MECHANISM OF MACROMOLECULAR EXPORT FROM THE NUCLEUS

描述(改编自申请人的摘要)：出口核糖核酸和 从细胞核进入细胞质的蛋白质是一种基本的细胞 这一过程是控制真核基因表达的关键步骤。这个 管理这些交通事件的机制仍然知之甚少 但非洲爪哇卵母细胞的动力学竞争研究表明， 不同的RNA类别，包括信使核糖核酸、核糖核酸、核糖核酸和核糖核酸使用不同的 出口途径。因为大多数(如果不是全部)RNA都与蛋白质有关 在细胞核中，RNA输出事件被认为是由 细胞核中的蛋白质表明，RNA输出事件是 由含有适当核输出信号的蛋白质(NESS)介导。 小型可传输信号的识别支持了这一点。 导致其快速和活跃地从细胞核输出的蛋白质。这个 拟议研究的长期目标是对不同的RNA进行表征 和蛋白质在酿酒酵母中的输出途径并了解 在分子水平上的核出口机制。更确切地说， 提出了三个具体目标：(1)P.I.将描述 核输出因子1(Xpo1p/Crm1p)及其在mRNA中的作用 出口。将使用各种生化和遗传方法来 确定与Xpo1p相互作用的因素。GTP酶的作用开始发挥作用 调节Xpo1p与其他细胞因子的相互作用将是 考察和调节(S)Xpo10、S在基因输出中的作用的适配器(S) 将被描述为。(2)NES介导的核蛋白输出 机器将被解剖。将探索遗传方法来 确定NES-蛋白质出口机制的其他组件。这 输出通路将作为一个模型系统来理解分子 大分子如何通过核孔运输的细节 复合体进入细胞质。(3)最后，P.I.将决定是否 酵母中存在不同的RNA输出途径。固定化和固定化的原位标记技术 活细胞将被用来表征不同RNA的输出 在几个变异背景下上课。如果不同的路径是 确定后，调解和规范这些出口事件的因素将是 已确认身份。

DESCRIPTION (adapted from the applicant's abstract): Export of RNA and protein from the nucleus into the cytoplasm is a fundamental cellular process and a key step in the control of eukaryotic gene expression. The mechanisms governing these transport events are still poorly understood but kinetic competition studies in Xenopus oocytes have indicated that different RNA classes, including mRNA, snRNA, tRNA and rRNA use distinct export pathways. Since most, if not all RNAs, are associated with proteins in the nucleus it was suggested that RNA export events are mediated by proteins in the nucleus it was suggested that RNA export events are mediated by proteins containing appropriate nuclear export signals (NESs). This is supported by the identification of small transferable signals in proteins that cause their rapid and active export from the nucleus. The long-term goal of the proposed research is to characterize different RNA and protein export pathways in the yeast S. cerevisiae and to understand the nuclear export mechanisms at a molecular level. More specifically, three specific aims are proposed: (1) The P.I. will characterize the nuclear export factor export in 1 (Xpo1p/Crm1p) and its role in mRNA export. A variety of biochemical and genetic approaches will be used to identify factors which interact with Xpo1p. The role of the GTPase Ran in regulating the interaction of Xpo1p with other cellular factors will be examined and the adapter(s) that mediate(s) Xpo10,s role in mRNA export will be characterized. (2) The NES-mediated nuclear protein export machinery will be dissected. Genetic approaches will be explored to identify additional components of the NES-protein export machinery. This export pathway will be used as a model system to understand the molecular details of how macromolecules are transported through the nuclear pore complex into the cytoplasm. (3) Finally, the P.I. will determine whether distinct RNA export pathways exist in yeast. In situ labeling in fixed and live cells will be used to characterize the export of the different RNA classes in several mutant backgrounds. If distinct pathways are identified, factors that mediate and regulate these export events will be identified.