YEAST RDNA PROJECT

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 为了研究染色质蛋白在基因表达和沉默中的作用，我们分析了芽期酵母核糖体DNA(RDNA)基因座上的染色质蛋白。核糖体是蛋白质合成的基本过程，它们的表达根据细胞需要多少蛋白质来调节。这又取决于他们分裂的力度有多大。在指数生长的野生型酵母中，在任何时候~150个重复的rDNA基因中，只有大约一半是活跃的，但当生长停滞时，所有的重复都变得沉默。由于重复序列相同，它们之间的行为差异一定是由相关因素的差异造成的。 这个项目有三个具体目标。首先，我们将从酵母细胞中纯化天然的rDNA染色质。其次，我们将识别结合蛋白，绘制它们在rDNA上的位置图，并使用质谱学确定它们是如何被修饰的。第三，我们将确定染色质组成的差异和rDNA之间的修饰。(转录的)和关闭的rDNA(沉默)，并描述它们的分布如何随着该基因座的逐渐激活或沉默而变化。最终的目标不仅是一个活跃和沉默的rDNA染色质图谱(包括组蛋白修饰)，而且还包括一个rDNA激活和沉默的动态模型。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. In order to study the role of chromatin proteins in gene expression and silencing, we are analyzing chromatin proteins at the ribosomal DNA (rDNA) locus in budding yeast. Ribosomes are required for the fundamental process of protein synthesis, and their expression is regulated according to how much proteins cells need. This in turn depends on how aggressively they are dividing. In wild type yeast growing exponentially, only about half the ~150 tandemly repeated rDNA genes are active at any time, but as growth plateaus all of the repeats become silenced. Since the repeats have the same sequence, differences in behavior between them must be caused by differences in associated factors. This project has three specific aims. First we will purify native rDNA chromatin from yeast cells. Second we will identify the bound proteins, map their locations along the rDNA, and determine how they are modified using mass spectrometry. Third we will determine differences in chromatin composition and modifications between rDNA that is ?on? (transcribed) and rDNA that is off (silent), and describe how their distributions change as the locus is progressively activated or silenced. The ultimate goal is not only a map of active and silenced rDNA chromatin (including histone modifications), but also a dynamic model of rDNA activation and silencing.