Ehrlichia modulation of polycomb group-dependent epigenetic regulation

埃里希体对多梳群依赖的表观遗传调控的调节

• 批准号: 8809777
• 负责人: JERE W MCBRIDE
• 金额: $ 22.92万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-11-01 至 2016-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8809777
• 关键词: Binding; Biological Models; Cell membrane; Cell physiology; Cells; Cellular biology; Chromatin; Complex; Development; Down-Regulation; Ehrlichia; Ehrlichia chaffeensis; Ehrlichiosis; Enzymes; Epigenetic Process; Family; Feasibility Studies; Gene Expression; Gene Expression Profile; Gene Expression Regulation; Gene Targeting; Genes; Genetic Transcription; Global Change; Goals; Gram-Negative Bacteria; Histones; Human; Immune; Immune response; Infection; Invaded; Investigation; Knowledge; Life; Ligase; Mediating; Microbe; Modification; Molecular; Mononuclear; Organism; PRC1 Protein; Pathway interactions; Pattern; Phagocytes; Polycomb; Post-Translational Protein Processing; Process; Protein Isoforms; Proteins; Recruitment Activity; Regulation; Reporting; Research; Ring Finger Domain; Role; Signal Transduction; Tandem Repeat Sequences; Tertiary Protein Structure; Therapeutic; Transcription Repressor/Corepressor; Transcriptional Regulation; Vacuole; Zoonoses; antimicrobial; base; cell type; epigenetic regulation; histone modification; human disease; insight; member; monocyte; nanomachine; novel; novel therapeutics; pathogen; pathogenic bacteria; programs; protein E; protein complex; protein degradation; protein expression; protein protein interaction; public health relevance; therapeutic target; transcription factor

 DESCRIPTION (provided by applicant): The mechanisms involved in Ehrlichia chaffeensis internalization, establishment of intracellular infection, persistence, and subversion of antimicrobial defenses are not well understood, but appear to be dependent on secreted ehrlichial effector proteins. E. chaffeensis utilizes T1S to export tandem repeat protein (TRP) effectors that escape the ehrlichial vacuole through an unknown mechanism. TRP47 and TRP120 are highly antigenic proteins that we recently determined interact with a diverse array of host proteins including, but not limited to, post translational modification ligases and epigenetic regulators. PCGF5, a component of the polycomb-repressive complex (PRC) involved in epigenetic regulation of Hox genes, strongly interacts with these TRP effectors. We have determined that polycomb group (PcG) proteins are recruited to ehrlichial vacuole and are differentially degraded. Moreover, consistent with PcG protein degradation, the PRC1- mediated H2AK119ub repressive histone mark is significantly decreased, while PRC2-mediated mark H3K27me3 is downregulated in a gene-specific manner. The objective of this proposal is to demonstrate E. chaffeensis modulates PRC controlled Hox genes through TRP-mediated degradation of PcG proteins, thereby modulating associated repressive epigenetic histone modifications. Through this investigation we will establish the mechanism by which E. chaffeensis exploits an evolutionarily conserved group of epigenetic regulators to establish a cell type-specific gene expression program that promotes intracellular survival. In the first aim, we will examine changes in PcG proteins during E. chaffeensis infection and associated epigenetic histone marks, determine molecular TRP interactions involved in PcG recruitment to the vacuole, and characterize components of PcG-protein complexes in normal and infected contexts to determine TRP induced changes. In the second aim, expression of PcG regulated Hox genes will be examined during E. chaffeensis infection by microarray, the role of specific PcG isoforms in regulating Hox gene expression during infection and survival will be examined using iRNA, and epigenetic marks will be investigated on target genes to determine the role of TRP-PcG mediated regulation. The exploitation of PcG transcriptional regulation in mononuclear phagocytes by a bacterial pathogen is novel, for which E. chaffeensis represents a model system to investigate this complex pathogen-host interaction. This investigation will define the targets and mechanisms of TRP-mediated transcriptional reprogramming strategies, and determine the roles of PcG and epigenetic marks in modulating host gene expression in order to create a cell type-specific prosurvival program. Characterization of the host cell pathways modulated by ehrlichial effectors and the molecular mechanisms involved will expand our understanding of the general principles that underlie the cell biology of infection and surviva strategies utilized by intracellular microbes. This knowledge is necessary to identify novel host targets for therapeutics based on mechanistically defined host-pathogen interactions potentially utilized by a wide range of microbes.

 描述（由适用提供）：埃里希氏菌内在化，持久性持续性和颠覆抗菌防御的涉及的机制尚不清楚，但似乎取决于分泌的ehrlichial效应蛋白质。 E. chaffeensis利用T1s导出串联重复蛋白（TRP）效应，从而通过未知机制逃脱了ehrlichial胶水液。 TRP47和TRP120是高度抗原蛋白，我们最近确定与宿主蛋白的潜水员阵列相互作用，包括但不限于翻译后修饰的连接酶和表观遗传调节剂。 PCGF5是涉及HOX基因表观遗传调节的多肉液抑制复合物（PRC）的一个成分，与这些TRP效应强烈相互作用。我们已经确定将聚酮组（PCG）蛋白募集到ehrlichial真空中，并差异降解。此外，与PCG蛋白降解一致，PRC1-介导的H2AK119UB反射组蛋白标记得到显着改善，而PRC2介导的Mark H3K27me3以基因特异性方式下调。该提案的目的是通过TRP介导的PCG蛋白降解来证明Chaffeensis E. Chaffeensis调制基因，从而调节相关的反射性表观遗传组蛋白修饰。通过这项投资，我们将建立一种机制，通过该机制，杂草息肉探索了进化保守的表观遗传调节剂，以建立促进细胞内存活的细胞类型特异性基因表达程序。在第一个目的中，我们将检查在大肠杆菌感染和相关的表观遗传组蛋白标记过程中PCG蛋白的变化，确定与PCG募集到液泡中有关的分子TRP相互作用，并表征正常和感染环境中PCG蛋白复合物的成分，以确定TRP诱导的变化。在第二个目的中，将通过微阵列进行PCG调节的HOX基因的表达，将检查特定PCG同工型在确定感染和生存过程中的HOX基因表达中的作用。细菌病原体对单核吞噬细胞中PCG转录调控的开发是新颖的，E。Chaffeensis代表了一种模型系统，用于研究这种复杂的病原体宿主相互作用。这项投资将定义TRP介导的转录重编程策略的目标和机制，并确定PCG和表观遗传标记在调节宿主基因表达中的作用，以创建特定于细胞类型的Prosurvival程序。通过ehrlichial效应和所涉及的分子机制调节的宿主细胞途径的表征将扩大我们对受细胞内微生物使用的感染和Surviva策略的基础的一般原理的理解。这些知识对于基于机械定义的宿主 - 病原体相互作用而可能被广泛利用的机械定义的宿主 - 病原体相互作用来确定治疗的新型宿主目标是必要的。