YEAST GENES IN RNA PROCESSING & NUCLEUS/CYTOSOL EXCHANGE

描述（由申请人提供）：真核细胞的特征是存在细胞器，生物化学专业化的区域，通过膜彼此分离。这种细胞组织需要精细的机制，以在适当的条件下有效地将正确的大分子递送到正确的位置，以及用于细胞器的生物发生、维持和遗传的机制。我们的重点是核心。使用遗传方法可用于我们的模型真核生物，酵母酿酒酵母，我们以前确定Los 1 p。Los 1 p及其同源物（Xpo-t）在tRNA核出口中起作用。然而，LOS 1/Xpo-t是所有生物体中的非必需基因，可以消除其功能，需要细胞具有Los 1 p非依赖性tRNA核输出途径。拟议工作的目标1采用候选技术和全基因组技术来揭示Los 1 p独立的tRNA核输出途径。直到最近，tRNA的运动被认为是从核合成位点到胞质功能位点的单向运动。然而，我们发现反过来也会发生。事实上，在特定的生理条件下或在特定的酵母突变体中，从细胞质输入的大量tRNA快速且可逆地驻留在细胞核中。这种“逆行tRNA核输入途径”可能是所有真核生物新发现的基因表达水平。目的2旨在了解逆行途径的机制及其与细胞代谢的协调。在目标3中，我们采用全基因组方法来了解复杂和动态的细胞核是如何组织成彼此不被膜分离的结构域的。到目前为止，我们发现了N-乙酰化和一个完整的膜蛋白的必要作用，以适当地将我们的记者的内核膜。我们试图确定其他这样的基因产物，并了解是否那些已经确定履行亚核组织的一般作用。我们预计，收集到的信息将在人类疾病，如癌症，Emery-Dreifuss肌营养不良症和Hutchison-Gilford早衰症综合征中有重要的应用，这些疾病是由不适当的细胞核/细胞质动力学和细胞核组织引起的。

DESCRIPTION (provided by applicant): The presence of organelles, areas of biochemical specialization, separated from one another other by membranes, characterize eukaryotic cells. Such cellular organization necessitates elaborate mechanisms to effectively deliver the correct macromolecules to the correct locations, under the appropriate conditions, as well as mechanisms for the biogenesis, maintenance and inheritance of the organelles. Our focus is on the nucleus. Using genetic approaches available for our model eukaryotic organism, yeast Saccharomyces cerevisiae we previously identified Los1p. Los1p and its homologues (Xpo-t) function in tRNA nuclear egress. However, LOS1/Xpo-t is an unessential gene in all organisms that it has been possible to ablate its function, requiring that cells possess Los1p-independent tRNA nuclear export pathway(s). Aim 1 of the proposed work employs both candidate and genome-wide technologies to uncover the Los1p-independent tRNA nuclear export pathway(s). Until recently tRNA movement was regarded to be unidirectional from the nuclear site of synthesis to the cytosolic site of function. However, we discovered that the reverse also occurs. In fact, large pools of tRNA imported from cytoplasm quickly and reversibly reside in the nucleus under particular physiological conditions or in particular yeast mutants. This "retrograde tRNA nuclear import pathway" is likely a newly discovered level of gene expression for all eukaryotic organisms. Aim 2 seeks to understand the mechanisms that govern the retrograde pathway and its coordination with cellular metabolism. In Aim 3 we employ genome-wide approaches to learn how the complicated and dynamic nucleus is organized into domains that are not separated from each other by membranes. To date, we discovered necessary roles for N-acetylation and an integral membrane protein to appropriately tether our reporter to the inner nuclear membrane. We seek to identify other such gene products and to learn whether those already identified fulfill general roles in subnuclear organization. We anticipate that the information gleaned will have significant application in human disorders, such as cancers, Emery-Dreifuss muscular dystrophy and Hutchison-Gilford Progeria syndrome that result from inappropriate nucleus/cytosol dynamics and nuclear organization.