MATURATION OF THE LARGE RIBOSOMAL SUBUNIT IN YEAST

描述(来自申请表)：本提案旨在理解 酵母大核糖体亚基的生物发生及其在酵母中的募集 翻译。核糖体对所有细胞的生存都是必不可少的。在……里面 活跃生长的细胞，核糖体的生物发生在很大程度上 细胞的能量消耗以及核糖体的生物发生必须是 与细胞的新陈代谢需求相协调。细胞快速增殖 需要上调核糖体的生物发生。从而控制核糖体 生物发生对正常发育很重要。 我们鉴定了Nmd3p，这是酵母中一种保守的、必不可少的蛋白质，即 在大亚基生物发生的后期阶段所必需的。我们有 最近发现，Nmd3p与60S亚基形成稳定的复合体，并且 这个复合体既有新生的亚基，也有成熟的亚基。因此，Nmd3p是一个 结合核糖体生物发生和翻译的蛋白质。在这份提案中，我们 将使用遗传和生化技术来确定Nmd3p在 亚单位生物发生及其在翻译中的作用。这项工作将涉及 新生和成熟的60S核糖体亚基和Will的纯化 首次提供了这些络合物的物理表征。 除了分析Nmd3p之外，我们还将测试两个型号的功能 由Ski2p、Ski3p和Ski8p组成的蛋白质复合体。滑雪中的突变 基因导致Poly(A)-mRNA的翻译增加和减少 3‘-信使核糖核酸降解。解释这些结果的两个模型是 复合体是正常60S功能所必需的，或者此复合体在 3‘-mRNA降解途径。将进行实验，以区分 在这两个模型之间。

DESCRIPTION (from the application): This proposal is directed at understanding biogenesis of the large ribosomal subunit in yeast and its recruitment into translation. The ribosome is essential for the viability of all cells. In actively growing cells, ribosome biogenesis accounts for a large part of the energy expenditure of the cell and consequently ribosome biogenesis must be coordinated with the metabolic needs of a cell. Rapid cellular proliferation requires upregulation of ribosome biogenesis. Thus control of ribosome biogenesis is important for normal development. We identified Nmd3p, a conserved and essential protein in yeast, that is required for a late step in biogenesis of the large (60S) subunit. We have recently shown that Nmd3p forms a stable complex with 60S subunits and that this complex contains both nascent and mature subunits. Thus, Nmd3p is a protein that couples ribosome biogenesis and translation. In this proposal we will use genetic and biochemical techniques to determine the role of Nmd3p in subunit biogenesis as well as its role in translation. This work will involve the purification of nascent and mature free 60S ribosomal subunits and will provide the first physical characterization of these complexes. In addition to the analysis of Nmd3p we will test two models for the function of the protein complex composed of Ski2p, Ski3p and Ski8p. Mutations in the SKI genes result in elevated translation of poly(A)- mRNA and reduced 3'-degradation of mRNA. Two models accounting for these results are that this complex is required for normal 60S function or that this complex acts in a 3'-mRNA degradation pathway. Experiments will be carried out to distinguish between these two models.