Benne R
E.C. Slater Institute, University of Amsterdam, The Netherlands.
Eur J Biochem. 1994 Apr 1;221(1):9-23. doi: 10.1111/j.1432-1033.1994.tb18710.x.
The nucleotide sequence of mitochondrial pre-mRNAs in trypanosomes is posttranscriptionally edited by the insertion and deletion of uridylate (U) residues. In some RNAs editing is limited to small sections but in African trypanosomes, such as Trypanosoma brucei, 9 of the 18 known mitochondrial mRNAs are created by massive editing which can produce more than 50% of the coding sequence. In all cases, however, RNA editing is a key event in gene expression during which translatable RNAs are generated. The information for the editing process and possibly also the inserted Us are provided by small guide RNAs, which are encoded in both the maxicircle and minicircle components of the trypanosome mitochondrial DNA. Current models of editing are largely based on the characteristics of partially edited RNAs and on the occurrence in vivo and the possibility of synthesis in vitro of chimeric molecules in which a guide RNA is covalently linked through its 3' oligo(U) tail to an editing site in pre-mRNA. In this paper, I will review the research in this rapidly growing field and illustrate how different interpretations of the available data can lead to different views of the mechanism and the biochemistry of the editing process.
锥虫线粒体前体mRNA的核苷酸序列在转录后通过尿苷酸（U）残基的插入和缺失进行编辑。在一些RNA中，编辑仅限于小片段，但在非洲锥虫，如布氏锥虫中，18种已知的线粒体mRNA中有9种是通过大量编辑产生的，这种编辑可以产生超过50%的编码序列。然而，在所有情况下，RNA编辑都是基因表达中的关键事件，在此过程中产生可翻译的RNA。编辑过程的信息以及可能插入的U由小向导RNA提供，这些小向导RNA在锥虫线粒体DNA的大环和小环成分中都有编码。目前的编辑模型主要基于部分编辑RNA的特征、体内发生情况以及体外合成嵌合分子的可能性，在这些嵌合分子中，向导RNA通过其3'寡聚（U）尾与前体mRNA中的编辑位点共价连接。在本文中，我将综述这个快速发展领域的研究，并说明对现有数据的不同解释如何导致对编辑过程的机制和生物化学的不同看法。
