Role of the ubiquitin system in epigenetic regulation

泛素系统在表观遗传调控中的作用

• 批准号: RGPIN-2017-05709
• 负责人: Sheng, Yi
• 金额: $ 1.89万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=745883
• 关键词: Role; ubiquitin; system; epigenetic; regulation

Ubiquitin, a 76 amino acid small protein, is well conserved from yeast to humans. It can be covalently added onto thousands of different proteins through a process known as ubiquitination to provide diversity and dynamics to cell regulation. Histones are a group of basic nuclear proteins that bind and organize the linear DNA into the structural units called nucleosomes, which are further condensed into chromatin. Ubiquitin modification of histones is directly involved in many vital cellular functions including transcription, DNA replication, repair and gene silencing and therefore plays a critical role in the regulation of cell division, growth and differentiation. The mechanism of this histone modification and the players involved in this process are poorly characterized. The goal of our research program is to understand the mechanism and the importance of ubiquitin modification of histones in cellular regulation.In this application, we will focus on elucidation of the ubiquitin system involved in ubiquitination of histone H2A. H2A ubiquitination is involved in the maintenance of genome integrity, developmental patterning, X-chromosome inactivation and maintenance of pluripotency of stem cells. The proteins responsible for H2A ubiquitination include a cascade of enzymes, E1 (activating enzyme), E2 (conjugating enzymes) and E3 (ligases), which covalently attaching ubiquitin to specific lysine residues of H2A. Through proteomic, biochemical and cellular approaches, we propose to characterize the mechanism of H2A ubiquitination, to reveal the roles of each protein player in this process and to understand the function of H2A ubiquitination in cellular regulation. Specific aims include: (1) to reveal specific enzymes required for H2A ubiquitination in vitro and in vivo; (2) to characterize the molecular basis of H2A ubiquitination and the roles of these enzymes in gene regulation; and (3) to investigate specific enzymes that are responsible for ubiquitination of the H2A variants. By studying how these enzymes work, we will gain a better understanding of the importance of histone ubiquitination and how it is involved in the regulation of gene expression in different biological processes.

泛素是一种由76个氨基酸组成的小蛋白质，从酵母到人类都保存得很好。它可以通过一种称为泛素化的过程共价添加到数千种不同的蛋白质上，为细胞调节提供多样性和动态。组蛋白是一组基本的核蛋白，它们结合并将线性DNA组织成称为核小体的结构单元，核小体进一步凝聚成染色质。组蛋白泛素修饰直接参与转录、DNA复制、修复和基因沉默等许多重要的细胞功能，因此在细胞分裂、生长和分化的调控中起着至关重要的作用。这种组蛋白修饰的机制和参与这一过程的参与者尚不清楚。我们的研究计划的目标是了解机制和泛素修饰组蛋白在细胞调节中的重要性。在本应用中，我们将重点阐明参与组蛋白H2A泛素化的泛素系统。H2A泛素化参与维持基因组完整性、发育模式、x染色体失活和维持干细胞的多能性。负责H2A泛素化的蛋白质包括一系列酶，E1（激活酶），E2（偶联酶）和E3（连接酶），它们将泛素共价连接到H2A的特定赖氨酸残基上。我们拟通过蛋白质组学、生物化学和细胞学等方法，表征H2A泛素化的机制，揭示各蛋白在这一过程中的作用，了解H2A泛素化在细胞调控中的作用。具体目的包括：(1)揭示体外和体内H2A泛素化所需的特定酶；(2)表征H2A泛素化的分子基础以及这些酶在基因调控中的作用；(3)研究负责H2A变异体泛素化的特定酶。通过研究这些酶的工作原理，我们将更好地了解组蛋白泛素化的重要性，以及它在不同生物过程中如何参与基因表达的调节。