Biogenesis of the Small Ribosomal Subunit in Eukaryotes

真核生物中小核糖体亚基的生物发生

基本信息

批准号：
8813598
负责人：
Arlen W JOHNSON
金额：
$ 28.96万
依托单位：
UNIVERSITY OF TEXAS AT AUSTIN
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-03-01 至 2018-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8813598
关键词：
ATP phosphohydrolase Achievement Address Animal Model Base Pairing Binding Biochemical Biogenesis Budgets Bypass Cells Cleaved cell Defect Development Disease Dissociation Elements Engineering Ensure Eukaryota Eukaryotic Cell Foundations Genes Genetic Genetic Transcription Genetic screening method Goals Health In Vitro Malignant Neoplasms Mediating Messenger RNA Methyltransferase Modeling Molecular Molecular Chaperones Molecular Genetics Monitor Mutation Pathway interactions Play Positioning Attribute Process Proteins Quality Control RNA RNA Folding RNA Helicase Reaction Research Research Personnel Ribosomal Proteins Ribosomal RNA Ribosomes Role Saccharomyces cerevisiae Signal Transduction Structure Testing Translation Process Translational Research U3 small nucleolar RNA Up-Regulation Yeasts biochemical model cofactor genetic approach helicase in vivo insight mutant particle rRNA Precursor rapid growth sensor tool

项目摘要

DESCRIPTION (provided by applicant): All cells require ribosomes for translation, the process of decoding messenger RNA and synthesizing proteins. To satisfy the translational needs of a rapidly dividing eukaryotic cell, thousands of ribosomes must be synthesized per minute in a process that consumes a large portion of the cell's energy budget. Indeed, the rapid growth of many cancers requires up-regulation of ribosome biogenesis. Thus, understanding the mechanisms regulating ribosome biogenesis will provide insight for the development of new tools for controlling cell proliferationin disease states. The delineation of fundamental cellular pathways such as ribosome biogenesis is also critical for building the intellectual foundation for translational research. Many of the fundamental steps of eukaryotic ribosome biogenesis are poorly understood. Our functional genetic approach (Johnson lab) combined with the development of in vitro biochemical models (Correll lab) places us in a particularly strong position to study a fundamental step in eukaryotic ribosome biogenesis; the transition from the pre-ribosome particle (90S) to the pre-40S particle (small subunit precursor). Our overarching model is that the methyltransferase Bud23 monitors that status of 40S assembly, triggering the RNA helicase Ecm16 to promote release of the pre-40S from 90S only after completion of transcription and critical folding of the RNA. A major achievement in our preliminary results is our ability to trap an Ecm16-intermediate particle. To begin to address this model, our studies test four specific hypotheses: (i) Ecm16 is the helicase that dissociates U3 snoRNA and its associated proteins from the pre-rRNA (ii) Bud23 activates this helicase activity; (iii) Imp4 stabilizes the duplex that is the target of Ecm16; and (iv) the ribosomal protein Rps2 chaperones formation of the central pseudoknot, a key structural feature in 18S rRNA whose formation is sterically blocked until Ecm16 disrupts the U3-pre-rRNA interactions. The pre-rRNA processing pathways and the genes to be studied in the yeast Saccharomyces cerevisiae have counterparts in higher eukaryotes. Hence, S. cerevisiae is our model organism of choice because it allows us to combine powerful molecular genetic and biochemical approaches.

描述（由申请人提供）：所有细胞都需要核糖体进行翻译、解码信使 RNA 和合成蛋白质的过程。为了满足快速分裂的真核细胞的翻译需要，每分钟必须合成数千个核糖体，这个过程消耗了细胞的大部分能量预算。事实上，许多癌症的快速生长需要核糖体生物发生的上调。因此，了解调节核糖体生物发生的机制将为开发用于控制疾病状态下细胞增殖的新工具提供见解。核糖体生物发生等基本细胞途径的描述对于构建转化研究的知识基础也至关重要。人们对真核核糖体生物发生的许多基本步骤知之甚少。我们的功能遗传方法（约翰逊实验室）与体外生化模型（科雷尔实验室）的开发相结合，使我们在研究真核生物的基本步骤方面处于特别有利的地位核糖体生物发生；从前核糖体颗粒 (90S) 到前 40S 颗粒（小亚基前体）的转变。我们的总体模型是甲基转移酶 Bud23 监控 40S 组装的状态，仅在 RNA 转录和关键折叠完成后才触发 RNA 解旋酶 Ecm16 促进前 40S 从 90S 释放。我们初步结果的一个主要成就是我们能够捕获 Ecm16 中间粒子。为了开始解决这个模型，我们的研究测试了四个具体假设：（i）Ecm16是将U3 snoRNA及其相关蛋白与前rRNA解离的解旋酶（ii）Bud23激活该解旋酶活性； (iii) Imp4 稳定 Ecm16 靶标的双链体； (iv) 核糖体蛋白 Rps2 分子伴侣形成中央假结，这是 18S rRNA 的一个关键结构特征，其形成受到空间阻断，直到 Ecm16 破坏 U3-pre-rRNA 相互作用。酿酒酵母中的前rRNA加工途径和待研究的基因在高等真核生物中具有对应物。因此，酿酒酵母是我们选择的模型生物，因为它使我们能够将强大的分子遗传学和生化方法结合起来。