dinoflagellate mitochondria, or that a mechanistically unique type of mitochondrial mRNA editing has evolved within the dinoflagellate lineage. (C) 2002 Elsevier Science Ltd. All rights reserved.