Epigenetic control of virulence in a fungal meningitis pathogen

真菌性脑膜炎病原体毒力的表观遗传控制

• 批准号: 9094454
• 负责人: Hiten D Madhani
• 金额: $ 38.62万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9094454
• 关键词: Accounting; Animals; Biological; Chromatin; Chromosomes; Complex; Cryptococcus; Cryptococcus neoformans; DNA; DNA Sequence; Deacetylase; Defect; Deposition; Development; Epigenetic Process; Event; Fission Yeast; Fungal Meningitis; Gene Expression; Gene Expression Regulation; Gene Silencing; Genes; Genetic; Genome; Genotype; Goals; Health; Heterochromatin; Histone Deacetylase; Histone H3; Homologous Gene; Human; Investigation; Licensing; Lysine; Malignant Neoplasms; Mediating; Mediator of activation protein; Memory; Methylation; Methyltransferase; Modeling; Molecular; PRC1 Protein; Phenotype; Plants; Play; Polycomb; Property; Proteins; Reaction; Regulation; Reporting; Repression; Role; Signal Transduction; Site; System; Testing; Variant; Virulence; Work; base; biochemical tools; disorder control; epigenetic memory; fungus; insight; microbial; pathogen; research study

 DESCRIPTION (provided by applicant): We have discovered a Polycomb repressive complex, PRC2, in the fungal meningitis pathogen Cryptococcus neoformans, that silences chromatin domains via methylation of histone H3 on lysine 27 (H3K27me). This is the first Polycomb system to be identified in a human pathogen. We propose to define the core properties and components of this system and to investigate the role of H3K27me regulation in adaptation to the host. The Polycomb silencing systems of animals and plants are critical epigenetic regulators of development that, remarkably, mediate heritable memory of prior developmental and environmental events. Polycomb systems are composed of the PRC2 complex, which catalyzes H3K27me, and the PRC1 complex, which monoubiquitylates H2A and mediates chromatin compaction. Such chromatin is also designated facultative heterochromatin because it can be dynamically regulated. The genomes of a handful of other fungi have also been reported to encode predicted PRC2 components, raising the possibility that the system functions as a general epigenetic regulator in this kingdom. We purified the five-subunit PRC2-like complex of C. neoformans and showed that it mediates subtelomeric H3K27 trimethylation (H3K27me3) and gene silencing near chromosome ends. Our studies also revealed that a chromodomain subunit of the PRC2 complex directly recognizes the H3K27me3 product of the methyltransferase, thereby effectively tethering the PRC2-like complex to the sites of previous action. Our finding that the disruption of this tethering activity results in ectopic H3K27me3 deposition at H3K9me-marked sites of constitutive heterochromatin was unexpected and demonstrates the utility of the system for obtaining new insights. The powerful genetic and biochemical tools available in C. neoformans provide unique opportunities both to elucidate the fundamental properties of a Polycomb system and to investigate the biological role of H3K27me regulation in the adaptation of a pathogen to its mammalian host. To accomplish these goals we will 1) elucidate the core properties of PRC2-mediated gene regulation, 2) define the molecular components of the C. neoformans Polycomb system, and 3) investigate the role of Polycomb in the modulation of virulence. These experiments will elucidate inputs and epigenetic properties of this mechanism, the first Polycomb system to be uncovered in a human pathogen. Furthermore, the proposed work will identify new mediators of a fungal Polycomb system, illuminate its relationship with its animal and plant counterparts, and enable mechanistic investigations. Finally, these studies will elucidate the role of H3K27me regulation in pathogen adaptation to the host.

 描述（由适用提供）：我们在真菌脑膜炎病原体中发现了Polycomb抑制性复合物PRC2，Neoformans是在赖氨酸27（H3K27ME）上通过组蛋白H3的甲基化甲基化的染色质域。这是第一个在人类病原体中鉴定的多肉液系统。我们建议定义该系统的核心特性和组件，并研究H3K27ME调节在适应宿主中的作用。动物和植物的Polycomb沉默系统是重要的表观遗传调节因子，它显着地是对先前发育和环境事件的媒体可遗传记忆。 PolyComb系统由催化H3K27ME的PRC2复合物和PRC1复合物，该复合物将H2A单调并介导染色质压实。这种染色质也被指定为兼性异染色质，因为它可以动态调节。还报道了一些其他真菌的基因组编码预测的PRC2成分，从而提高了该系统在该王国中充当一般表观遗传调节剂的可能性。我们纯化了Neoformans的五亚基PRC2样复合物，并表明它介导了亚电体H3K27三甲基化（H3K27me3）和染色体末端附近的基因沉默。我们的研究还表明，PRC2复合物的染色体亚基直接识别甲基转移酶的H3K27me3产物，从而有效地将类似Prc2的复合物绑在了先前作用的位置上。我们的发现，这种束缚活性的破坏导致构成异染色质的H3K9me标记的位点的Ecopic H3K27me3沉积是出乎意料的，并证明了系统获得新见解的实用性。 C. Neoformans可用的强大遗传和生化工具提供了独特的机会，既可以阐明Polycomb系统的基本特性，又要研究H3K27ME调节在适应其哺乳动物宿主中的H3K27ME调节的生物学作用。为了实现这些目标，我们将1）阐明PRC2介导的基因调节的核心特性，2）定义Neoformans Polycomb系统的分子成分，以及3）研究PolyComb在病毒调节中的作用。这些实验将阐明该机制的输入和表观遗传特性，这是第一个在人类病原体中发现的多肉液系统。此外，拟议的工作将确定真菌Polycomb系统的新调解人，阐明其与动物和植物对应物的关系，并实现机械投资。最后，这些研究将阐明H3K27ME调节在病原体适应宿主中的作用。