Control of RNA polymerase I transcription initiation and elongation

核糖体生物合成与细胞生长和增殖的速率密切相关。 由RNA聚合酶I（Pol I）介导的核糖体DNA的转录是第一个， 核糖体生物合成的限制步骤。基于其在细胞生物学中的关键作用及其最近的研究进展， 作为治疗靶点，本项目的总体目标是确定 控制Pol I活性并协调核糖体生物合成的早期步骤。 真核生物的RNA聚合酶具有特殊的作用，三种最大的核糖体RNA是 由Pol I独特合成。人们对开发Pol I作为治疗药物的兴趣越来越大。 癌症的目标，但要实现这一目标，我们必须了解酶是如何工作的， 如何监管。这个项目将部署一系列的生化策略来定义 Pol I的酶性质，并将这些性质与Pol II和III进行比较。 核糖体DNA基因座密集地填充有Pol I转录延伸复合物，并且 这些酶的转录动力学直接影响新生的 rRNA。转录延伸效率受反式作用转录延伸的影响 因子、DNA模板序列和细胞的代谢状态。来定义这些复杂的 生物化学过程是精心策划的，这个项目将使用遗传，基因组， 生物化学和生物信息学方法来鉴定控制Pol I的DNA序列 体外和体内转录延伸。 许多微调rRNA表达的转录因子已被确定。几个这样 已知转录因子影响Pol I和II，通常对Pol I和II表现出非常不同的作用。 各自的酶。了解基因表达的调控原理 需要定义转录因子发挥功能的机制。Pol I是一个 用于详细表征转录因子功能的优秀模型酶。 这个项目的总体目标，以及施耐德实验室作为一个整体，是把这个领域推向 核糖体生物合成的机械定义。对这一过程的详细了解是 对细胞生物学至关重要。此外，人们对发展 核糖体生物合成的选择性抑制剂，重点是Pol I。因此， 一个更完整的，机械的定义Pol I功能。

Ribosome biosynthesis is intimately linked to the rates of cell growth and proliferation. Transcription of the ribosomal DNA, mediated by RNA polymerase I (Pol I), is the first, rate- limiting step in ribosome biosynthesis. Based on its critical role in cell biology and its recent emergence as a therapeutic target, the overall goal of this project is to define the mechanisms that control Pol I activity and orchestrate early steps in ribosome biosynthesis. Eukaryotic RNA polymerases have specialized roles, and the three largest ribosomal RNAs are synthesized uniquely by Pol I. There is growing interest in developing Pol I as a therapeutic target for cancer, but to accomplish this goal, we must understand how the enzyme works and how it is regulated. This project will deploy a series of biochemical strategies to define enzymatic properties of Pol I and compare those properties to Pols II and III. The ribosomal DNA locus is densely packed with Pol I transcription elongation complexes, and the kinetics of transcription by these enzymes directly influence processing of the nascent rRNA. Transcription elongation efficiency is influenced by trans-acting transcription elongation factors, DNA template sequence, and metabolic status of the cell. To define how these complex biochemical processes are orchestrated this project will use a blend of genetic, genomic, biochemical and bioinformatic approaches to identify DNA sequences that control Pol I transcription elongation in vitro and in vivo. Many transcription factors that fine tune rRNA expression have been defined. Several of these transcription factors are known to affect Pols I and II, often exhibiting very different effects on the respective enzymes. To understand the principles by which gene expression is regulated there is a need to define the mechanism by which transcription factors function. Pol I is an excellent model enzyme for characterizing transcription factor function in detail. The overall goal of this project, and the Schneider lab as a whole, is to move the field toward mechanistic definition of ribosome biosynthesis. A detailed understanding of this process is fundamentally important to cell biology. Furthermore, there is growing interest in developing selective inhibitors of ribosome biosynthesis, with a focus on Pol I. Thus, there is a critical need for a more complete, mechanistic definition of Pol I function.