Histone demethylases and regulation of chromatin and transcription in eukaryotes

真核生物中组蛋白去甲基化酶以及染色质和转录的调节

• 批准号: 8460446
• 负责人: Yang Shi
• 金额: $ 28.19万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-13 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8460446
• 关键词: Acetylation; Address; Affect; Biochemical; Biological; Biological Assay; Cell Cycle Arrest; Cell Death; Cells; Chromatin; Complex; Coupled; DNA Damage; DNA Double Strand Break; DNA Repair; DNA biosynthesis; Defect; Development; Double Strand Break Repair; Enzymes; Epigenetic Process; Eukaryota; Event; Funding; Genetic Transcription; Genome Stability; Health; Histone H2A; Histones; In Vitro; Investigation; Lead; Light; Malignant Neoplasms; Mass Spectrum Analysis; Mediating; Methylation; Methyltransferase; Modeling; Modification; Molecular; Mono-S; N-terminal; Nuclear; Nucleosomes; Oncogenic; Pathway interactions; Phenocopy; Phosphorylation; Play; Process; Proteins; RNA Interference; Recruitment Activity; Regulation; Role; Signal Transduction; Site; Tail; Testing; Transcriptional Regulation; Work; base; chromatin immunoprecipitation; cofactor; demethylation; gene repair; histone modification; improved; insight; novel; protein protein interaction; recombinational repair; repaired; research study; response

DESCRIPTION (provided by applicant): The N-terminal tails of histone proteins are heavily decorated by a plethora of covalent modifications including methylation, acetylation, phosphorylation, sumoylation and ubiquitylation. These modifications work together to generate appropriate chromatin templates for a host of important nuclear events, including transcription, DNA replication, recombination and repair. A defect in the DNA damage signaling and repair machinery can lead to the development of cancer, and therefore understanding the mechanisms that control this pathway has important health implications. In recent years, although significant progress has been made in our understanding of histone modifications in transcriptional regulation, much less is known about how these modifications impact the DNA damage response (DDR) and the precise molecular mechanisms by which histone- modifying enzymes regulate the DDR pathway. In the past funding period, we discovered that the histone demethylase LSD1, which thus far is thought to function only as a transcriptional regulator, also plays an evolutionarily conserved role in the DDR. Loss of LSD1 does not affect the expression of repair genes; furthermore, chromatin immunoprecipitation places LSD1 at DNA damage sites, suggesting a direct involvement of LSD1 in this process. Importantly, loss of LSD1 results in impaired histone H2A/H2A.X ubiquitylation, with subsequent loss of 53BP1 recruitment, a molecule important for DNA damage repair. In this application, we propose to test our hypothesis that a novel crosstalk exists between histone H3K4 demethylation and H2A/H2A.X ubiquitylation important for the DDR by identifying molecular mechanisms by which LSD1 regulates histone H2A/H2A.X ubiquitylation. Given that LSD1 mediates demethylation of mono- and di-methylated histone H3K4, we will also investigate whether H3K4 methylation dynamics is generally important for the DDR by determining whether demethylases for the tri-methylated H3K4 as well as a host of H3K4 methyltransferases also play a role in the DDR. Lastly we will begin to address the question of whether there is a specific constellation of histone modifications at DNA damage sites that induce a distinct chromatin domain for DNA repair, by delineating the histone modification landscape and the responsible enzymes at DNA damage sites. We anticipate that new paradigms to emerge from the proposed studies, significantly impacting our understanding of epigenetic regulation in the DDR.

描述(由申请人提供)： 组蛋白的N端被大量的共价修饰修饰，包括甲基化、乙酰化、磷酸化、总甲基化和泛素化。这些修饰共同作用，为一系列重要的核事件生成适当的染色质模板，包括转录、DNA复制、重组和修复。DNA损伤信号和修复机制的缺陷可能导致癌症的发展，因此了解控制这一途径的机制具有重要的健康意义。近年来，尽管我们对组蛋白修饰在转录调控方面的理解已经取得了重大进展，但对于这些修饰如何影响DNA损伤反应(DDR)以及组蛋白修饰酶调控DDR途径的确切分子机制还知之甚少。在过去的资助期间，我们发现组蛋白去甲基酶LSD1，到目前为止被认为只作为转录调节因子，在DDR中也扮演着进化上保守的角色。LSD1的缺失不影响修复基因的表达；此外，染色质免疫沉淀将LSD1放置在DNA损伤位置，表明LSD1直接参与了这一过程。重要的是，LSD1的丢失会导致组蛋白H2A/H2A.X泛素化受损，从而导致53BP1募集的丢失，53BP1是DNA损伤修复的重要分子。在这个应用中，我们建议通过识别LSD1调节组蛋白H2 A/H 2A.X泛素化的分子机制来验证我们的假设，即组蛋白H3K4去甲基化和H 2A/H 2A.X泛素化之间存在着对DDR重要的新的串扰。鉴于LSD1介导组蛋白H3K4单甲基化和双甲基化的去甲基化，我们还将通过确定三甲基化的H3K4去甲基酶以及一系列H3K4甲基转移酶是否也在DDR中发挥作用，来研究H3K4甲基化动力学是否对DDR普遍重要。最后，我们将通过描绘组蛋白修饰的图景和DNA损伤部位的负责酶，开始解决DNA损伤部位是否存在特定的组蛋白修饰星座，从而诱导DNA修复的独特染色质结构域。我们预计，拟议的研究将出现新的范式，显著影响我们对DDR中表观遗传调控的理解。