Chromatin Biology of the African Trypanosome

非洲锥虫的染色质生物学

基本信息

批准号：
10633288
负责人：
Erik Debler
金额：
$ 53.22万
依托单位：
THOMAS JEFFERSON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-06-02 至 2027-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10633288
关键词：
Address Affect African African Trypanosomiasis Antigenic Variation Area Biochemical Biological Biological Assay Biological Process Biology Cell Cycle Cell Cycle Deregulation Cell Cycle Progression Cell Cycle Regulation Cells Chagas Disease Chromatin Complex Cryoelectron Microscopy DNA DNA Binding DNA biosynthesis DNA replication fork Data Defense Mechanisms Development Disease Enzymes Epigenetic Process Eukaryota Exhibits Flow Cytometry Future Gene Expression Regulation Genetic Genetic Transcription Genomic DNA Goals Histone H3 Histones Human Hybrids Immune system In Vitro Intervention Kinetoplastida Knowledge Leishmania Leishmaniasis Life Lysine Medical Methylation Methyltransferase Modeling Modification Molecular Monitor Mutagenesis Nucleic Acid Regulatory Sequences Nucleosome Core Particle Nucleosomes Organism Parasites Persons Pharmaceutical Preparations Ploidies Populations at Risk Process Protozoa RNA RNA primers Regulation Research Resistance Roentgen Rays Role Signal Pathway Structure System Testing Therapeutic Transcriptional Regulation Trees Trypanosoma Trypanosoma brucei brucei Trypanosoma cruzi Variant Work X-Ray Crystallography Yeasts chromatin protein combat drug discovery effective therapy epigenetic regulation experimental study fungus global health histone methylation in vivo inducible gene expression inhibitor inhibitor therapy insight interest mutant neglected tropical diseases new therapeutic target novel novel strategies novel therapeutics overexpression pharmacologic posttranscriptional preference reconstruction recruit spatiotemporal structural determinants

Address Affect African African Trypanosomiasis Antigenic Variation Area Biochemical Biological Biological Assay Biological Process Biology Cell Cycle Cell Cycle Deregulation Cell Cycle Progression Cell Cycle Regulation Cells Chagas Disease Chromatin Complex Cryoelectron Microscopy DNA DNA Binding DNA biosynthesis DNA replication fork Data Defense Mechanisms Development Disease Enzymes Epigenetic Process Eukaryota Exhibits Flow Cytometry Future Gene Expression Regulation Genetic Genetic Transcription Genomic DNA Goals Histone H3 Histones Human Hybrids Immune system In Vitro Intervention Kinetoplastida Knowledge Leishmania Leishmaniasis Life Lysine Medical Methylation Methyltransferase Modeling Modification Molecular Monitor Mutagenesis Nucleic Acid Regulatory Sequences Nucleosome Core Particle Nucleosomes Organism Parasites Persons Pharmaceutical Preparations Ploidies Populations at Risk Process Protozoa RNA RNA primers Regulation Research Resistance Roentgen Rays Role Signal Pathway Structure System Testing Therapeutic Transcriptional Regulation Trees Trypanosoma Trypanosoma brucei brucei Trypanosoma cruzi Variant Work X-Ray Crystallography Yeasts chromatin protein combat drug discovery effective therapy epigenetic regulation experimental study fungus global health histone methylation in vivo inducible gene expression inhibitor inhibitor therapy insight interest mutant neglected tropical diseases new therapeutic target novel novel strategies novel therapeutics overexpression pharmacologic posttranscriptional preference reconstruction recruit spatiotemporal structural determinants

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项目摘要

PROJECT SUMMARY Protozoan parasites of the group kinetoplastids are responsible for major human maladies such as fatal sleeping sickness (Trypanosoma brucei, also termed the African trypanosome), Chagas disease (T. cruzi), and leishmaniasis (Leishmania species). Due to the lack of inexpensive and safe drugs, rising resistance against current drugs, and limited drug discovery efforts, novel approaches are urgently needed to combat these neglected tropical diseases. Because kinetoplastids constitute one of the earliest-branching organisms in the eukaryotic tree of life, they exhibit numerous molecular and cellular features that are distinct from metazoa and fungi, and that can be exploited for pharmacological intervention. By combining structural, biochemical, and in vivo approaches, we seek to address fundamental questions in chromatin biology and gene regulation in the model kinetoplastid T. brucei. We are particularly interested in the structure and mechanism of the closely related DOT1A and DOT1B enzymes that are key regulators of essential functions in T. brucei and that catalyze the methylation of histone H3 lysine 76 (H3K76) in the globular nucleosome core region. While DOT1A regulates cell-cycle progression, DOT1B in antigenic variation, an essential mechanism for the parasite to evade the host’s immune system. Due to significant mechanistic differences of trypanosome DOT1A/B to human and yeast DOT1 enzymes, the molecular mechanisms of how they methylate chromatin and how they are regulated remain poorly understood. In Aim 1, we will therefore investigate the mechanism of DOT1A-nucleosome substrate recognition and its impact on cell cycle control. In Aim 2, we will decipher the regulatory mechanism of DOT1A governed by RNaseH2, an enzyme that is known to cleave RNA in RNA/DNA hybrids and that has been implicated in both DNA replication and transcriptional regulation. Our goal is to define the impact of RNaseH2 on DOT1A activity, provide a structural basis for its regulatory function, and elucidate the mechanism of how DOT1A activity is coordinated with the cell cycle. The interaction of RNaseH2 with DOT1A/B is specific to trypanosomes, suggesting a novel regulatory mechanism of DOT1 enzymes. Collectively, our studies will illuminate the long- standing question of how DOT1A is recruited to chromatin and how it is regulated in a spatiotemporal manner. Our studies will yield the first atomic structures of the fundamental unit of chromatin, the nucleosome, of the vast group of protozoa, which are medically, ecologically, evolutionarily, and scientifically important eukaryotes. Due to the novel regulatory function of RNaseH2, our results will broaden our mechanistic understanding of DOT1A and RNaseH2 enzymes. Because T. brucei DOT1-regulated processes are essential for the parasite, this research may ultimately have a large impact on global health by exploiting the unique attributes of protozoan DOT1 structure and regulation to inform novel therapies for sleeping sickness and other diseases caused by kinetoplastids that affect half a billion of people.

项目摘要动力质体的原生动物寄生虫负责致命睡眠等主要人类疾病疾病（布鲁氏锥虫，也称为非洲锥虫体），Chagas病（T. Cruzi）和利什曼病（利什曼原虫物种）。由于缺乏廉价且安全的药物，抵抗力增加目前的药物以及有限的药物发现工作，迫切需要采取新颖的方法来对抗这些方法被忽视的热带疾病。因为动力质体是最早的分支生物之一它们的真核树，它们表现出许多分子和细胞特征，这些特征与后生动物和分子特征不同真菌，可以探索药物干预。通过结合结构，生化和体内方法，我们试图解决染色质生物学和基因调节中的基本问题模型动力质体T. Brucei。我们对密切相关的结构和机制特别感兴趣 dot1a和dot1b酶是t. brucei基本功能的关键调节剂，并催化全球核核小体核心区域中组蛋白H3赖氨酸76（H3K76）的甲基化。而dot1a则调节细胞周期进展，抗原变异中的dot1b，这是寄生虫逃避宿主的基本机制免疫系统。由于锥虫dot1a/b的机械差异与人和酵母dot1的显着机械差异酶，它们的甲基化染色质以及如何调节的分子机制保持较差理解齿。因此，在AIM 1中，我们将研究DOT1A-核体底物识别的机制及其对细胞周期控制的影响。在AIM 2中，我们将破译由DOT1A的调节机制 RNAseH2，一种已知可以清除RNA/DNA杂交中RNA的酶，并且已经与这两个酶有关 DNA复制和转录调控。我们的目标是定义rnaseh2对dot1a活动的影响，为其调节功能提供结构性基础，并阐明DOT1A活性的机制与细胞周期协调。 rnaseh2与dot1a/b的相互作用是特定于锥虫的，提出了一种新型的DOT1酶调节机制。总的来说，我们的研究将阐明长期的关于如何将DOT1A募集到染色质以及如何以时空方式调节的问题。我们的研究将产生疫苗染色质（核小体）基本单元的第一个原子结构。原生动物群体在医学，生态，进化和科学重要的真核生物上都是。对于RNaseH2的新调节功能，我们的结果将扩大我们对Dot1a的机械理解和RNaseH2酶。因为t。bruceidot1调节的过程对于寄生虫至关重要，所以研究最终可能通过利用原生动物的独特属性对全球健康产生重大影响 DOT1结构和调节，以告知新颖的睡眠疗法和其他疾病影响十亿人的动力质体。