Uncovering novel players in nucleolar organization and function

项目摘要 核仁是最大的无膜细胞器之一，负责核糖体RNA（rRNA） 转录、rRNA加工和核糖体组装。核仁的大小和数量通常与 蛋白质合成速率和细胞增殖能力。精液研究表明，增加的核仁 大小和数量是许多癌症的共同特征， 神经退行性疾病，包括阿尔茨海默病和帕金森病。然而，基本 关于控制动态组装的分子参与者和机制的信息仍然缺乏， 核仁在健康和疾病中的活性。 我们鉴定了一种新的核仁蛋白ZNF 692，它是维持核仁完整性所必需的， 活动敲除ZNF 692导致异常的环状核仁形态，以及受损的 蛋白质合成我们的初步结果表明ZNF 692与多种核仁蛋白相互作用， 包括NPM1，以及rRNA加工和核糖体组装因子。我们的假设是ZNF 692 通过同时募集前rRNA、核糖体RNA和核糖体RNA， 蛋白质和核糖体生物合成因子。我们将阐明ZNF 692调控的分子机制， 核糖体产生（Aim 1）。我们将确定ZNF 692的结构域，调节核仁的完整性和活性 (Aim 2）。然后，我们将确定ZNF 692如何调节核仁组装和动力学（目的3）。我们的工作 有可能提供有关核仁活性机制和关键调节因子的基础数据， 可能成为开发改变患病细胞核仁活性的新方法的基础。

PROJECT SUMMARY The nucleolus is one of the largest membraneless cellular organelles, responsible for ribosomal RNA (rRNA) transcription, rRNA processing, and ribosome assembly. Nucleolar size and number are often correlated with protein synthesis rate and proliferative capacity of a cell. Seminal studies have shown that increased nucleolar size and number are common features of many cancers and that nucleolar defects are associated with neurodegenerative disorders, including Alzheimer’s and Parkinson’s diseases. Nevertheless, fundamental information is still lacking on the molecular players and mechanism that control the dynamic assembly and activity of the nucleolus in health and disease. We identified a novel nucleolar protein named ZNF692 that is necessary to maintain nucleolar integrity and activity. Knocking down ZNF692 resulted in abnormal ring-like nucleolar morphology, as well as compromised protein synthesis. Our preliminary results indicate that ZNF692 interacts with multiple nucleolar proteins, including NPM1, as well as rRNA processing and ribosome assembly factors. Our hypothesis is that ZNF692 assembles a hub for ribosome biogenesis in the nucleolus by simultaneously recruiting pre-rRNA, ribosomal proteins, and ribosome biogenesis factors. We will define the molecular mechanism regulated by ZNF692 in ribosome production (Aim 1). We will define the domains of ZNF692 that regulate nucleolar integrity and activity (Aim 2). We will then determine how ZNF692 may regulate nucleolar assembly and dynamics (Aim 3). Our work has the potential to provide fundamental data on the mechanisms and key regulators of nucleolar activity and could become the basis for the development of novel approaches to alter nucleolar activity in diseased cells.