Epigenetic gene regulation in Arabidopsis

拟南芥表观遗传基因调控

• 批准号: 10092195
• 负责人: STEVEN E JACOBSEN
• 金额: $ 31.2万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-02-01 至 2024-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10092195
• 关键词: Arabidopsis; Binding; Biological Models; Biology; Cancer Etiology; Cells; Chemicals; Cytosine; DNA; DNA Damage; DNA Methylation; DNA Modification Methylases; DNA-Directed RNA Polymerase; Defect; Epigenetic Process; Five-Year Plans; Gene Expression; Gene Expression Regulation; Gene Silencing; Genes; Genetic; Genome; Genome Stability; Genomics; Heterochromatin; Histones; Laboratories; Laboratory Finding; Lead; Maintenance; Mass Spectrum Analysis; Methods; Methylation; Modification; Mouse-ear Cress; Nature; Pathway interactions; Pattern; Play; Post-Translational Protein Processing; Proteins; Proteomics; RNA; Repression; Research; Tissues; Untranslated RNA; derepression; gene function; histone modification; methylation pattern; mutant; prevent; protein complex; response; structural biology

Project Summary/Abstract Our laboratory focuses on the biology and mechanisms of gene silencing by DNA methylation and histone modifications, primarily using Arabidopsis thaliana as a model system. Recent efforts have focused on the mechanisms by which DNA methylation is properly patterned in the genome. The main findings are that four distinct DNA methylation pathways, driven by four different DNA methyltransferases act in self- reinforcing mechanisms to maintain cytosine methylation in three different sequence contexts, CG, CHG and CHH (where H = A, T, or C). The establishment of DNA methylation is controlled by the RNA-directed DNA methylation pathway, and studying this pathway has been a major recent focus of the lab. Most recently, the laboratory has used genetics, genomics, proteomics, and structural biology approaches to characterize the mechanisms by which two RNA polymerases, Pol IV and Pol V, act to produce non- coding RNAs that act to target RNA-directed DNA methylation to specific loci. The newest findings from the laboratory are also taking us into new directions aimed at understanding factors that act downstream of DNA methylation, to both control gene expression and to maintain genome stability. In the next five years, we plan to utilize all available approaches to understand the proteins that recognize methylated DNA and certain modified histones, and to decipher their functions in gene expression and in the maintenance of genome stability. These approaches will include mass spectrometry to directly identify proteins and protein complexes able to bind to methylated DNA and methylated histones. The laboratory will also use Arabidopsis mutant screens to identify factors that act downstream of DNA methylation and various histone marks. A post translational modification of histones called H3K27 monomethylation is critical for repression of heterochromatin. In the absence of this mark, cells undergo both inappropriate gene expression and a massive DNA damage response resulting in amplification of heterochromatic DNA. A key part of the five-year plan will be to understand the mechanisms at play, and to understand the precise nature of the relationship between gene derepression and DNA damage.

项目概要/摘要 我们的实验室专注于DNA甲基化和组蛋白基因沉默的生物学和机制 修改，主要使用拟南芥作为模型系统。最近的努力主要集中在 DNA 甲基化在基因组中正确形成模式的机制。主要发现是 四种不同的 DNA 甲基化途径，由四种不同的 DNA 甲基转移酶驱动，以自我作用的方式发挥作用。 在三种不同序列环境（CG、CHG）中维持胞嘧啶甲基化的强化机制 和 CHH（其中 H = A、T 或 C）。 DNA甲基化的建立是由RNA指导的控制的 DNA甲基化途径，对该途径的研究一直是实验室近期的主要关注点。最多 最近，该实验室利用遗传学、基因组学、蛋白质组学和结构生物学方法 描述了两种 RNA 聚合酶 Pol IV 和 Pol V 产生非 编码 RNA，将 RNA 指导的 DNA 甲基化靶向特定位点。最新发现来自 该实验室还带领我们进入新的方向，旨在了解影响下游的因素 DNA甲基化，以控制基因表达并维持基因组稳定性。在接下来的五年里 多年来，我们计划利用所有可用的方法来了解识别甲基化的蛋白质 DNA 和某些修饰的组蛋白，并破译它们在基因表达和 维持基因组稳定性。这些方法将包括质谱法来直接识别 能够结合甲基化 DNA 和甲基化组蛋白的蛋白质和蛋白质复合物。实验室 还将使用拟南芥突变体筛选来识别作用于 DNA 甲基化下游的因子， 各种组蛋白标记。称为 H3K27 单甲基化的组蛋白翻译后修饰是 对于异染色质的抑制至关重要。如果没有这个标记，细胞就会经历不适当的情况 基因表达和大量 DNA 损伤反应导致异染色质 DNA 扩增。 五年计划的一个关键部分是了解发挥作用的机制，并了解 基因去抑制和 DNA 损伤之间关系的精确性质。