Dissecting the Trigger of the Chromatin Modification Cycle

剖析染色质修饰周期的触发因素

• 批准号: 2230587
• 负责人: R Keith Slotkin
• 金额: $ 100万
• 依托单位: Donald Danforth Plant Science Center
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2230587&HistoricalAwards=false
• 关键词: Dissecting; Trigger; Chromatin; Modification; Cycle

The living world functions through feed-forward and feed-back cycles, establishing self-perpetuating patterns that can persist over vast timescales. A major question that remains unanswered is how self-perpetuating biological cycles are first initiated. This project has the advantage of being able to trigger one such cycle reproducibly, generating a rare opportunity to understand how a biological cycle is originally initiated. This project uses cutting-edge techniques to understand the mechanism of the first trigger responsible for initiating a feed-forward cycle that regulates DNA newly introduced into plant cells. By placing new DNA into cells, this project will experimentally dissect the mechanism of the earliest stages initiating regulation. The results of this project will inform academics and industry on how to improve plants while avoiding the initiation of troublesome cycles of unwanted regulation. This project will also directly train the next generation of scientists, providing them with thorough mentoring to prepare them for careers in biology, data analysis and technology. In addition, this project will perform outreach to a new audience at the Jackie Joyner Kersee Center in East St. Louis. This program will benefit groups that have traditionally not seen themselves as eligible for a career in science due to lack of representative models in science, and is perfectly suited for the after school programs run by the Jackie Joyner Kersee Center. The establishment of chromatin modifications is an essential first step that leads to the long-term heritable epigenetic silencing of transposable elements and some transgenes. Once initiated, chromatin modifications such as cytosine DNA methylation, are replicated and, in plants, can be propagated at specific loci across generations for centuries. However, the mechanisms dictating how DNA methylation is first targeted to a locus is poorly understood. The preliminary data in support of this project involved building the tools to study the first round of new (de novo) chromatin modification, and these data demonstrate that the production of scaffolding, non-coding RNAs at a locus is the key, milestone event required for de novo DNA methylation. This kind of event can be best studied in plants due to the recruitment of a specific RNA Polymerase (Pol V) to generate these scaffold RNAs. The overarching goals of this project are to understand how scaffold RNA target regions are selected and how Pol V is first recruited during de novo DNA methylation. This work utilizes cutting-edge techniques to dissect, at the molecular level, an unknown mechanism responsible for establishing de novo DNA methylation and triggering the long-term biological cycle of heritable, epigenetic silencing of transposable elements and transgenes.This project is co-funded by the Genetic Mechanisms Program in the Molecular and Cellular Biosciences Division and by the Plant Genome Research Program in the Integrative Organismal Systems Division.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

生命世界通过前馈和反馈循环运作，建立可以持续很长时间的自我延续模式。一个仍然没有答案的主要问题是自我延续的生物周期是如何开始的。该项目的优势在于能够重复触发一个这样的周期，从而为了解生物周期最初是如何启动提供了难得的机会。该项目使用尖端技术来了解负责启动前馈循环的第一个触发器的机制，该循环调节新引入植物细胞的DNA。通过将新的DNA放入细胞，该项目将实验性地剖析启动调节的最早阶段的机制。该项目的结果将告知学术界和工业界如何改善工厂，同时避免启动不必要的监管的麻烦循环。该项目还将直接培训下一代科学家，为他们提供全面的指导，为他们在生物学，数据分析和技术方面的职业生涯做好准备。此外，该项目将在东圣路易斯的杰基·乔伊纳·克西中心向新的观众进行宣传。该计划将使那些传统上不认为自己有资格从事科学事业的群体受益，因为他们缺乏科学方面的代表性模型，并且非常适合Jackie Joyner Kersee中心运营的课后课程。染色质修饰的建立是导致转座因子和一些转基因的长期可遗传的表观遗传沉默的必要的第一步。一旦启动，染色质修饰，如胞嘧啶DNA甲基化，被复制，并在植物中，可以在特定的基因座上繁殖几个世纪。然而，决定DNA甲基化如何首先靶向到一个位点的机制却知之甚少。支持该项目的初步数据涉及构建研究第一轮新（从头）染色质修饰的工具，这些数据表明，在基因座上产生支架非编码RNA是从头DNA甲基化所需的关键、里程碑事件。这种事件可以在植物中进行最好的研究，这是由于特定的RNA聚合酶（Pol V）的招募来产生这些支架RNA。该项目的总体目标是了解支架RNA靶区域是如何选择的，以及Pol V在从头DNA甲基化过程中是如何首先被招募的。这项工作利用尖端技术在分子水平上剖析了一种未知的机制，这种机制负责建立从头DNA甲基化并触发遗传性、转座因子和转基因的表观遗传沉默。该项目是共同的，由分子和细胞生物科学部门的遗传机制计划以及综合有机系统中的植物基因组研究计划资助该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。