RNA PROCESSING FACTOR 3 is crucial for the accumulation of mature ccmC transcripts in mitochondria of Arabidopsis thaliana accession Columbia-猫眼课题宝

RNA 处理因子 3 对于拟南芥种质哥伦比亚线粒体中成熟 ccmC 转录物的积累至关重要

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发表时间：

2011

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作者：

S. Binder;Christian Jonietz;Joachim Forner;Tatjana M. Hildebrandt

RNA加工因子1和2是参与拟南芥不同线粒体mrna 5′加工的五肽重复（PPR）蛋白。这两个因子与育性恢复者（RESTORERS OF FERTILITY， RF）高度相似，后者是各种植物细胞质雄性不育/恢复系统的一部分。这些发现表明rf样PPR蛋白在转录后5'加工中起主导作用。为了进一步探索这组蛋白的功能，我们检测了一些携带相应PPR基因插入的T-DNA系。该筛选发现，在At1g62930 T-DNA插入系中，成熟的ccmC转录本几乎完全缺失，这种表型可以通过将完整的At1g62930基因引入突变体中来恢复。在这个核基因中的插入，我们现在称之为RNA加工因子3，也导致线粒体中CcmC蛋白的严重减少。对缺乏功能性RPF3基因的C24/ RPF3 -1 f2杂交种的分析表明，由于C24和其他品种线粒体dna中存在独特的ccmc5 ‘上游结构，该基因对成熟ccmc5 ’转录物端产生的影响较小。这些数据表明，rf样蛋白的特定功能仅与独特的mtDNA结构有关。我们的新结果进一步证实了rf样PPR蛋白在植物线粒体5 '转录末端转录后生成中的基本作用。控制可以从两个f2植株中扩增。这一结果被northern blot杂交证实，证实这些f2和C24野生型植物的成熟ccmC mrna大小相同。但northern分析也显示f2杂交种的成熟ccmC转录本水平降低。这些结果表明，在这些f2杂交种中，RPF3基因本身的功能并不需要大量成熟的C24型ccmC mRNA的产生，可能在C24中也是如此。这些观察结果表明，不同的mtDNA结构，即在ccmC上游区域，可能与RPF3阅读框的特定版本有关。因此，我们检查了RPF3编码

RNA PROCESSING FACTORS 1 and 2 are pentatricopeptide repeat (PPR) proteins involved in 5' processing of different mitochondrial mRNAs in Arabidopsis thaliana . Both factors are highly similar to RESTORERS OF FERTILITY (RF), which are part of cytoplasmic male sterility/restoration systems in various plant species. These findings suggest a predominant role of RF-like PPR proteins in posttranscriptional 5' processing. To further explore the functions of this group of proteins we examined a number of T-DNA lines carrying insertions in the corresponding PPR genes. This screening identified a nearly complete absence of mature ccmC transcripts in an At1g62930 T-DNA insertion line, a phenotype that could be restored by the introduction of the intact At1g62930 gene into the mutant. The insertion in this nuclear gene, which we now call RNA PROCESSING FACTOR 3, also leads to a severe reduction of the CcmC protein in mitochondria. The analysis of C24/ rpf3-1 F 2 hybrids lacking functional RPF3 genes revealed that this gene has less influence on the generation of the mature ccmC 5' transcript end derived from a distinct ccmC 5’ upstream configuration found in mitochondrial DNAs from C24 and other accessions. These data show that a particular function of an RF-like protein is required only in connection with a distinct mtDNA configuration. Our new results further substantiate the fundamental role of RF-like PPR proteins in the posttranscriptional generation of plant mitochondrial 5’ transcript termini. control could be amplified from two F 2 plants. This result was confirmed by a northern blot hybridization, which confirmed identical sizes of mature ccmC mRNAs in these F 2 and C24 wild-type plants. But the northern analysis also revealed a reduced level of the mature ccmC transcripts in the F 2 hybrids. These results demonstrate that the function of the RPF3 gene is per se not required for the generation of substantial amounts of the mature C24-type ccmC mRNA in these F 2 hybrids and probably also in C24. These observations suggest that a distinct mtDNA configuration, i.e. in the ccmC upstream region, might be associated with a particular version of the RPF3 reading frame. Thus we examined the RPF3 coding