Novel nucleosome composition and modifications in protozoal parasite Toxoplasma g

原生动物寄生虫弓形虫 g 的新型核小体组成和修饰

基本信息

批准号：
7688473
负责人：
Sergio Oscar Angel
金额：
$ 11.49万
依托单位：
INSTITUTE/RESEARCH/BIOTECHNOLOGY FDN
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-08-01 至 2013-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7688473
关键词：
ADP ribosylation Acetylation Acquired Immunodeficiency Syndrome Acute Acute Disease Address Apicomplexa Argentina Biology Bioterrorism C-terminal Categories Cellular Stress Chromatin Chromatin Remodeling Factor Chromatin Structure Chronic Chronic Disease Co-Immunoprecipitations Coin Collaborations Congenital Abnormality Cyst DNA DNA Folding Development Developmental Process Disease Docking Drug Delivery Systems Eimeria Enzymes Etiology Eukaryota Event Family Gene Expression Gene Expression Profile Gene Expression Regulation Genetic Genetic Transcription Genome Grant Histone Acetylation Histone Code Histone H2B Histone H4 Histones Homologous Gene Human Immunity Immunocompromised Host In Vitro Individual Infection Joints Knowledge Laboratories Lead Learning Life Life Cycle Stages Link Maps Methods Methylation Modification N-terminal Neurologic Nucleosomes Outcome Study Parasites Pathogenesis Pathogenicity Patients Phosphorylation Physiology Plasmodium Play Post-Translational Protein Processing Process Proteins Protozoa Publications Reading Reagent Role Site Staging Structure Surveys Tail Testing Tissues Toxoplasma Toxoplasma gondii Toxoplasmosis Variant Work Writing asexual base chromatin remodeling combinatorial dimer drug development histone modification in vivo insight mouse model novel pathogen promoter public health relevance research study

项目摘要

DESCRIPTION (provided by applicant): The protozoan parasite Toxoplasma gondii is an important human and veterinary pathogen. In humans, acute disease is caused by rapidly growing 'tachyzoites' while chronic diseases is caused by latent 'bradyzoite' tissue cysts; both stages are essential for disease propagation and causation. Tachyzoites are responsible for congenital birth defects and latent bradyzoites represent a continual threat to immunocompromised (AIDS) patients. The interconversion process between tachyzoites and bradyzoites is central to the parasite's survival and pathogenicity, yet it remains poorly understood. Several lines of evidence have linked chromatin remodeling with parasite development into bradyzoite cysts, but the fundamental units of chromatin - histones - remain to be characterized in this important parasite. Our preliminary results show that T. gondii has a canonical H2A as well as two H2A variants (H2AX and H2AZ). In addition, it has a canonical H2B and H2B variant (H2Bv). The H2A and H2B class of histones and histone variants in T. gondii are unusual in sequence composition and how they interact. Thus a major gap in our knowledge is how T. gondii nucleosomes are structured and post-translationally modified in the different stages of the parasite. In specific aim 1 we will determine the configuration of H2A and H2B histones in T. gondii nucleosomes and will analyze nucleosome composition of active and silent chromatin during bradyzoite development. In specific aim 2 we will identify non-histone proteins associating with T. gondii H2As and H2Bs histones during in both tachyzoites and bradyzoites. Determination of the non-histone proteins that associate with these histone variants is essential to learn more about the function of these histones in parasite physiology, and will illuminate the key proteins regulating the reading and writing of the Toxoplasma histone code. In specific aim 3, we will construct a post-translational modification map of T. gondii H2As and H2Bs histones in the different parasite stages. Given the sequence disparity and unusual variants in the T. gondii histone classes, it is important to identify the post-translational modifications on these histones during tachyzoite and bradyzoite stages. PUBLIC HEALTH RELEVANCE Toxoplasma gondii has achieved notoriety as a cause of life-threatening opportunistic disease in immunocompromised individuals. In addition, with the growing threat of bioterrorism this parasite is now listed as a Category B pathogen in the NIH/CDC list of priority pathogens. The proposal will produce a significant impact in elucidating the genetic basis and mechanisms underlying development in Toxoplasma parasites with a great potential of identifying novel drug targets against toxoplasmic chronic infection

描述（由申请人提供）：原生动物寄生虫弓形虫是一种重要的人类和兽医病原体。在人类中，急性疾病是由快速生长的“速殖子”引起的，而慢性疾病是由潜伏的“缓殖子”组织包囊引起的。这两个阶段对于疾病传播和因果关系都是至关重要的。速殖子会导致先天性出生缺陷，而潜伏的缓殖子则对免疫功能低下（艾滋病）患者构成持续威胁。速殖子和缓殖子之间的相互转化过程对于寄生虫的生存和致病性至关重要，但人们对此仍知之甚少。一些证据表明染色质重塑与寄生虫发育成缓殖子包囊有关，但染色质的基本单位——组蛋白——在这种重要的寄生虫中仍有待表征。我们的初步结果表明弓形虫具有典型的 H2A 以及两个 H2A 变体（H2AX 和 H2AZ）。此外，它还有规范的 H2B 和 H2B 变体 (H2Bv)。弓形虫中的 H2A 和 H2B 类组蛋白和组蛋白变体在序列组成及其相互作用方式上是不寻常的。因此，我们知识中的一个主要空白是弓形虫核小体在寄生虫的不同阶段是如何构造和翻译后修饰的。在具体目标 1 中，我们将确定弓形虫核小体中 H2A 和 H2B 组蛋白的构型，并分析缓殖子发育过程中活性和沉默染色质的核小体组成。在具体目标 2 中，我们将在速殖子和缓殖子中鉴定与弓形虫 H2As 和 H2B 组蛋白相关的非组蛋白。确定与这些组蛋白变体相关的非组蛋白对于更多地了解这些组蛋白在寄生虫生理学中的功能至关重要，并将阐明调节弓形虫组蛋白代码读写的关键蛋白。在具体目标3中，我们将构建弓形虫H2As和H2Bs组蛋白在不同寄生虫阶段的翻译后修饰图谱。鉴于弓形虫组蛋白类别中的序列差异和异常变异，识别这些组蛋白在速殖子和缓殖子阶段的翻译后修饰非常重要。公共卫生相关性弓形虫作为导致免疫功能低下个体危及生命的机会性疾病的原因而臭名昭著。此外，随着生物恐怖主义威胁的日益严重，这种寄生虫现已在 NIH/CDC 优先病原体清单中被列为 B 类病原体。该提案将对阐明弓形虫寄生虫发育的遗传基础和机制产生重大影响，并具有识别针对弓形虫慢性感染的新药物靶点的巨大潜力