Cyclin-mediated control of Toxoplasma development

细胞周期蛋白介导的弓形虫发育控制

• 批准号: 10161722
• 负责人: Elena Suvorova
• 金额: $ 37.38万
• 依托单位: UNIVERSITY OF SOUTH FLORIDA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-08 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10161722
• 关键词: Acquired Immunodeficiency Syndrome; Acute; Affect; Animal Model; Animals; Architecture; Auxins; Biochemical; Biological; Biological Assay; Biology; Cell Cycle; Cell division; Cells; Chronic; Chronic Disease; Clinical; Complex; Cyclins; Cyst; Development; Differentiation and Growth; Disease; Disease Outbreaks; Disease Progression; Drug Targeting; Ensure; Equilibrium; Eukaryota; Evaluation; Foundations; Frequencies; G1 Phase; Gene Expression; Genetic; Genetic Models; Genome; Goals; Human; Immune; Immune response; Immune system; Immunity; Immunocompromised Host; In Vitro; Individual; Infection; Kentucky; Life; Link; Measures; Mechanics; Mediating; Modeling; Monitor; Mothers; Mus; Organ Transplantation; Parasites; Parasitic infection; Patients; Pharmaceutical Preparations; Phosphotransferases; Population; Post-Translational Protein Processing; Pregnancy; Proteomics; Readiness; Regulation; Rest; Role; Site; Specialist; Testing; Time; Toxoplasma; Toxoplasma gondii; Toxoplasmosis; Universities; Woman; base; chemotherapy; differential expression; effective therapy; experience; experimental study; human pathogen; immune function; in vitro activity; in vivo; mouse model; mutant; novel; prenatal; prevent; protein expression; success; transmission process

Project Abstract Toxoplasma gondii is an important human pathogen that causes severe disease in immunocompromised individuals, such as those undergoing chemotherapy, organ transplantation, and AIDS patients. It also afflicts women who become infected for the first time during pregnancy. A healthy immune system or current drug regiment controls the replication of the tachyzoites associated with clinical toxoplasmosis. However, there are no effective therapies to eliminate the chronic stages associated with encysted bradyzoites and, importantly, to prevent the cyst reactivation. To find new avenues for combating the chronic and reactivated toxoplasmosis, we focus on the mechanisms of the tachyzoite and bradyzoite interconversions that are poorly understood. The critical difference between a tachyzoite and a bradyzoite is the rate of parasite replication and the cell cycle architecture. A tachyzoite divides fast and has a relatively short G1 period. In contrast, a bradyzoite rarely divides and spends a progressively longer time in the G1 phase. The time parasite spends in the G1 period is regulated by the RESTRICTION checkpoint (R-point) that in T. gondii lacks conventional regulators. The current application is based on the central hypothesis that the atypical TgCrk2 kinase and P-type cyclins define the novel G1 checkpoint that governs transitions between acute and chronic toxoplasmosis. In our preliminary studies, we showed a differential expression of three P-cyclins in the fast- (RH) and slow-dividing (ME49) T. gondii strains, which also differ in their ability to differentiate. We also showed that all three P-cyclins interact with G1 kinase TgCrk2 in vivo. We believe that P-cyclins differentially regulate levels of TgCrk2 activity, therefore, facilitate or block R-point passage. This dictates the parasite’s choice to either replicate as a tachyzoite or to convert into a resting bradyzoite. To prove our hypothesis, we will define the mechanism of the R-point regulation by TgCrk2 kinase and cyclins TgCycP2, and TgCycP3 in the tachyzoite and bradyzoite development in vitro (Aim 1); in the natural progression of the disease using mouse model (Aim 2); and determine function of the novel R-point components TgCables1 and TgRch1 (Aim 3). Our proposal is built on a strong foundation of advanced genetics, which is bolstered by our extensive experience in studying cyclin/Crk regulators of the T. gondii tachyzoite cell cycle. Using a panel of strains with novel auxin-dependent conditional protein expression of P-cyclins, we will test whether differences in regulation of TgCrk2/P-cyclin complexes explain the dynamics of the bradyzoite differentiation and cyst reactivation. Altogether, our experiments will break new ground in understanding the mechanics and regulation of the developmental switch that regulates the progression of the disease.

项目摘要 弓形虫Gondii是一种重要的人类病原体，在免疫功能低下会引起严重疾病 个体，例如接受化疗，器官移植和艾滋病患者的人。这也折磨了 怀孕期间第一次感染的妇女。健康的免疫系统或当前药物 团控制着与临床弓形虫病有关的速二核的复制。但是，有 没有有效的疗法来消除与百科全书有关的慢性阶段，重要的是 防止囊肿重新激活。为了找到打击慢性和重新激活弓形虫病的新途径，我们 专注于次唑岩和曲二核的机制，这些机制知之甚少。这 tachyzoite和Bradyzoite之间的临界差异是寄生虫复制的速率和细胞周期 建筑学。 tachyzoite会迅速划分，G1时期相对较短。相比之下，一个小核很少分裂 并在G1阶段花费更长的时间。寄生虫在G1期间花费的时间受调节 通过限制检查点（R-POINT），T。Gondii中缺少常规调节器。电流 应用基于中心假设，即非典型TGCRK2激酶和P型细胞周期蛋白定义了 新型的G1检查点，该检查点控制着急性和慢性弓形虫病之间的过渡。在我们的初步中 研究，我们在快速（RH）和缓慢分裂（ME49）T中显示了三个P-Cyclin的差异表达。 Gondii菌株，它们的分化能力也有所不同。我们还表明，所有三个P-环蛋白都相互作用 与G1激酶TGCRK2在体内。我们认为，P-Cyclins对TGCRK2活性的水平有所不同，因此 促进或阻止R点密码。这决定了寄生虫的选择，要么复制为tachyzoite或 转化为静止的bradyzoite。为了证明我们的假设，我们将定义R点调节的机制 由TGCRK2激酶和细胞周期蛋白TGCYCP2，以及Tachyzoite和Bradyzoite开发中的TGCYCP3 体外（目标1）；在使用小鼠模型的疾病自然发展中（AIM 2）；并确定功能 新型的R-点组件TGCABLES1和TGRCH1（AIM 3）。我们的建议建立在一个强大的基础上 高级遗传学，这是我们在研究T的细胞周期蛋白/CRK调节剂方面的丰富经验所支持的。 Gondii tachyzoite细胞周期。使用与新型生长素有关的条件蛋白表达的菌株面板 在p-cyclins中，我们将测试TGCRK2/p-Cyclin复合物调节的差异是否解释了动力学 铁二核分化和囊肿重新激活。总之，我们的实验将在 了解调节发展开关的力学和调节 疾病。