n nnnTranscription of mitochondrial genes in animals, fungi, andplants relies on the activity of T3/T7 phage-type RNA polymerases.Two such enzymes, RPOTm and RPOTmp, are present in the mitochondriaof eudicotyledonous plants; RPOTmp is additionally found inplastids. We have characterized the transcriptional role ofthe dual-targeted RNA polymerase in mitochondria of Arabidopsisthaliana. Examination of mitochondrial transcripts in rpoTmpmutants revealed major differences in transcript abundancesbetween wild-type and rpoTmp plants. Decreased levels of specifictranscripts were correlated with reduced abundances of the respiratorychain complexes I and IV. Altered transcript levels in rpoTmpwere found to result from gene-specific transcriptional changes,establishing that RPOTmp functions in distinct transcriptionalprocesses within mitochondria. Decreased transcription of specificgenes in rpoTmp was not associated with changes in promoterutilization; therefore, RPOTmp function is not promoter specificbut gene specific. This implies that additional gene-specificelements direct the transcription of a subset of mitochondrialgenes by RPOTmp.展开▼
机译：ABSTRACTn n
n TOP n <字体颜色= 464c53>抽象 n 介绍 n 结果 n 讨论 n 方法 n 参考文献 n n nnn动物，真菌和 植物中线粒体基因的转录r 双子叶植物的线粒体 中存在两种这样的酶RPOTm和RPOTmp；它们依赖于T3 / T7噬菌体型RNA聚合酶的活性。 RPOTmp还存在于 质体中。我们已经表征了 双靶RNA聚合酶在拟南芥（Irabidopsis thaliana ）线粒体中的转录作用。对 rpoTmp 突变体中线粒体转录本的检查显示，野生型和 rpoTmp 植物之间的转录丰度 存在主要差异。特定 转录物水平的降低与呼吸 链复合物I和IV的丰度降低相关。发现 rpoTmp 中转录本水平的改变是由于基因特异性转录变化引起的， 证实了RPOTmp在不同的转录 线粒体内的过程。 rpoTmp 中特定 基因的转录减少与启动子 利用率的变化无关；因此，RPOTmp的功能不是启动子特异性 而是基因特异性。这意味着其他特定于基因的 元素通过RPOTmp指导线粒体 基因子集的转录。展开▼
Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009 WA, Australia;
Institut für Biologie/Genetik, Humboldt-Universit?t zu Berlin, 10115 Berlin, Germany;
Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009 WA, Australia;
Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009 WA, Australia;
Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009 WA, Australia;
Centre for Computational Systems Biology, University of Western Australia, Crawley 6009 WA, Australia;
Institut für Biologie/Genetik, Humboldt-Universit?t zu Berlin, 10115 Berlin, Germany;
Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009 WA, Australia;
Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009 WA, Australia|Centre for Computational Systems Biology, University of Western Australia, Crawley 6009 WA, Australia;
Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009 WA, Australia;
