Structural and functional basis for protein-based eukaryotic RNA processing

 描述(申请人提供)：转移RNAs(TRNAs)是连接信使核糖核酸和蛋白质合成的重要生物适配分子。鉴于tRNAs的重要生物学作用，tRNAs的正确成熟和修饰对细胞的健康和活力是严格要求的。这在线粒体中尤为明显，线粒体tRNA基因突变是线粒体疾病的普遍原因。在细胞器基因组中，tRNAs“点缀”rRNA和蛋白质编码基因，使tRNA转录本的5‘端加工不仅对tRNA成熟至关重要，而且对之前序列的3’端加工也是必不可少的。在生命的所有领域，tRNA5‘端成熟都是由核糖核酸酶P(RNaseP)催化的。直到最近，所有已知的RNaseP酶都被认为含有催化的RNA成分。然而，在人类线粒体和拟南芥叶绿体、线粒体和细胞核中发现的仅蛋白质RNase P(PRORP)改变了这一范式。PRORP正确的tRNA成熟对人类健康至关重要；破坏tRNA5‘末端加工的PRORP及其底物的突变与包括母系遗传性高血压、线粒体肌病、MELAS和HSD10-病在内的疾病有关。我们的工作将利用生物物理、生化和细胞生物学技术来确定PRORPs的结构和机制，并开发一个体内模型系统来评估PRORPs的生理作用。这些研究将为理解一系列线粒体疾病的分子基础并最终治疗建立一个框架。总之，我们的高度跨学科的工作将提供关于高等真核生物中线粒体tRNA5‘端加工的第一个结构和机制信息。

 DESCRIPTION (provided by applicant): Transfer RNAs (tRNAs) are essential biological adaptor molecules connecting mRNA to protein synthesis. Given their important biological role, correct maturation and modification of tRNAs is strictly required for cell health and viability. Ths is particularly salient in mitochondria, where mitochondrial tRNA gene mutations are the prevalent cause of mitochondrial disease. In organellar genomes, tRNAs "punctuate" rRNA and protein coding genes, making 5' end processing of tRNA transcripts essential not only for tRNA maturation, but also for the 3' end processing of the preceding sequences. Across all domains of life, tRNA 5' end maturation is catalyzed by the essential enzyme ribonuclease P (RNase P). Until recently all known RNase P enzymes were thought to include a catalytic RNA component. However, the discovery of Protein Only RNase P (PRORP) in human mitochondria and A. thaliana chloroplasts, mitochondria, and nuclei has shifted this paradigm. Correct tRNA maturation by PRORP is essential for human health; mutations in PRORP and its substrates that disrupt tRNA 5' end processing are linked to diseases including maternally inherited essential hypertension, mitochondrial myopathy, MELAS, and HSD10- disease. Our work will use biophysical, biochemical and cell- biological techniques to determine the structure and mechanism of PRORPs, as well as develop an in vivo model system for assessing the physiological role of PRORPs. These studies will establish a framework for understanding the molecular basis of, and ultimately treating, a range of mitochondrial diseases. Together, our highly interdisciplinary work will provide the first structural and mechanistic information on mitochondrial tRNA 5' end processing in higher eukaryotes.