Sper-Whitis G L, Moody J L, Vaughn J C
Department of Zoology, Miami University, Oxford, OH 45056, USA.
Biochim Biophys Acta. 1996 Jul 17;1307(3):301-8. doi: 10.1016/0167-4781(96)00041-3.
Plant mitochondrial pre-mRNAs often undergo C-to-U conversions, a phenomenon termed RNA editing. The molecular source of specificity and phylogenetic depth of the editing machinery remain to be determined. We amplified coxI gene fragments via the polymerase chain reaction from a diversity of taxa within the land plants, and sequenced each. Alignment and comparison of 25 homologous coxI gene sequences with those from plant species having known RNA editing sites which restore amino acid sequence consensus was used to infer sites of C-to-U conversions. Our results, derived using the comparative approach, imply that the plant mitochondrial editing machinery extends throughout vascular plant phylogeny, and also that this phenomenon is present in every major branch of the (non-vascular) Bryophyta: liverworts (Hepaticae), hornworts (Anthocerotae), and mosses (Musci). These results have important consequences for our thoughts on the evolutionary history of the plant RNA editing process, as they imply that editing is older than was previously believed.
植物线粒体前体mRNA常常发生C到U的转变，这种现象被称为RNA编辑。编辑机制的特异性分子来源和系统发育深度仍有待确定。我们通过聚合酶链反应从陆地植物的多种分类群中扩增了细胞色素氧化酶亚基I（coxI）基因片段，并对每个片段进行了测序。将25个同源coxI基因序列与来自具有已知RNA编辑位点且能恢复氨基酸序列一致性的植物物种的序列进行比对和比较，以此推断C到U转变的位点。我们使用比较方法得出的结果表明，植物线粒体编辑机制贯穿维管植物的系统发育，而且这种现象在（非维管）苔藓植物的每个主要分支中都存在：地钱（叶苔纲）、角苔（角苔纲）和苔藓（藓纲）。这些结果对我们关于植物RNA编辑过程进化历史的认识具有重要影响，因为它们意味着编辑比之前认为的更为古老。
