tRNA Processing

tRNA处理

• 批准号: 8573155
• 负责人: Eric M. Phizicky
• 金额: $ 4.8万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-05-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8573155
• 关键词: 8-methylguanosine; Address; Animal Model; Anticodon; Biological; Biological Assay; Biology; Cell Line; Cells; Complex; Crude Extracts; Defect; Disease; Distant; Dominant-Negative Mutation; Dose; Drosophila genus; Eukaryota; Fission Yeast; Goals; Growth; Health; Homologous Gene; Human; Knock-out; Lesion; Leucine-Specific tRNA; Link; Mass Spectrum Analysis; Mental Retardation; Messenger RNA; Methods; Methylation; Methyltransferase; Modeling; Modification; Mutation; Names; Nature; Organism; Orthologous Gene; Pathway interactions; Phenotype; Phenylalanine-Specific tRNA; Point Mutation; Proteins; Quality Control; RNA Decay; RNA Processing; Reporting; Ribosomes; Role; Saccharomyces cerevisiae; Series; Specificity; Structure; Study models; Transfer RNA; Translations; Work; X-Linked Mental Retardation; Yeasts; base; big gastrin; cell growth; crosslink; fly; follow-up; in vivo; mutant; overexpression; protein complex; public health relevance; research study; stem

DESCRIPTION (provided by applicant): Modifications are found in all tRNA species from all organisms. A typical yeast tRNA has two to three modifications in and around the anticodon loop, where decoding takes place, and another ten modifications in the main body of the tRNA, remote from the anticodon loop. These modifications have crucial roles, many of which have emerged in the last few years, but many of which are still poorly understood. Work in this lab focuses on two major aspects of the biology of tRNA and its modifications in the yeast Saccharomyces cerevisiae. One project addresses the biology and mechanisms of a rapid tRNA decay quality control pathway that acts widely on specific mature tRNAs that lack one or more of several different modifications, or that have mutations that perturb structure in the acceptor and/or T-stem. A second project addresses specific modifications in the anticodon loop that have important functions in translation, with a major effort to understand the biology and specificity of Trm7, which is required for 2'-O-methylation of residues C32 and N34 to make Cm32 and Nm34 in tRNAPhe, tRNATrp and tRNALeu(UAA). S. cerevisiae trm7-¿ mutants have a severe growth defect, which this lab recently showed is due to lack of sufficient functional tRNAPhe. Furthermore, this lab also provided evidence for a complex circuitry of anticodon loop modification of tRNAPhe, in which Trm7 interacts with YMR259c (now named Trm732) for formation of Cm32, and with Rtt10 (now named Trm734) for formation of Gm34, which in turn drives modification of 1-methylguanosine to yW (wyebutosine). This lab has speculated that the Trm7:Trm732 and Trm7:Trm734 complexes and the unusual circuitry of anticodon loop modification of tRNAPhe are widely conserved and important in eukaryotes. In support of this speculation, the putative human TRM7 homolog FTSJ1 is strongly associated with non-syndromic X-linked mental retardation, and the corresponding TRM7 homolog from Schizosaccharomyces pombe is reported to be essential. Furthermore, almost all characterized eukaryotic tRNAPhe species have Cm32 and Gm34, orthologs of Trm7, Trm732, and Trm734 are found in almost all eukaryotes, and the human Trm7 and Trm732 orthologs function in S. cerevisiae. Based on these observations, the main goal of this proposal is to determine if the complex circuitry for anticodon loop modification of tRNAPhe is conserved and important in eukaryotes. This goal will be addressed by (A.) Defining requirements in S. cerevisiae for interaction and activity of Trm732 and Trm734 with Trm7; and (B.) Determining if the complex circuitry and importance of Trm7 modification of the anticodon loop is conserved in other eukaryotes. By examining the parameters that define the Trm7 interactions in S. cerevisiae, and by defining the Trm7 complexes and their target tRNAs in S. pombe, Drosophila, and humans, we will acquire sophisticated understanding of this critically important set of tRNAPhe modifications in the anticodon loop.

描述（由申请人提供）：在所有生物体的所有 tRNA 物种中都发现了修饰，典型的酵母 tRNA 在反密码子环内部和周围（解码发生的地方）有两到三个修饰，并且在 tRNA 主体中有另外十个修饰。远离反密码子环的这些修饰具有至关重要的作用，其中许多是在过去几年中出现的，但其中许多仍然知之甚少，该实验室的工作重点是生物学的两个主要方面。酿酒酵母中的 tRNA 及其修饰研究了一种快速 tRNA 衰减质量控制途径的生物学和机制，该途径广泛作用于缺乏一种或多种不同修饰或具有扰乱结构的突变的特定成熟 tRNA。第二个项目涉及反密码子环中在翻译中具有重要功能的特定修饰，重点是了解 Trm7 的生物学和特异性，这是 Trm7 所需的。 tRNAPhe、tRNATrp 和 tRNALeu(UAA) 中残基 C32 和 N34 的 2'-O-甲基化产生 Cm32 和 Nm34。突变体具有严重的生长缺陷，该实验室最近表明这是由于缺乏足够的功能性 tRNAPhe 此外，该实验室还提供了 tRNAPhe 反密码子环修饰的复杂电路的证据，其中 Trm7 与 YMR259c（现称为 Trm732）相互作用。形成 Cm32，并与 Rtt10（现命名为 Trm734）形成 Gm34，这反过来又驱动了1-甲基鸟苷转化为 yW（wyebutosine）。本实验室推测 Trm7:Trm732 和 Trm7:Trm734 复合物以及 tRNAPhe 的反密码子环修饰的异常电路在真核生物中广泛保守且重要。 TRM7 同源物 FTSJ1 与非综合征性 X 连锁智力低下密切相关，并且据报道，来自粟酒裂殖酵母的相应TRM7同源物是必需的。此外，几乎所有特征性真核tRNAPhe物种都具有Cm32和Gm34，几乎所有真核生物中都发现了Trm7、Trm732和Trm734的直系同源物，并且人类Trm7和Trm732直系同源物在其中发挥作用。基于这些观察，酿酒酵母的主要目标是该提案旨在确定 tRNAPhe 的反密码子环修饰的复杂电路在真核生物中是否保守且重要。该目标将通过 (A.) 定义酿酒酵母中 Trm732 和 Trm734 与 Trm7 的相互作用和活性的要求来实现。 (B.) 通过检查反密码子环的 Trm7 修饰的复杂电路和重要性是否在其他真核生物中保守。定义酿酒酵母中 Trm7 相互作用的参数，并通过定义粟酒裂殖酵母、果蝇和人类中的 Trm7 复合物及其目标 tRNA，我们将深入了解反密码子环中这组至关重要的 tRNAPhe 修饰。