Eukaryotic Ribosome Assembly

真核核糖体组装

• 批准号: 10004112
• 负责人: Arlen W JOHNSON
• 金额: $ 56.81万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-14 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10004112
• 关键词: Acute T Cell Leukemia; Cells; Complex; Defect; Ensure; Eukaryota; Eukaryotic Cell; Event; Genetic Transcription; Guanosine Triphosphate Phosphohydrolases; Human; Lead; Life; Ligands; Messenger RNA; Molecular; Molecular Machines; Pathway interactions; Peptidyltransferase; Planet Earth; Production; Proteins; Quality Control; RNA; RNA Helicase; Research Personnel; Ribosomal Biogenesis Pathway; Ribosomal Proteins; Ribosomes; Role; Shwachman-Diamond syndrome; Structure; Time; Translational Research; Translations; U3 small nucleolar RNA; genetic information; human disease; interest; particle; polypeptide; scaffold

PI: Arlen W Johnson Summary Ribosomes are responsible for the rapid and accurate production of all proteins in cells in all forms of life on earth. The ability of these molecular machines to carry out faithful translation depends on their complex structure that allows dynamic interaction with ligands. The mature ribosome in eukaryotic cells is composed of two parts, the large 60S subunit that carries out polypeptide synthesis and the small 40S subunit that decodes mRNA. The assembly of a eukaryotic ribosome involves over 200 accessory assembly factors, whose function, in many cases, is still unknown. Considering the complexity of ribosome structure and function and its critical role in decoding our genetic information, ensuring their correct assembly would seem a necessary but daunting task for cells. Lately, considerable interest has been focused on mechanisms of quality control in the ribosome biogenesis pathway. This proposal focuses on two distinct topics within ribosome assembly; (1) completion of the peptidyl transferase center of the 60S subunit and the mechanisms for assessing its functional integrity and (2) the transition from the early 90S pre-ribosomal precursor to the pre-40S precursor. This proposal is directed at understanding the quality control mechanisms that assess the functional and structural integrity of the peptidyl transferase center of the subunit, upon insertion of ribosomal protein Rpl10. This proposal builds on our recent determination of the atomic structure of a preribosome and release of two factors, Tif6 and Nmd3. The release of Nmd3 and Tif6 is dependent on the two GTPases Efl1 and Lsg1 and constitutes the primary quality control check point in during 60S maturation. In humans, defects in the quality control step lead to T-cell acute lymphoblastic leukemia and Shwachman-Diamond syndrome. Assembly of the small ribosomal subunit involves stepwise cotranscriptional assembly of the 90S particle, a large protein-RNA complex, scaffolded on U3-snoRNA. However, the presence of U3 is mutually incompatible with the final folded structure of small subunit RNA and must be removed once transcription of the RNA is complete and the 90S particle has fully assembled. The transition from the 90S to pre-40S is poorly understood. We propose that the displacement of U3 by the RNA helicase Dhr1 is a primary event that drives the transition of the 90S into the pre-40S particle. We will determine how the activity of Dhr1 is regulated to ensure the timely release of U3.

PI：阿伦·W·约翰逊 概括 核糖体负责快速准确地产生所有蛋白质 存在于地球上所有生命形式的细胞中。这些分子机器执行任务的能力 忠实的翻译取决于其允许动态交互的复杂结构 与配体。真核细胞中成熟的核糖体由两部分组成： 进行多肽合成的大 60S 亚基和进行多肽合成的小 40S 亚基 解码 mRNA。真核核糖体的组装涉及 200 多个附件 装配因子，其功能在许多情况下仍然未知。考虑到 核糖体结构和功能的复杂性及其在解码我们的遗传中的关键作用 信息，确保它们的正确组装似乎是一项必要但艰巨的任务 对于细胞。最近，人们对质量机制产生了极大的兴趣。 核糖体生物发生途径的控制。该提案侧重于两个不同的主题 在核糖体组装内； (1) 60S肽基转移酶中心的完成 子单元和评估其功能完整性的机制以及（2）过渡 从90年代早期核糖体前体到40年代前体。 该提案旨在了解质量控制机制 评估肽基转移酶中心的功能和结构完整性 亚基，插入核糖体蛋白 Rpl10 后。该提案建立在我们最近的 确定前核糖体的原子结构并释放两个因子 Tif6 和Nmd3。 Nmd3 和 Tif6 的释放依赖于两个 GTPases Efl1 和 Lsg1 构成了 60S 成熟过程中的主要质量控制检查点。在 人类，质量控制步骤的缺陷导致T细胞急性淋巴细胞白血病 和Shwachman-Diamond 综合征。 小核糖体亚基的组装涉及逐步共转录 90S 颗粒的组装，这是一种大型蛋白质-RNA 复合物，支架在 U3-snoRNA 上。 然而，U3的存在与最终的折叠结构互不相容。 小亚基 RNA，一旦 RNA 转录完成就必须去除 90S颗粒已完全组装。从 90 年代到 40 年代之前的过渡很差 明白了。我们认为 RNA 解旋酶 Dhr1 对 U3 的置换是 驱动 90 年代过渡到 40 年代之前粒子的主要事件。我们将 确定如何调节 Dhr1 的活性以确保 U3 的及时释放。