POLY A NUCLEASE AND TRANSLATION INITIATION IN YEAST

描述(改编自申请者摘要)：信使RNA(MRNA) 真核细胞的翻译启动需要多种基因的协同作用 几条不同的小路。例如，核糖体亚基必须保留 在没有信使核糖核酸的情况下解离，而信使核糖核酸必须包装成一种形式 这将被核糖体亚基识别。的第一步 翻译启动是对40年代的5‘到3’的定向扫描 RNA上的核糖体亚基，直到它与启动子密码子结合。这个 第二步是60S核糖体亚基的连接形成 单体。这项建议的目标是了解机制和 酵母中60S核糖体亚基连接步骤的调节等 了解真核细胞中的信使核糖核酸识别。过去的工作 提示60S亚基连接步骤需要多聚(A)尾巴 MRNA.最近，多聚(A)核糖核酸酶(PAN)被认为是一种 这一要求的调解人。这里描述的实验概述了 PAN在翻译中的作用将在体外用PAN依赖的方法进行研究 翻译摘录。他们将探索潘与 核糖体，并确定PAN或其他相互作用的蛋白质中的突变 用平底锅来效果吧。他们将定义PAN磷酸化的重要性 以及与其相关的蛋白在翻译途径中的表达。最后， PAN1突变表型和基因外抑制基因的特征 和合成致命突变与PAN，将被追求以获得更多 对潘在体内的作用的洞察。这项工作的结果可能会提供 对真核生物中的基本反应有更详细的了解 细胞。本文的研究成果为今后的工作探索奠定了基础 细胞转化或感染过程中这种途径的改变。

DESCRIPTION (Adapted from Applicant's Abstract): Messenger RNA (mRNA) translation initiation in eucaryotic cells requires the concerted action of several different pathways. For instance, ribosomal subunits must be kept dissociated in the absence of mRNA, and mRNA must be packaged into a form that will be recognized by the ribosomal subunits. The first step in translation initiation is the 5' to 3' directional scanning of the 40S ribosomal subunit on the mRNA until it binds to the initiator codon. The second step is the joining of the 60S ribosomal subunit to form the monoribosome. The goal of this proposal is to understand the mechanism and regulation of the 60S ribosomal subunit joining step in yeast, and more generally to understand mRNA recognition in eucaryotic cells. Past work suggests that the 60S subunit joining step requires the poly(A) tail on mRNA. Recently the poly(A) ribonuclease (PAN) has been implicated as a mediator of this requirement. The experiments described here outline how PAN's role in translation will be studied in vitro using PAN-dependent translation extracts. They will explore PAN's association with the ribosome and determine if mutations in PAN or in other proteins interacting with PAN effect it. They will define the importance of PAN phosphorylation and of its associated kinase in the translation pathways. Finally, the characterization of pan1 mutant phenotypes, and of extragenic suppressors and synthetic lethal mutations with PAN, will be pursued to gain more insight into PAN's function in vivo. The results of this work may provide a more detailed understanding of a fundamental reaction in eucaryotic cells. The results obtained may pave the way for future work exploring alterations of this pathways during cellular transformation or infection.