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世界各地发展中国家的主要疾病。在这些地区，目前有100,000人感染了锥虫。人类疾病包括非洲锥虫病（“睡眠疾病”），查加斯疾病（南美洲地区的地方性）以及皮肤，毛眼和内脏利什曼病（中东部分地区和印度次大陆的部分地区）。非洲锥虫病被带有锥虫菌的brucei亚种的采摘蝇传播到人类。世界卫生组织估计该疾病负担为205万残疾人的生活年。治疗成本很高，未经治疗的感染通常会导致死亡。但是，锥虫相互共享许多代谢途径，这些途径与人类途径有足够的差异，以便在与当前可用的疗法更有效的治疗剂开发中受到利用。观察到的一种可能的治疗方法是，锥虫以不同形式出现在其人类和昆虫宿主中。在生命周期的各个阶段，这些不同的形式可能反映了mRNA稳定性的差异。该建议的目的是了解如何在锥虫中代谢mRNA。在这些寄生虫中，稳态水平mRNA的转录调节似乎很少。因此，在一种生命周期形式中不同mRNA之间存在的mRNA稳定性差异可以部分通过差异mRNA衰变来调节。不同生命周期形式之间mRNA表达模式的差异也可能部分通过差异mRNA更新来控制。我们建议识别并表征在mRNA衰减中重要的两种至关重要的酶促活性。我们的目的是（1）纯化和克隆锥虫的去氨酶； （2）从锥虫中纯化和克隆脱烯基核酸酶； （3）评估在体内mRNA转换中的depapping酶和denenylase的作用。我们最近开发了一个无细胞的系统，该系统具有这两种酶促活性的胜任。这项工作是我们提出的实验计划中的关键第一步。