Mechanism for Chromatin Accessibility through a Novel Histone Phosphorylation

通过新型组蛋白磷酸化实现染色质可及性的机制

• 批准号: 9026486
• 负责人: Tatyana Panchenko
• 金额: $ 2.41万
• 依托单位: ROCKEFELLER UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2016-08-01
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9026486
• 关键词: Binding; Binding Proteins; Biological Assay; Biological Process; Cells; Charge; Chromatin; Chromatin Fiber; Chromatin Structure; Chromosomes; Collaborations; Complex; DNA; DNA Repair; Deposition; Development; Disease Progression; Double Strand Break Repair; Drosophila genus; Eukaryotic Cell; Fluorescence Resonance Energy Transfer; Genes; Genetic Transcription; Genome Stability; Genomics; Goals; Hand; Health; Histidine; Histone H4; Histones; Human; In Vitro; Letters; Light; Maintenance; Malignant - descriptor; Malignant Neoplasms; Measures; Mitosis; Modification; N-terminal; Nature; Nucleosomes; Output; Phosphorylation; Phosphotransferases; Post-Translational Protein Processing; Prevention; Process; Property; Reading; Regulation; Research Proposals; Role; Serine; System; Tail; Testing; Threonine; Time; Training; Universities; Variant; Work; Writing; biophysical properties; career; chromatin modification; genetic information; in vivo; novel; protein complex; public health relevance; tool

 DESCRIPTION (provided by applicant): Eukaryotic cells are faced with a dual challenge of packaging all of their genetic information into chromatin (made up of histone/DNA complexes called nucleosomes) while at the same time making this information selectively accessible to accommodate key genomic processes. Cells deal with this problem by establishing a set of histone post translational modifications (PTMs) that regulate the dynamic transition between "open" and "closed" chromatin states. These modifications may promote chromatin state transitions through alterations of biophysical properties of the chromatin fiber or recruitment of effector molecules which in turn interpret ("read) or change ("write" or "erase") the modifications thus altering the chromatin state. Histone phosphorylation is one specific example of a critically important type of PTM. Most of the well-studied examples of histone phosphorylation occur on serine and threonine residues. One of the best representative examples is g-H2A.X (Ser139phos) that marks chromatin for double strand breaks (DSBs) and is vital for proper repair of DSBs as well as maintenance of genomic stability and therefore is a critical component in cancer development. The Allis lab has been instrumental in defining several phosphorylations on all of the core histones which may act independently or as part of PTM motifs containing multiple modifications (i.e. acetyl/phos or methyl/phos). These discoveries have been instrumental for elucidating such key cellular mechanisms as DNA repair, mitosis and transcription. There is, however, another class of histone phosphorylation that has eluded characterization because of its labile nature. Development of novel analysis tools allowed us to overcome previous challenges and make important headway in studying histidine phosphorylation in the chromatin context. Histidine on histone H4, one of the four histones making up the core histone octamer, has been shown to be phosphorylated and associated with active transcription. One of the main goals of the work outlined in this proposal is to gain mechanistic understanding of the regulatory machinery involved in depositing this modification, its effect on important biological processes such as transcription and replication, or disease progression. A complimentary goal is to determine the effect of this modification on the structural properties of the chromatin fiber. Designer chromatin, an invaluable tool for studying chromatin modifications and properties will be used alone and in conjunction with the cell-free transcription assay system to test the functional outputs of various chromatin states. Overall the work proposed here has exciting potential to elucidate a major regulatory mechanism that controls the transition between chromatin states as well as various biological processes.

 描述（由申请人提供）：真核细胞面临着将其所有遗传信息包装到染色质（由称为核小体的组蛋白/DNA复合物组成）中的双重挑战，同时使这些信息选择性地可用于适应关键的基因组过程。细胞通过建立一组组蛋白翻译后修饰（PTM）来处理这个问题，这些组蛋白翻译后修饰调节染色质状态在“开放”和“封闭”之间的动态转换。这些修饰可以通过改变染色质纤维的生物物理性质或募集效应分子来促进染色质状态转变，所述效应分子继而解释（“读取”）或改变（“写入”或“擦除”）所述修饰 从而改变染色质状态。组蛋白磷酸化是一种非常重要的PTM类型的一个具体例子。大多数研究充分的组蛋白磷酸化的例子发生在丝氨酸和苏氨酸残基上。最具代表性的例子之一是g-H2 A.X（Ser 139 phos），它标记染色质的双链断裂（DSB），对于DSB的正确修复以及基因组稳定性的维持至关重要，因此是癌症发展的关键组成部分。Allis实验室在定义所有核心组蛋白上的几种磷酸化方面发挥了重要作用，这些磷酸化可以独立发挥作用，也可以作为含有多种修饰的PTM基序的一部分（即乙酰基/磷酸或甲基/磷酸）。这些发现有助于阐明DNA修复、有丝分裂和转录等关键细胞机制。然而，还有另一类组蛋白磷酸化由于其不稳定的性质而无法表征。新的分析工具的开发使我们能够克服以前的挑战，并在研究染色质背景下的组氨酸磷酸化方面取得重要进展。组蛋白H4上的组氨酸是组成核心组蛋白八聚体的四种组蛋白之一，已被证明是磷酸化的并与活性转录相关。本提案中概述的工作的主要目标之一是获得对沉积这种修饰所涉及的调节机制的机械理解，其对重要生物过程如转录和复制或疾病进展的影响。一个互补的目标是确定这种修饰对染色质纤维结构特性的影响。设计者染色质，一个非常宝贵的工具，用于研究染色质的修改和属性将单独使用，并与无细胞转录测定系统结合使用，以测试各种染色质状态的功能输出。总的来说，这里提出的工作具有令人兴奋的潜力，阐明了一个主要的调控机制，控制染色质状态之间的过渡，以及各种生物过程。