Transcriptional mechanisms in Toxoplasma gondii

弓形虫的转录机制

• 批准号: 7187070
• 负责人: Michael W White
• 金额: $ 21.23万
• 依托单位: MONTANA STATE UNIVERSITY - BOZEMAN
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-15 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7187070
• 关键词: Address; Aging; Apicomplexa; BAG1 gene; Base Sequence; Binding; Binding Proteins; Biochemical; Biochemical Genetics; Biological Assay; Cessation of life; Chromosomes; Chronic; Cloning; Code; Consensus; Cyst; DNA-Binding Proteins; DNase-I Footprinting; Development; Drug toxicity; EMSA; Elements; Event; Exploratory/Developmental Grant for Diagnostic Cancer Imaging; Exposure to; Food; Funding; Gene Expression; Gene Expression Profile; Genes; Genome; Goals; Grant; Immune system; Individual; Infection; Lead; Life; Life Cycle Stages; Listeria; Luciferases; Mediating; Methods; Molecular; Parasite Control; Parasites; Pregnancy; Proteins; Public Health; Risk; Salmonella; Source; Specificity; Staging; Techniques; Time; Tissues; Toxoplasma; Toxoplasma gondii; Toxoplasmosis; Women AIDS; base; chemotherapy; cis acting element; foodborne; hazard; human BAG1 protein; novel; novel strategies; nucleoside triphosphatase; pathogen; prevent; promoter; research study; transcription factor; yeast genetics

DESCRIPTION (provided by applicant): Toxoplasma gondii infections are a public health hazard for millions of individuals that contact this pathogen annually, particularly those with immune systems weakened by aging, chemotherapy or AIDS; and women that acquire the infection during pregnancy. Exposure to this pathogen occurs through contact with environmental sources and contaminated food ranking T. gondii only behind bacterial pathogens, Listeria and Salmonella, as the third-leading cause of food-borne death. No current therapy is able to prevent life- time infections caused by the encysted bradyzoite stage and drug toxicity limits long-term treatment for at risk individuals. Thus, there is a critical need to develop new approaches capable of preventing chronic Toxoplasma infection, although achieving this goal is hampered by a lack of understanding of the molecular basis for tissue cyst formation. Recently, we have completed a comprehensive SAGE analysis (funded by R21 award AI53815) of the transcriptome of the Toxoplasma intermediate life cycle. These studies demonstrate primary developmental transitions leading to tissue cyst formation are accompanied by a temporally ordered set of transcriptional events from genes that are dispersed across all parasite chromosomes, and are therefore, co-regulated by trans-acting protein factors. This exploratory grant seeks to gain a greater understanding of the core transcriptional mechanisms associated with parasite development by characterizing the nucleotide sequence elements and identifying the protein factors involved in the expression of known and novel bradyzoite-specific genes. We have developed dual- luciferase assays based on high-throughput cloning methods to functionally demonstrate that the control of tachyzoite- and bradyzoite-specific gene expression requires gene proximal sequences lying upstream of coding regions in the Toxoplasma genome. In this proposal, we will employ these same methods to define the minimal sequence requirements for five bradyzoite promoters, and in turn, use this information to identify the appropriate DNA binding proteins through biochemical and genetic strategies. The studies proposed here will address a fundamental gap in our understanding how Toxoplasma parasites (and other Apicomplexa) regulate gene expression, and will ultimately, lead to a better understanding of how these parasites control development into the clinically important tissue cyst.

描述（由申请人提供）：弓形虫弓形虫感染是每年接触这种病原体的数百万个人的公共卫生危害，尤其是那些因衰老，化学疗法或艾滋病而削弱的免疫系统的人；以及怀孕期间感染的妇女。暴露于这种病原体是通过与环境源接触和仅在细菌病原体，李斯特菌和沙门氏菌后面的gondii污染的食物等级的接触而发生的，这是食源性死亡的第三个主要原因。目前的疗法无法防止由百科氏菌阶段和药物毒性限制在风险个体的长期治疗中引起的生命感染。因此，迫切需要开发能够预防慢性毒素感染的新方法，尽管由于缺乏对组织囊肿形成的分子基础的了解，无法实现这一目标。最近，我们完成了毒素中间生命周期的转录组的全面鼠尾草分析（由R21奖AI53815资助）。这些研究表明，导致组织囊肿形成的主要发育过渡伴随着从分散在所有寄生虫染色体中的基因的时间有序的转录事件集，因此，通过跨性蛋白质因子共同调节。该探索性赠款旨在通过表征核苷酸序列元素并识别与已知和新型Bradyzoite特异性基因表达所涉及的蛋白质因子来更深入地了解与寄生虫发育相关的核心转录机制。我们已经基于高通量克隆方法开发了双重荧光素酶测定，以表明对tachyzoite-和bradyzoite特异性基因表达的控制需要弓形虫基因组中编码区上的基因近端序列。在此提案中，我们将采用这些相同的方法来定义五个bradyzoite启动子的最小序列要求，然后使用此信息通过生化和遗传策略来识别适当的DNA结合蛋白。此处提出的研究将解决我们理解弓形虫寄生虫（和其他Apicomplexa）如何调节基因表达的基本差距，并最终将更好地理解这些寄生虫如何控制临床重要的组织囊肿。