Hameed Muhammad Waqar, Juszczak Ilona, Bock Ralph, van Dongen Joost Thomas
Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany.
Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270 Pakistan.
Plant Methods. 2017 Dec 13;13:112. doi: 10.1186/s13007-017-0257-4. eCollection 2017.
To investigate translational regulation of gene expression in plant mitochondria, a mitochondrial polysome isolation protocol was established for tobacco to investigate polysomal mRNA loading as a proxy for translational activity. Furthermore, we developed an oligonucleotide based microarray platform to determine the level of and mitochondrial mRNA.
Microarray analysis of free and polysomal mRNAs was used to characterize differences in the levels of free transcripts and ribosome-bound mRNAs in various organs of tobacco plants. We have observed higher mitochondrial transcript levels in young leaves, flowers and floral buds as compared to fully expanded leaves and roots. A similar pattern of abundance was observed for ribosome-bound mitochondrial mRNAs in these tissues. However, the accumulation of the mitochondrial protein COX2 was found to be inversely related to that of its ribosome-bound mRNA.
Our results indicate that the association of mitochondrial mRNAs to ribosomes is largely determined by the total transcript level of a gene. However, at least for we demonstrated that the level of ribosome-bound mRNA is not reflected by the amount of COX2 protein.
为了研究植物线粒体中基因表达的翻译调控，我们建立了一种用于烟草的线粒体多核糖体分离方案，以研究多核糖体mRNA负载情况，作为翻译活性的一个指标。此外，我们开发了一种基于寡核苷酸的微阵列平台，以确定线粒体mRNA的水平。
利用对游离和多核糖体mRNA的微阵列分析，来表征烟草植株不同器官中游离转录本水平与核糖体结合mRNA水平的差异。我们观察到，与完全展开的叶片和根相比，幼叶、花和花芽中的线粒体转录本水平更高。在这些组织中，核糖体结合的线粒体mRNA也呈现出类似的丰度模式。然而，发现线粒体蛋白COX2的积累与其核糖体结合mRNA的积累呈负相关。
我们的结果表明，线粒体mRNA与核糖体的结合在很大程度上由基因的总转录水平决定。然而，至少对于COX2而言，我们证明核糖体结合mRNA的水平并未反映在COX2蛋白的量上。
