Arabidopsis 2010: Mitochondrial RNA Editing in Arabidopsis thaliana

智力优势：RNA编辑是一种改变RNA分子上特定位点遗传信息的过程。编辑已经在从病毒到动物和植物的广泛生物中被描述过。在维管植物中，细胞器转录本在合成后通过胞嘧啶-尿嘧啶（C-to-U）编辑进行修饰。尽管RNA编辑已经在一些系统中得到了广泛的研究，但在植物中，许多问题仍然存在。例如，叶绿体和线粒体编辑酶都没有发现进行实际的核苷酸改变。此外，尽管核苷酸选择性在防止rna混乱、非生产性改变方面很重要，但人们对选择要修饰的特定核苷酸的机制知之甚少。该项目旨在通过鉴定参与线粒体编辑的蛋白质来加深对植物RNA编辑的理解。在之前的工作中，拟南芥的自然变异与遗传分析相结合，可以在两个拟南芥品系中定位控制特定C靶点编辑程度差异的数量性状位点（qtl）。QTL区间的候选编辑基因将通过病毒诱导的基因沉默（VIGS）测试是否可能参与特定C靶标的编辑。编辑基因中的敲除突变体将通过VIGS筛选从公开的突变体集合中寻找。突变和正常植物的免疫沉淀或亲和标记实验将用于鉴定执行线粒体RNA编辑的分子机器的组成部分。更广泛的影响：线粒体是植物中必不可少的细胞器，对能量转导至关重要。植物线粒体基因的表达受到RNA编辑过程的深刻影响，该过程修改了基因组中编码的多达500个Cs。识别负责编码执行RNA编辑的蛋白质的核基因对于我们理解线粒体生物发生至关重要。该项目将在未来三年内为8-12名本科生提供研究经验，其中包括参加NSF REU项目的少数族裔学生。

Intellectual Merit: RNA editing is a process that alters the genetic information at specific sites on RNA molecules. Editing has been described in a wide range of organisms from viruses to animals and plants. In vascular plants, organelle transcripts are modified after synthesis by cytosine-to-uracil (C-to-U) editing. Although RNA editing has been studied extensively in some systems, in plants, many questions still remain. For example, neither the chloroplast nor mitochondrial editing enzyme that performs the actual nucleotide alteration has been discovered. Also, despite the importance of nucleotide selectivity in preventing chaotic, unproductive alteration of RNAs, little is known about the mechanisms responsible for selecting specific nucleotides to be modified. This project seeks to deepen understanding of plant RNA editing by identifying proteins that are involved in mitochondrial editing. In prior work, natural variation in Arabidopsis combined with genetic analysis allowed the mapping of quantitative trait loci (QTLs) that control differential editing extent at specific C targets of editing in two Arabidopsis lines. Candidate editing genes in the QTL intervals will be tested for their possible involvement in editing of specific C targets by virus-induced gene silencing (VIGS). Knock-out mutants in editing genes identified by the VIGS screen will be sought from publicly available mutant collections. Immunoprecipitation or affinity tagging experiments with mutant and normal plants will be used to identify components of the molecular machine that performs mitochondrial RNA editing.Broader Impact: Mitochondria are essential organelles in plants that are critical for energy transduction. Plant mitochondrial gene expression is profoundly affected by the RNA editing process, which modifies as many as 500 Cs encoded in the genome. Identifying the nuclear genes that are responsible for encoding proteins that perform RNA editing is essential to our understanding of mitochondrial biogenesis. This project will provide research experiences for 8-12 undergraduates over the next three years, including underrepresented minority students participating in an NSF REU program.