YEAST GENES IN RNA PROCESSING & NUCLEUS/CYTOSOL EXCHANGE

描述（由申请方提供）：真核细胞具有细胞器 允许生物化学途径组分在物理上紧密接近， 在最适合活动的环境中。然而，这种组织产生细胞 生物交通问题，以有效地提供只有适当的 大分子到特定的亚细胞目的地，并维持细胞 在整个细胞周期中。此外，必须有有效的 在一些实施例中，各个隔室之间的流体连通，使得每个隔室联接到流体通道。 细胞代谢状态和细胞周期，必须有监测 能够识别、纠正或防止错误的机制。 使用酵母作为模型系统，我们的主要重点是了解 tRNA从细胞核输出到胞质溶胶，耦合tRNA加工 和核输出到细胞代谢和细胞周期，以及 确保这些重要过程的保真度的监视系统。（一） 我们将严格检验氨酰tRNA合成酶进入细胞的假设， 在输出之前先用细胞核来验证转运RNA。(2)作为唯一已知的 tRNA的输出是不必要的，很可能tRNA离开细胞核， 不止一条路。我们将检验Ccalp提供了一个 我们将进行基因研究，以确定其他途径。 (3)我们将研究参与新陈代谢的通讯机制， 胞质溶胶与tRNA加工和核输出。我们将检验这个假设 氨基酸的可用性和前体tRNA的剪接相互传递信号。在 搜索tRNA输出突变体，我们确定了ctf 13，一个已知的 着丝粒结合蛋白我们将检验Ctfl 3 p具有双重功能的假设。 在有丝分裂和tRNA核输出中起作用， 生物合成到细胞周期进程。(4)第二个焦点是 dsRNAi的作用机制和表观遗传，可能涉及 RNA代谢和核/胞质溶胶交换。初步研究表明， dsRNAi介导的基因沉默发生在芽殖酵母中。我们会找出基因 在dsRNAi介导的沉默中起作用的产物及其表观遗传 传承

DESCRIPTION (provided by applicant): Eukaryotic cells possess organelles allowing biochemical pathways components to be in close physical proximity and in environments optimal for activity. However, such organization generates cell biological traffic problems to effectively deliver only appropriate macromolecules to particular subcellular destinations and to maintain cellular organization throughout the cell cycle. Moreover, there must be effective communication between the various compartments so that each is coupled to the cellular metabolic state and to the cell cycle and there must be surveillance mechanisms able to recognize and correct or prevent mistakes. Using yeast as a model system, our primary focus is to understand the paths of tRNA export from the nucleus to the cytosol, the coupling of tRNA processing and nuclear export to cellular metabolism and the cell cycle, and the nature of the surveillance systems that assure fidelity of these important processes. (1) We will rigorously test the hypothesis that aminoacyl tRNA synthetases enter the nucleus to proof tRNAs prior to their export. (2) As the only known exportin for tRNA is unessential, it is likely that tRNA exits the nucleus by more than a single route. We will test the hypothesis that Ccalp provides an alternative path and we will undertake genetic studies to identify other paths. (3) We will study the mechanisms involved in communication of metabolism in the cytosol with tRNA processing and nuclear export. We will test the hypothesis that amino acid availability and pre-tRNA splicing signal each other. In searches for tRNA export mutants we identified ctf13, a known centromere-binding protein. We will test the hypothesis that Ctfl3p has dual functions in mitosis and tRNA nuclear export, coupling macromolecular biosynthesis to cell cycle progression. (4) A secondary focus concerns the mechanisms of action and epigenetic inheritance of dsRNAi, likely to involve RNA metabolism and nucleus/cytosol exchange. Preliminary studies indicate that dsRNAi-mediated gene silencing occurs in budding yeast. We will identify gene products functioning in dsRNAi-mediated silencing and its epigenetic inheritance.