Understanding the Role of Histone Demethylases and Heterochromatin in Cell Cycle

了解组蛋白去甲基酶和异染色质在细胞周期中的作用

• 批准号: 8598908
• 负责人: Johnathan R. Whetstine
• 金额: $ 33.06万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8598908
• 关键词: Accounting; Address; Affect; Applications Grants; Binding; Binding Proteins; Biochemical; Biological Assay; Biological Process; Bromodeoxyuridine; Cell Cycle; Cell Cycle Progression; Cell Nucleus; Cells; ChIP-seq; Chromatin; Chromatin Structure; Clinical; Complex; Coupling; Cullin Proteins; DNA; DNA Replication Timing; DNA biosynthesis; Data; Defect; Development; Diagnostic; Disease; Ensure; Environment; Enzymes; Euchromatin; Event; Family member; Fiber; G1 Phase; Genetic Transcription; Genome; Genome Stability; Genomic Instability; Genomics; Goals; Grant; Heterochromatin; Histones; Human; Human Cell Line; Link; Lysine; Maintenance; Malignant Neoplasms; Mass Spectrum Analysis; Mediating; Methylation; Molecular; Outcome; Phenotype; Play; Post-Translational Protein Processing; Proteins; Proteomics; Regulation; Role; S Phase; Site; Structure; Therapeutic; Therapeutic Intervention; Time; Ubiquitin; Ubiquitination; abstracting; age related; base; cancer risk; cancer therapy; chromosome replication; in vivo; insight; novel; novel therapeutics; origin recognition complex; overexpression; public health relevance; tool; tumor; tumorigenesis; ubiquitin ligase

DESCRIPTION (provided by applicant): Abstract. Genomic instability is a major contributing factor to the development and onset of age-related diseases such as cancer. Aberrant regulation of the spatial-temporal timing of DNA replication is a critical factor involved in genomic instability and increased cancer risk. Chromatin structure plays a fundamental role in coordinating the timing of DNA replication during G1 and S phases of cell cycle. Chromatin is a highly ordered structure that contains DNA, histones, and other chromosomal proteins. Posttranslational modifications of histones influence the outcomes of numerous biological processes including transcription, replication, and chromosome maintenance. Histone 3 lysine 9 tri-methylation (H3K9me3) is considered a hallmark of heterochromatin, a repressive structure found at repetitive and telomeric regions in the genome. Alterations in H3K9me3 and heterochromatin levels result in aberrant replication timing and the onset of genomic instability and cancer. Understanding how the dynamics of methylation and heterochromatin formation and maintenance are regulated throughout cell cycle is critical for uncovering both basic principals governing replication timing, but most importantly, identifying regulatory factors that could contribute to replication timing defects and genomic instability observed in cancer. We have recently identified the JMJD2A H3K9/36 tri-demethylase as a regulator of chromatin accessibility, heterochromatin (HP13), DNA replication timing and S phase progression. We also demonstrated that JMJD2A levels and localization are regulated over cell cycle by ubiquitination, which directly impacts the role of JMJD2A in S phase progression. These data are exciting since regulating ubiquitination has emerged as a therapeutic strategy in cancer treatment. We hypothesize that HP13 and the ubiquitination of JMJD2A regulate the targeting of specific genomic regions so that orderly cell cycle progression occurs. This grant proposal will determine the impact ubiquitination has on JMJD2A cell cycle function (Aim 1) and determine how JMJD2A alters chromatin structure so that DNA replication timing is properly spatially and temporally regulated (Aim 2). In aim 1, we will use proteomic and biochemical approaches to determine the sites/regions that are modified within JMJD2A, the enzymes involved in adding and removing the ubiquitin, and their impact on JMD2A- dependent S phase progression. In aim 2, we will use genomics to determine the regions regulated by both JMJD2A and heterochromatin throughout cell cycle as well as determine the impact JMJD2A has on replication timing (i.e., initiation and/or elongation). These studies will significantly impact our basic understanding of S phase progression and clinical understanding of JMJD2A overexpressing tumors.

描述(由申请人提供)： 抽象的。基因组不稳定是癌症等与年龄相关的疾病发生和发展的主要因素。DNA复制的时空时间的异常调节是基因组不稳定和癌症风险增加的关键因素。染色质结构在细胞周期的G1期和S期的复制时间上起着基础性的作用。染色质是一种高度有序的结构，含有DNA、组蛋白和其他染色体蛋白质。组蛋白的翻译后修饰影响许多生物学过程的结果，包括转录、复制和染色体维持。组蛋白3赖氨酸9三甲基化(H3K9me3)被认为是异染色质的标志，异染色质是一种存在于基因组重复和端粒区域的抑制性结构。H3K9me3和异染色质水平的变化会导致复制时机的异常，并导致基因组不稳定和癌症的发生。了解甲基化和异染色质形成和维持的动态在整个细胞周期中是如何调控的，对于揭示控制复制时机的基本原理至关重要，但最重要的是，识别可能导致复制时机缺陷和在癌症中观察到的基因组不稳定性的调控因素。我们最近发现JMJD2AH3K9/36三甲基酶是染色质可及性、异染色质(HP13)、DNA复制时序和S阶段进展的调节因子。我们还证明了JMJD2A的水平和定位是通过泛素化来调节细胞周期的，这直接影响了JMJD2A在S期进展中的作用。这些数据令人兴奋，因为调节泛素化已成为癌症治疗的一种治疗策略。我们假设HP13和JMJD2A的泛素化调节特定基因组区域的靶向，从而发生有序的细胞周期进展。这项赠款提案将确定泛素化对JMJD2A细胞周期功能的影响(目标1)，并确定JMJD2A如何改变染色质结构，使DNA复制时间在空间和时间上得到适当调节(目标2)。在目标1中，我们将使用蛋白质组学和生化方法来确定JMJD2A中的修饰位点/区域，参与添加和移除泛素的酶，以及它们对依赖JMD2A的S阶段进展的影响。在目标2中，我们将使用基因组学来确定在细胞周期中受JMJD2A和异染色质调控的区域，以及JMJD2A对复制时间(即启动和/或延伸)的影响。这些研究将对我们对S分期的基本认识和对JMJD2A过表达肿瘤的临床认识产生重大影响。