Mechanism of tRNA Import Into Trypanosome Mitochondria

tRNA 导入锥虫线粒体的机制

• 批准号: 7023071
• 负责人: STEPHEN L HAJDUK
• 金额: $ 9.92万
• 依托单位: MARINE BIOLOGICAL LABORATORY
• 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 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7023071
• 关键词: RNA interference; Trypanosoma; genetic transcription; intracellular transport; mitochondria; mitochondrial membrane; nucleic acid chemical synthesis; nucleic acid quantitation /detection; nucleic acid structure; polymerase chain reaction; protein localization; protozoal genetics; tissue /cell culture; transfer RNA

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）：线粒体是大多数真核细胞中发现的重要细胞器，并提供多种代谢功能。完全活跃的线粒体需要由线粒体和核基因组编码的蛋白质和 RNA。在人类中，至少 600 种核编码蛋白被输入线粒体，另外 13 种蛋白由线粒体基因编码。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。最近对进化多样化生物体的研究表明，部分或全部线粒体 tRNA 可以进行核编码，并且必须导入线粒体中。在锥虫中，所有线粒体 tRNA 均由核编码，并且大多数定位于线粒体和细胞质。虽然在阐明蛋白质输入真菌和哺乳动物线粒体的机制方面取得了显着进展，但人们对线粒体 RNA 输入的机制知之甚少。该提案的总体目标是剖析非洲锥虫的 tRNA 生物合成和贩运途径。为了实现这一目标，提出以下具体目标。在特定目标 I 中，将通过完整细胞中 tRNA 运输的体外转录和动力学分析来研究锥虫 tRNA 的生物合成途径。在特定目标 II 中，将确定特定序列和/或结构基序在 tRNA 从细胞核输出和输入线粒体中的作用。最后，在特定目标 III 中，将鉴定与前体和成熟 tRNA 相互作用以影响 tRNA 运输和最终线粒体输入的锥虫蛋白。锥虫为研究 tRNA 运输途径提供了一个有吸引力的模型，因为最近开发了体外和体内系统来研究 tRNA 合成和线粒体输入。此外，线粒体 tRNA 输入可能具有治疗潜力，因为与锥虫不同，所有哺乳动物线粒体 tRNA 均由线粒体基因编码。