Identification of nuclear encoded genes involved in 5' end processing of mitochondrial mRNA in Arabidopsis thaliana

在拟建的项目中，参与植物线粒体转录本5端加工的基因将通过正向遗传方法进行鉴定。本项目的基础是对拟南芥三种不同生态型的主要线粒体mRNA末端进行分析。该研究揭示了线粒体基因nad9、nad4、ccmB和rpl5的生态型特异性5 ' mRNA多态性。对相应的F1杂交种的分析将这些多态性分配到不同的核编码基因上。现在，拟南芥自然发生的遗传变异将用于这些编码线粒体RNA加工因子（RPF）的核基因的图谱克隆。这种极具价值的自然变异系统是目前唯一可以替代非常有限的细胞质雄性不育/恢复生殖系统的系统，这在拟南芥中是没有发现的。为了进一步确定生态型特异性变异，将同时开始对来自编码复合体I亚基（nad基因）的基因的5 '加工进行全面的描述性分析。这项研究将产生更多关于加工事件和RNA中间体的明确信息。

In the proposed project genes involved in 5 end processing of plant mitochondrial transcripts will be identified by a forward genetic approach. The groundwork for this project is the analysis of major mitochondrial mRNA ends in three different ecotypes of Arabidopsis thaliana. This investigation revealed ecotype-specific 5’ mRNA polymorphisms for the mitochondrial genes nad9, nad4, ccmB and rpl5. Analysis of corresponding F1 hybrids assigned these polymorphisms to different nuclear encoded genes. Now the naturally occurring genetic variation in the model species A. thaliana will be used for map-based cloning of these nuclear genes encoding mitochondrial RNA processing factors (RPF). The highly valuable system of natural variation is presently the sole alternative to the very limited cytoplasmic male sterility/restorer of fertility system, which is not found for A. thaliana. To identify further ecotype-specific variations a comprehensive descriptive analysis of 5’ processing of mRNA derived from gene encoding subunits of complex I (nad genes) will be initiated in parallel. This investigation will yield more definite information about the processing events and of RNA intermediates.