Deciphering the composite S-phase in Toxoplasma gondii

解读弓形虫复合 S 期

基本信息

批准号：
10744528
负责人：
Elena Suvorova
金额：
$ 22.5万
依托单位：
UNIVERSITY OF SOUTH FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-08-16 至 2025-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10744528
关键词：
Affect Alveolar Antiparasitic Agents Apicomplexa Biology Cell Cycle Cell Cycle Regulation Cell Nucleus Cell division Characteristics Chromosome Segregation Closure by clamp Cryptosporidiosis Cyclin-Dependent Kinases Cytokinesis DNA DNA biosynthesis Daughter Disease Drug Targeting Drug resistance Engineering Ensure Eukaryota Experimental Designs Focus Groups Future Genetic Materials Human Immunocompromised Host Infection Knowledge Malaria Mitosis Modeling Molecular Nuclear Organism Parasite resistance Parasites Phase Phosphotransferases Plasmodium Population Positioning Attribute Process Proteins Regulation Running S phase Severity of illness Surface Testing Therapeutic Toxoplasma Toxoplasma gondii Toxoplasmosis Ubiquitination Variant asexual burden of illness chronic infection controlled release design druggable target experimental study human disease novel nuclear division opportunistic pathogen pilot test programs segregation sensor temporal measurement tool

项目摘要

Abstract Apicomplexa parasites contribute significantly to human disease burden, including ~1/3 of human populations permanently infected with Toxoplasma gondii. Existing treatments are limited and often toxic to the most affected population of immunocompromised patients. We need a profound knowledge of parasite biology to develop efficient anti-parasitic drugs. Our group focuses on the studies of cell cycle mechanisms that are central to parasite survival and offer a wealth of druggable targets. The cell cycle program orchestrates cell division and ensures the inheritance of the genetic material. Apicomplexan cell cycles are strikingly different from the cell cycles of their hosts. Although T. gondii tachyzoite divides by endodyogeny that resembles a binary division of the conventional eukaryotes, there are substantial differences in cell cycle organization and regulation. It includes the atypical S-phase of Toxoplasma endodyogeny, which is a primary focus of our study. The need for appropriate tools to examine the intricacy of the apicomplexan cell cycle and unconventional regulators significantly impedes the related studies. To fill a major gap in our knowledge of the essential biology of apicomplexan parasites and boost the Toxoplasma cell cycle studies, we engineered a new Fluorescent Ubiquitination-based Cell Cycle Indicator (FUCCI) probe. In the Aim 1 experiments, we will test the hypothesis that Toxoplasma endodyogenic cell cycle includes a composite S/M/C phase that runs for nearly half of the division cycle. Using our new ToxoFUCCI probes, we will determine how the intertwined S/M/C phase is organized. In Aim 2, we will determine the mechanism of the S-phase regulation. Designed experiments will test the hypothesis that, contrary to conventional S-phase cyclin dependent kinase (Cdk), controlled release of the sequestrated Cdk-related kinase TgCrk5 regulates DNA replication in the tachyzoites. Using the conditional expression model of TgCrk5, we will determine the functions of the sequestered and the nuclear TgCrk5 and identify the TgCrk5 substrates. Given that T. gondii lacks conventional S-Cdk substrates, we expect to discover a novel TgCrk5 network. The project will advance our knowledge of the fundamental process of parasite survival and have a high potential to discover future efficient drug targets.

抽象的顶复门寄生虫对人类疾病负担有重大影响，包括约 1/3 的人口永久感染弓形虫。现有的治疗方法有限，而且对受影响最严重的人来说往往有毒免疫功能低下的患者群体。我们需要深厚的寄生虫生物学知识才能发展有效的抗寄生虫药物。我们小组专注于细胞周期机制的研究，这些机制是细胞周期的核心寄生虫存活并提供丰富的可药物靶点。细胞周期程序协调细胞分裂和确保遗传物质的遗传。顶复门细胞周期与细胞有显着不同它们的宿主的周期。尽管弓形虫速殖子通过内生分裂进行分裂，类似于二元分裂与常规真核生物相比，细胞周期的组织和调控存在实质性差异。它包括弓形虫内源性的非典型 S 期，这是我们研究的主要焦点。需要检查复杂的顶端复合体细胞周期和非常规调节因子的适当工具严重阻碍了相关研究。填补我们在基本生物学知识方面的重大空白 apicomplexan 寄生虫并促进弓形虫细胞周期研究，我们设计了一种新的荧光基于泛素化的细胞周期指示器 (FUCCI) 探针。在目标 1 实验中，我们将检验弓形虫内生细胞周期包括复合 S/M/C 阶段运行近一半的除法周期。使用我们新的 ToxoFUCCI 探针，我们将决定如何组织相互交织的 S/M/C 阶段。在目标 2 中，我们将确定以下机制： S相调节。设计的实验将检验以下假设：与传统的 S 相相反细胞周期蛋白依赖性激酶 (Cdk)，隔离的 Cdk 相关激酶 TgCrk5 的受控释放调节 DNA 在速殖子中复制。使用TgCrk5的条件表达式模型，我们将确定函数隔离的 TgCrk5 和核 TgCrk5 并鉴定 TgCrk5 底物。鉴于弓形虫缺乏与传统的 S-Cdk 底物相比，我们期望发现一种新颖的 TgCrk5 网络。该项目将推进我们的了解寄生虫生存的基本过程，并具有发现未来有效方法的巨大潜力药物靶点。