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Chromatin Biology of the African Trypanosome

非洲锥虫的染色质生物学

基本信息

批准号：
10522312
负责人：
Erik Debler
金额：
$ 58.22万
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/10522312
关键词：
Address Affect African African Trypanosomiasis Antigenic Variation Area Biochemical Biological Biological Assay Biological Process Biology Blood Cell Cycle Cell Cycle Deregulation Cell Cycle Progression Cell Cycle Regulation Cells Chagas Disease Chromatin Complex Cryoelectron Microscopy Crystallization DNA DNA Binding DNA biosynthesis DNA replication fork Data Defense Mechanisms Development Disease Enzymes Epigenetic Process Eukaryota Exhibits Flow Cytometry Future Gene Expression Regulation Genes Genetic Genomic DNA Goals Histone H3 Histones Human Hybrids Immune system In Vitro Intervention Kinetoplastida Knowledge Leishmania Leishmaniasis Life Light Lysine Medical Methyltransferase Modeling Modification Molecular Monitor Mutagenesis Nucleic Acid Regulatory Sequences Nucleosome Core Particle Nucleosomes Organism Parasites Persons Pharmaceutical Preparations Pharmacology Ploidies Process Protozoa RNA RNA primers Regulation Research Resistance Risk Roentgen Rays Role Signal Pathway Structure Structure-Activity Relationship System Testing Therapeutic Transcriptional Regulation Trees Trypanosoma Trypanosoma brucei brucei Trypanosoma cruzi Variant Work X-Ray Crystallography Yeasts base 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 preference reconstruction recruit spatiotemporal

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.

项目总结