Bock R, Koop H U
Institut für Biologie III, Universität Freiburg, Germany.
EMBO J. 1997 Jun 2;16(11):3282-8. doi: 10.1093/emboj/16.11.3282.
Single nucleotides in higher plant organellar mRNAs are subject to post-transcriptional alterations by RNA editing, typically resulting in changes of the encoded protein sequence. Although some information has been acquired on the general features of the editing processes in both plastids and plant mitochondria, the mechanisms and factors involved in the selective recognition of the nucleotide to be edited are still unknown. To gain a better understanding of how an editing site is specifically selected by the organellar RNA editing machinery, we have attempted to rescue a previously generated tobacco plastid editing mutant. Using an interspecific protoplast fusion approach, we were able to restore RNA editing activity for a specific site in the psbF transcript that otherwise remained unedited. Our results suggest (i) that site-specific trans-acting factors mediate chloroplast editing site recognition and (ii) that these factors are of extraplastidic origin.
高等植物细胞器mRNA中的单核苷酸会受到RNA编辑的转录后修饰，通常会导致编码的蛋白质序列发生变化。尽管已经获得了一些关于质体和植物线粒体中编辑过程的一般特征的信息，但参与选择性识别待编辑核苷酸的机制和因素仍然未知。为了更好地理解细胞器RNA编辑机制如何特异性选择编辑位点，我们试图挽救之前产生的烟草质体编辑突变体。通过种间原生质体融合方法，我们能够恢复psbF转录本中一个特定位点的RNA编辑活性，否则该位点仍未被编辑。我们的结果表明：（i）位点特异性反式作用因子介导叶绿体编辑位点识别；（ii）这些因子起源于质体外。
