Role of polyhomeotic and the cohesin protein Pds5 in silencing and S phase

多同源异型和粘连蛋白 Pds5 在沉默和 S 期中的作用

• 批准号: 203-2009
• 负责人: Brock, Hugh
• 金额: $ 5.32万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2010
• 资助国家: 加拿大
• 起止时间: 2010-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=449060
• 关键词: Role; polyhomeotic; cohesin; protein; Pds5

For normal development to occur, genes must be kept off (silent) where they are supposed to be off. Silencing plays a vital role in development because it prevents genes from being turned on too early, or from being kept on. Both forms of misregulation can lead to birth defects, or to cancer. A group of about 20 proteins, called the Polycomb group proteins work together to make a the DNA of a target gene inaccessible to the proteins that turn genes on. We are studying one of these proteins, called Polyhomeotic. In previously work previously funded by NSERC, a graduate student discovered that Polyhomeotic associates with a protein (Pds5) whose known role is in holding newly replicated DNA together before cell division. Another student has shown using genetic analysis that Pds5 has an unexpected role in silencing. One of the aims of this proposal is to determine the molecular role for Pds5 in silencing. In a separate study, my students have shown using genetic analysis that Polyhomeotic is required for normal cell division, and works together with Pds5. Very surprisingly, the stage of cell division where DNA is replicated is speeded up in Polyhomeotic mutants. Another aim of this proposal is to understand why this occurs. The most likely reasons are that mutations in Polyhomeotic make it easier for the protein machinery to replicate DNA, or that mutations make more starting points for DNA replication available to the replication machinery. Pds5 is recruited by the protein machinery that makes DNA. We want to test the hypothesis that Pds5 recruits Polyhomeotic to newly replicated DNA. To do this, we have to develop a system for purifying this newly synthesized DNA in a way that does not disrupt the interaction of proteins with DNA. This is the third aim of the proposal. This research will identify the molecular basis for new role(s) for Pds5, and has the potential to provide important insight about the molecular mechanisms of silencing.

为了正常发育，基因必须在它们应该关闭的地方保持关闭（沉默）。沉默在发育过程中起着至关重要的作用，因为它可以防止基因过早开启或保持开启。这两种形式的失调都可能导致出生缺陷或癌症。 一组大约20种蛋白质，称为Polycomb组蛋白质，它们共同作用，使靶基因的DNA无法进入启动基因的蛋白质。我们正在研究其中一种蛋白质，称为Polyhomeotic。 在先前由NSERC资助的工作中，一名研究生发现Polyhomeotic与一种蛋白质（Pds 5）相关，该蛋白质的已知作用是在细胞分裂前将新复制的DNA保持在一起。另一位学生通过遗传分析表明，Pds5在沉默中具有意想不到的作用。该提议的目的之一是确定Pds 5在沉默中的分子作用。在另一项研究中，我的学生利用遗传分析表明，正常细胞分裂需要多同源异型，并且与Pds 5共同作用。非常令人惊讶的是，DNA复制的细胞分裂阶段在多同源异型突变体中加速。本建议的另一个目的是了解为什么会发生这种情况。 最可能的原因是多同源异型的突变使蛋白质机器更容易复制DNA，或者突变使复制机器可以获得更多的DNA复制起点。 Pds5被制造DNA的蛋白质机器招募。我们想验证Pds5将Polyhomeotic招募到新复制的DNA中的假设。要做到这一点，我们必须开发一种系统，以不破坏蛋白质与DNA相互作用的方式纯化这种新合成的DNA。这是建议的第三个目的。 这项研究将确定Pds 5新作用的分子基础，并有可能提供有关沉默分子机制的重要见解。