YEAST RDNA PROJECT

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 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. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. 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.