Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
Cells. 2021 Feb 22;10(2):468. doi: 10.3390/cells10020468.
In there are more than 600 C-to-U RNA editing events in the mitochondria and at least 44 in the chloroplasts. Pentatricopeptide repeat (PPR) proteins provide the specificity for these reactions. They recognize RNA sequences in a partially predictable fashion via key amino acids at the fifth and last position in each PPR motif that bind to individual ribonucleotides. A combined approach of RNA-Seq, mutant complementation, electrophoresis of mitochondrial protein complexes and Western blotting allowed us to show that MEF100, a PPR protein identified in a genetic screen for mutants resistant to an inhibitor of γ -glutamylcysteine synthetase, is required for the editing of -493, -403, -698 and -356 sites in Arabidopsis mitochondria. The absence of editing in leads to a decrease in mitochondrial Complex I activity, which probably explains the physiological phenotype. Some plants have lost the requirement for MEF100 at one or more of these sites through mutations in the mitochondrial genome. We show that loss of the requirement for MEF100 editing leads to divergence in the MEF100 binding site.
在那里，线粒体中有超过 600 个 C 到 U 的 RNA 编辑事件，叶绿体中至少有 44 个。五肽重复（PPR）蛋白为这些反应提供特异性。它们通过每个 PPR 基序的第五位和最后一位的关键氨基酸以部分可预测的方式识别 RNA 序列，这些氨基酸结合到单个核苷酸上。通过 RNA-Seq、突变体互补、线粒体蛋白复合物电泳和 Western blot 的综合方法，我们表明，在针对对γ-谷氨酰半胱氨酸合成酶抑制剂具有抗性的突变体的遗传筛选中鉴定出的 PPR 蛋白 MEF100 对于拟南芥线粒体中 -493、-403、-698 和 -356 位点的编辑是必需的。在 中编辑的缺失导致线粒体复合物 I 活性降低，这可能解释了生理表型。一些植物通过线粒体基因组中的突变失去了对一个或多个这些位点的 MEF100 编辑的需求。我们表明，失去对 MEF100 编辑的需求导致 MEF100 结合位点的分歧。
