Mechanism of tRNA Import Into Trypanosome Mitochondria

tRNA 导入锥虫线粒体的机制

• 批准号: 7188655
• 负责人: STEPHEN L HAJDUK
• 金额: $ 34.96万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7188655
• 关键词: Affinity Chromatography; African; Binding; Biological Assay; Cell Fractionation; Cell Line; Cell Nucleus; Cells; Complex; Conserved Sequence; Coupled; Cytosol; Development; Elements; Eukaryotic Cell; Gel; Genes; Genetic Transcription; Genome; Goals; Human; In Vitro; Indium; Kinetics; Label; Localized; Metabolic; Mitochondria; Mitochondrial RNA; Modeling; Mutate; Mutation; Nuclear; Numbers; Organelles; Organism; Pathway interactions; Production; Protein Binding; Protein Biosynthesis; Protein Import; Proteins; Proteomics; RNA; RNA Interference; Rate; Relative (related person); Research Personnel; Reverse Transcriptase Polymerase Chain Reaction; Ribosomes; Role; Site; Structure; System; Therapeutic; Transcription Initiation; Transcription Initiation Site; Transfection; Transfer RNA; Translations; Trypanosoma; Work; base; crosslink; defined contribution; in vivo; knockout gene; mitochondrial membrane; novel; programs; promoter; protein function; research study; tRNA Biosynthesis Pathway; trafficking; translation factor

DESCRIPTION (provided by the applicant): Mitochondria are essential organelles found in most eukaryotic cells and provide for diverse metabolic functions. Fully active mitochondria require proteins and RNAs encoded both by the mitochondrial and nuclear genomes. In humans, at least 600 nuclear encoded proteins are imported into mitochondria and another 13 proteins are encoded by mitochondrial genes. The translation of this limited number of mitochondria-encoded proteins requires mitochondrial ribosomes, translation factors and transfer RNAs. Recent studies, of evolutionary diverse organisms, have shown that some or all of the mitochondrial tRNAs can be nuclear-encoded and must be imported into the mitochondria. In trypanosomes, all mitochondrial tRNAs are nuclear encoded and most are localized to both the mitochondrion and cytosol. While remarkable progress has been made in the elucidation of the mechanism of protein import into fungal and mammalian mitochondria, little is known about the mechanism of mitochondrial RNA import. The overall goal of this proposal is to dissect the pathway of tRNA biosynthesis and trafficking in African trypanosomes. To accomplish this goal the following specific aims are proposed. In Specific Aim I, the biosynthetic pathway for trypanosome tRNAs will be investigated by in vitro transcription and kinetic analysis of tRNA trafficking in intact cells. In Specific Aim II, the role of specific sequence and/or structural motifs in tRNA export from the nucleus and import into the mitochondria will be determined. Finally, in Specific Aim III, trypanosome proteins that interact with precursor and mature tRNAs to influence tRNA trafficking and ultimately mitochondrial import will be identified. Trypanosomes offer an attractive model to study tRNA trafficking pathways since both in vitro and in vivo systems have recently been developed to study both tRNA synthesis and mitochondrial import. In addition, mitochondrial tRNA import may have therapeutic potential since, in contrast to trypanosomes, all mammalian mitochondrial tRNAs are encoded by mitochondrial genes.

描述（由申请人提供）：线粒体是在大多数真核细胞中发现的必不可少的细胞器，并提供了多种代谢功能。完全活跃的线粒体需要通过线粒体和核基因组编码的蛋白质和RNA。在人类中，至少有600个核编码蛋白被进口到线粒体中，另外13种蛋白质由线粒体基因编码。这种有限数量的线粒体编码蛋白的翻译需要线粒体核糖体，翻译因子和转移RNA。最近对进化多种生物的研究表明，某些或全部的线粒体TRNA可以被核编码，并且必须进口到线粒体中。在锥虫中，所有线粒体TRNA都是核编码的，大多数都位于线粒体和细胞质。尽管在阐明蛋白质进口到真菌和哺乳动物线粒体的机理方面取得了显着的进步，但对线粒体RNA进口的机制知之甚少。该提案的总体目标是剖析非洲锥虫中tRNA生物合成和贩运的途径。为了实现这一目标，提出了以下特定目标。在特定的目标I中，将通过体外转录和完整细胞中tRNA运输的动力学分析来研究锥虫TRNA的生物合成途径。在特定的目标II中，将确定特定序列和/或结构基序在tRNA从细胞核导出并进口到线粒体中的作用。最后，在特定的目标III中，将确定与前体和成熟的TRNA相互作用以影响tRNA运输并最终确定线粒体进口的锥虫蛋白。由于在体外和体内系统中都开发了研究tRNA合成和线粒体进口，因此锥虫为研究tRNA运输途径提供了有吸引力的模型。此外，线粒体TRNA进口可能具有治疗潜力，因为与锥虫相比，所有哺乳动物的线粒体TRNA均由线粒体基因编码。