RNA Processing Factor 7 and Polynucleotide Phosphorylase Are Necessary for Processing and Stability of nad2 mRNA in Arabidopsis Mitochondria
RNA Processing Factor 7 and Polynucleotide Phosphorylase Are Necessary for Processing and Stability of nad2 mRNA in Arabidopsis Mitochondria
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DOI：
10.4161/rna.29781
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发表时间：
2014-07-01
期刊：
影响因子：
4.1
通讯作者：
Binder, Stefan
中科院分区：
文献类型：
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作者：
Stoll, Birgit;Zendler, Daniel;Binder, Stefan
植物线粒体转录物的转录后成熟需要几个步骤。其中，成熟5端的产生仍然是最神秘的过程之一。为了表征参与拟南芥（Arabidopsis thaliana）线粒体转录物5个加工的蛋白质，我们现在分析了nad 2转录物的5个成熟。基于自然的遗传变异影响5端的nad 2转录本的生态型Can-0和互补研究，我们现在确定了RNA加工因子7，它参与了成熟的nad 2 mRNA的5端的产生。RPF 7是一种相对较短的常规P类五肽重复序列蛋白，包含7个典型的P重复序列和一个短的S重复序列。Can-0中的相应等位基因编码缺少两个C-末端重复的该蛋白质的截短版本，这对于RPF 7的功能是必需的。此外，我们建立了表达靶向线粒体多核苷酸磷酸化酶（PNIPs）的人工microRNA的转基因植物，这导致PNIPs mRNA水平的大幅降低和该基因的强烈敲除。详细的定量研究5和3延长nad 2前体RNA在这些敲除植物以及在rpf 7 -1敲除突变体表明，5加工有助于稳定的线粒体转录在植物中。
Post-transcriptional maturation of plant mitochondrial transcripts requires several steps. Among these, the generation of mature 5 ends is still one of the most enigmatic processes. Toward a characterization of proteins involved in 5 processing of mitochondrial transcripts in Arabidopsis (Arabidopsis thaliana), we now analyzed 5 maturation of nad2 transcripts. Based on natural genetic variation affecting 5 ends of nad2 transcripts in ecotype Can-0 and complementation studies we now identified RNA processing factor 7, which takes part in the generation of the 5 terminus of the mature nad2 mRNA. RPF7 is a relatively short regular P-class pentatricopeptide repeat protein comprising seven canonical P repeats and a single short S repeat. The corresponding allele in Can-0 encodes a truncated version of this protein lacking two C-terminal repeats, which are essential for the function of RPF7. Furthermore we established transgenic plants expressing artifical microRNAs targeting the mitochondrial polynucleotide phosphorylase (PNPase), which results in substantial reduction of the PNPase mRNA levels and strong knockdown of this gene. Detailed quantitative studies of 5 and 3 extended nad2 precursor RNAs in these knockdown plants as well as in the rpf7-1 knockout mutant suggest that 5 processing contributes to the stability of mitochondrial transcripts in plants.