tRNA editing in S. cerevisiae: Isolation and Identification of the responsible nucleotidyltransferase

酿酒酵母中的 tRNA 编辑：负责核苷酸转移酶的分离和鉴定

• 批准号: 149464258
• 负责人: Professor Dr. Mario Mörl
• 金额: --
• 依托单位: Arbeitsgruppe Biochemie und Molekularbiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/149464258?language=en
• 关键词: tRNA; editing; S.; cerevisiae; Isolation

In the mitochondrial genomes of metazoans, some tRNA genes overlap by up to six nucleotides with the neighboring downstream tRNA gene located on the same strand. In the processing of the corresponding polycistronic precursor, the downstream tRNA is released as a complete molecule, while the upstream tRNA is missing the overlapping positions and is therefore truncated at its 3’- end. An RNA editing reaction restores these missing positions and completes the tRNA by nucleotide incorporation. Interestingly, when introduced into S. cerevisiae, such a truncated tRNA is likewise restored, although this organism does not carry corresponding endogenous tRNAs as editing substrates. Obviously, yeast carries a promiscuous nucleotide incorporating activity that accepts these truncated tRNAs as substrates and adds missing nucleotides to the 3’-end. These data support the hypothesis of the evolution of RNA editing by recruitment of a pre-existing and promiscuous nucleotide inserting activity. We have designed a series of complementary approaches using screening procedures in yeast and biochemical enzyme analyses that will allow the isolation of this activity. Furthermore, substrate specificity, error rate and the ability of this activity to restore other tRNAs (tRNA repair) will be determined. The results will provide an important contribution to the discussion about the evolutionary origin of RNA editing events.

在后生动物的线粒体基因组中，一些tRNA基因与位于同一条链上的相邻下游tRNA基因重叠多达6个核苷酸。在相应的多顺反子前体的加工过程中，下游tRNA作为完整分子释放，而上游tRNA缺失重叠位置，因此在其3 '端被截短。RNA编辑反应恢复这些缺失的位置，并通过核苷酸掺入完成tRNA。有趣的是，当引入S.在酿酒酵母中，这种截短的tRNA同样被恢复，尽管这种生物体不携带相应的内源性tRNA作为编辑底物。显然，酵母携带混杂的核苷酸掺入活性，其接受这些截短的tRNA作为底物并将缺失的核苷酸添加到3 '端。这些数据支持RNA编辑通过招募预先存在的和混杂的核苷酸插入活性而进化的假设。我们已经设计了一系列的互补方法，使用筛选程序在酵母和生化酶分析，将允许这种活动的隔离。此外，还将测定底物特异性、错误率和该活性恢复其他tRNA（tRNA修复）的能力。这些结果将为RNA编辑事件的进化起源提供重要的参考。