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（由适用提供）：真核细胞面临双重挑战，即将其所有遗传信息包装到染色质中（由组蛋白/DNA复合物组成称为核小体），同时可以选择性地访问此信息以适应关键基因组过程。细胞通过建立一组组蛋白后翻译后修饰（PTM）来解决此问题，该修饰（PTMS）调节“开放”和“封闭”染色质状态之间的动态过渡。这些修饰可能通过改变染色质纤维的生物物理特性或募集效应分子的生物物理特性来促进染色质状态过渡，而效应分子又可以解释（“读取）或更改（“写”或“擦除”）修饰 改变染色质状态。组蛋白磷酸化是非常重要的PTM类型的一个特定例子。大多数研究的组蛋白磷酸化的例子都出现在丝氨酸和苏氨酸上。最好的代表性示例之一是G-H2A.X（Ser139phos），它标记了染色质的双链断裂（DSB），对于正确修复DSB以及基因组稳定性的维持至关重要，因此对于癌症发育是关键的成分。 Allis Lab对所有可能独立起作用或作为包含多种修饰的PTM基序的一部分（即乙酰/PHOS或甲基/PHOS）的所有核心组蛋白的几种磷酸化具有重要作用。这些发现有助于阐明诸如DNA修复，有丝分裂和转录等关键细胞机制。但是，由于其不稳定的性质，还有另一种类型的组蛋白磷酸化。新型分析工具的开发使我们能够克服以前的挑战，并在研究染色质环境中研究组氨酸磷酸化方面取得了重要的进展。组蛋白H4的组氨酸是组成核心组蛋白八聚体的四个组蛋白之一，已被证明是磷酸化的，并与活性转录相关。该提案中概述的工作的主要目标之一是对涉及沉积这种修饰的调节机械的机械理解，其对重要生物学过程的影响，例如转录和复制或疾病进展。一个免费的目标是确定这种修饰对染色质纤维结构特性的影响。设计师染色质是研究染色质修饰和特性的宝贵工具，将单独使用并与无细胞的转录测定系统一起使用，以测试各种染色质状态的功能输出。总体而言，这里提出的工作具有令人兴奋的潜力，可以阐明控制染色质状态和各种生物学过程之间过渡的主要调节机制。