Deciphering the composite S-phase in Toxoplasma gondii

解读弓形虫复合 S 期

• 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
• 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

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 Apicomplexa寄生虫对人类疾病负担产生了重大贡献，包括〜1/3人口 永久感染弓形虫弓形虫。现有治疗受到限制，并且经常对受影响最大的毒品有毒 免疫功能低下的患者人群。我们需要对寄生虫生物学的深刻了解来发展 有效的抗寄生虫药物。我们的小组侧重于研究细胞周期机制的研究 寄生虫生存并提供大量可毒靶。细胞周期计划策划细胞分裂，并 确保遗传物质的继承。 apicomplexan细胞周期与细胞明显不同 他们的主人的周期。尽管T. gondii tachyzoite除以内部发育，类似于二元分裂 常规的真核生物，细胞周期组织和调节存在实质性差异。它包括 弓形虫内部疾病的非典型S期，这是我们研究的主要重点。需要 适当的工具来检查Apicomplexan细胞周期和非常规调节器的复杂性 显着阻碍了相关研究。填补我们对我们对基本生物学的了解 Apicomplexan寄生虫和增强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标（FUCCI）探针。 在AIM 1实验中，我们将检验以下假设，即弓形虫内生细胞周期包括A 复合S/m/c相位，可在分层周期的近一半运行。使用我们的新Toxofucci探针，我们 将确定如何组织交织的S/M/C相。在AIM 2中，我们将确定 S期调节。设计的实验将检验以下假设，即与常规的S相相反 细胞周期蛋白依赖性激酶（CDK），受控螯合CDK相关激酶TGCRK5调节DNA的释放 在速二族中复制。使用TGCRK5的条件表达模型，我们将确定功能 隔离和核TGCRK5并识别TGCRK5底物。鉴于T. gondii缺乏 常规的S-CDK底物，我们希望发现一个新颖的TGCRK5网络。该项目将推动我们的 了解寄生虫生存的基本过程，并具有很高的潜力来发现未来的效率 药物靶标。