Regulation of mRNA Turnover in Trypanosomes

锥虫中 mRNA 周转的调节

• 批准号: 6989746
• 负责人: Vivian Bellofatto
• 金额: $ 26.57万
• 依托单位: UNIV OF MED/DENT OF NJ-NJ MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-12-01 至 2008-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6989746
• 关键词: RNA interference; Trypanosoma; enzyme activity; enzyme mechanism; gene expression; genetic regulation; leishmaniasis; messenger RNA; nuclease; nucleic acid metabolism; nucleic acid purification; posttranscriptional RNA processing; protozoal genetics; trypanosomiasis

DESCRIPTION (provided by applicant): Trypanosomiasis and Leishmaniasis are major diseases in developing countries throughout the world. In these areas 100,000 people are currently infected with trypanosomes. Human illness includes African trypanosomiasis ("sleeping sickness"), Chagas' disease (endemic in regions of South and Central America) and cutaneous, mucocutaneous and visceral Leishmaniasis (endemic in parts of the Middle East and the Indian Subcontinent). African trypanosomiasis is spread to humans by the bite of tsetse flies that harbor the Trypanosoma brucei subspecies. The disease burden is estimated by the World Health Organization to be 2.05 million Disability Adjusted Life Years. The cost of treatment is high, and untreated infection usually results in death. However, trypanosomatids share many metabolic pathways among themselves that differ enough from human pathways to be exploited in the development of therapeutics that are more efficacious than those currently available. One possible therapeutic approach is suggested by the observation that trypanosomatids occur in different forms in their human and insect hosts. These differing forms at various stages of the life cycle may reflect differences in mRNA stability. The purpose of this proposal is to gain an understanding of how mRNAs are metabolized in trypanosomes. There appears to be little transcriptional regulation of steady state levels mRNA in these parasites. Therefore, the differences in mRNA stability that exist among different mRNAs in one life cycle form may be regulated, in part, by differential mRNA decay. Differences in mRNA expression patterns among the different life cycle forms is also likely to be controlled, in part, by differential mRNA turnover. We propose to identify and characterize two crucial enzymatic activities important in mRNA decay. Our aims are (1) to purify and clone the decapping enzyme from trypanosomes; (2) to purify and clone the deadenylating nuclease from trypanosomes; and (3) to assess the roles of the decapping enzyme and deadenylase in mRNA turnover in vivo. We have recently developed a cell-free system that is competent for both of these enzymatic activities. This work is a key first step in our proposed experimental plan.

描述（由申请人提供）： 锥虫病和利什曼病是全世界发展中国家的主要疾病。目前这些地区有 10 万人感染锥虫。人类疾病包括非洲锥虫病（“昏睡病”）、恰加斯病（南美洲和中美洲地区流行）以及皮肤、粘膜和内脏利什曼病（中东和印度次大陆部分地区流行）。非洲锥虫病通过携带布氏锥虫亚种的采采蝇叮咬传播给人类。据世界卫生组织估计，疾病负担为 205 万残疾调整生命年。治疗费用很高，未经治疗的感染通常会导致死亡。然而，锥虫类动物之间共享许多代谢途径，这些途径与人类途径有很大不同，可用于开发比现有疗法更有效的疗法。观察到锥虫在人类和昆虫宿主中以不同的形式出现，提出了一种可能的治疗方法。生命周期不同阶段的这些不同形式可能反映了 mRNA 稳定性的差异。该提案的目的是了解 mRNA 在锥虫中的代谢方式。这些寄生虫中稳态水平 mRNA 的转录调控似乎很少。因此，一种生命周期形式中不同 mRNA 之间存在的 mRNA 稳定性差异可能部分受到不同 mRNA 衰减的调节。不同生命周期形式之间 mRNA 表达模式的差异也可能部分受到差异 mRNA 更新的控制。我们建议鉴定和表征在 mRNA 降解中重要的两种关键酶活性。我们的目标是（1）从锥虫中纯化和克隆脱帽酶； (2)从锥虫中纯化并克隆去腺苷酸核酸酶； (3)评估脱帽酶和去腺苷酸酶在体内mRNA转换中的作用。我们最近开发了一种能够进行这两种酶活性的无细胞系统。这项工作是我们提出的实验计划中关键的第一步。