Choury David, Araya Alejandro
Laboratoire de Réplication et Expression des Génomes Eucaryotes et Rétroviraux, UMR 5097, Centre National de la Recherche Scientifique and Université Victor, Segalen Bordeaux II, 146, Bordeaux Cedex, France.
Curr Genet. 2006 Dec;50(6):405-16. doi: 10.1007/s00294-006-0100-3. Epub 2006 Oct 11.
RNA editing is a process that modifies the information content of mitochondrial messenger RNAs in flowering plants changing specific cytosine residues into uridine. To gain insight into editing site recognition, we used electroporation to introduce engineered wheat (Triticum aestivum) or potato (Solanum tuberosum) mitochondrial cox2 genes, and an atp9-containing chimeric gene, into non-cognate mitochondria, and observed the efficiency of editing in these contexts. Both wheat and potato mitochondria were able to express "foreign" constructs, and their products were properly spliced. Seventeen and twelve editing sites are present in the coding regions of wheat and potato cox2 transcripts, respectively. Eight are common to both plants, whereas nine are specific to wheat, and four to potato. An analogous situation is found for the atp9 mRNA coding regions from these species. We found that both mitochondria were able to recognize sites that are already present as T at the genomic level, making RNA editing unnecessary for that specific residue in the cognate organelle. Our results demonstrate that non-cognate mitochondria are able to edit residues that are not edited in their own transcripts, and support the hypothesis that the same trans-acting factor may recognize several editing sites.
RNA编辑是一个改变开花植物线粒体信使RNA信息内容的过程，它将特定的胞嘧啶残基转变为尿苷。为了深入了解编辑位点识别机制，我们利用电穿孔技术将经过改造的小麦（普通小麦）或马铃薯（马铃薯）线粒体cox2基因以及一个含atp9的嵌合基因导入非同源线粒体中，并观察这些情况下的编辑效率。小麦和马铃薯的线粒体均能够表达“外源”构建体，且其产物能够正确剪接。小麦和马铃薯cox2转录本的编码区分别存在17个和12个编辑位点。其中8个位点在两种植物中都有，9个位点是小麦特有的，4个位点是马铃薯特有的。对于这些物种的atp9 mRNA编码区也发现了类似情况。我们发现，两种线粒体都能够识别在基因组水平上已经为T的位点，使得同源细胞器中该特定残基无需进行RNA编辑。我们的结果表明，非同源线粒体能够编辑其自身转录本中未编辑的残基，并支持同一反式作用因子可能识别多个编辑位点的假说。
