SMALL RNAS AND THEIR ROLE IN TRYPANOSOME BIOLOGY

小 RNA 及其在锥虫生物学中的作用

• 批准号: 7558950
• 负责人: ELISABETTA ULLU
• 金额: $ 37.24万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7558950
• 关键词: Africa South of the Sahara; African; African Trypanosomiasis; Animal Disease Models; Biogenesis; Biology; Blood Circulation; Chromosome Segregation; Chromosome Structures; Clinical Trials; Collaborations; DNA biosynthesis; Development; Disease; Drug Delivery Systems; Enzymes; Family; Foundations; Funding; Gene Expression Regulation; Genes; Heterochromatin; Kinetoplast DNA; Laboratories; Leishmania; Leishmania braziliensis; Mining; Mitochondria; Organelles; Parasites; Pathogenesis; Pathway interactions; Pharmaceutical Preparations; Proteins; Protozoa; RNA Interference; Relative (related person); Research; Role; Site; Small Interfering RNA; Small RNA; Staging; Technology; Trypanosoma; Trypanosoma brucei brucei; human disease; mRNA Transcript Degradation; mouse model; research study; stem; stem cell fate; tool

DESCRIPTION (provided by applicant): African trypanosomes cause disease and suffering in vast regions of sub-Saharan Africa and the drugs available to eliminate the disease are sub-optimal, to say the least. Many laboratories, including our own, have been engaged in studying the biology of Trypanosoma brucei and have contributed to the understanding of several mechanisms that are unique to trypanosomes. The discovery of trypanosome-specific pathways is the first step towards identifying new potential drug targets, which may be exploited against the parasite itself. Since 1998 when we discovered the RNAi pathway in Trypanosoma brucei our research has focused towards understanding the mechanism and components of RNAi. These studies are essential to eventually attempt to use small RNAs as drugs against trypanosomes. This possibility is not without foundation, since there are already several clinical trials in place to use small RNAs to cure certain human diseases. The experiments we propose stem directly from three main findings generated during the last funding period. First, sequencing of small interfering RNAs (siRNAs), from both bloodstream and procyclic trypanosomes has revealed a new target of the RNAi pathway, namely a family of satellite-like repeats (CIR147) located at chromosomal internal sites. These repeats may function in some aspect of chromosome structure and/or regulation of gene expression. Second, we have identified the RNAi genes in Leishmania braziliensis and in collaboration with Steve Beverley have demonstrated that the RNAi pathway is operational. However, L brasiliensis has some limitations for studying pathogenesis because at present there is no suitable small animal model of the disease. In contrast, Diane McMahon-Pratt at Yale has established a mouse model for L. panamensis, a close relative of L. brasiliensis, which also has the RNAi genes. Thus, our findings open the way to establish tools for applying the wonders of RNAi technology to the study of different aspects of the biology and pathogenesis of Leishmania. Third, we have discovered that a second T. brucei Argonaute-like protein (termed PiwiS) is localized in the mitochondrion and forms foci reminiscent of the antipodal sites where some enzymes for kinetoplast DNA (kDNA) replication localize, implicating PiwiS in some aspect of kDNA biogenesis. In the last few years Argonaute proteins have emerged as central regulators of an outstandingly wide range of phenomena, both at the transcriptional and post-transcriptional levels. Thus, we hypothesize that PiwiS functions in some aspect of RNA silencing in the mitochondrion. It should be noted that this protein is the first example of an Argonaute protein that localizes to an organelle. Our specific aims for the next funding period are: 1. To further mine the biology of trypanosomatids through high-throughput sequencing of small RNAs from T. brucei and from L. braziliensis, and through the functional and structural characterization of the CIR147 satellite-like repeat family. 2. To establish tools for heritable and regulated RNAi in L. panamensis. 3. To establish the function of PiwiS in the T. brucei mitochondrion. Project Narrative: African trypanosomes cause disease and suffering in vast regions of sub-Saharan Africa and the drugs available to eliminate the disease are sub-optimal, to say the least. Our research has focused towards understanding the mechanism and components of RNA interference to eventually attempt to use small RNAs as drugs against trypanosomes. This possibility is not without foundation, since there are already several clinical trials in place to use small RNAs to cure certain human diseases.

描述（由申请人提供）：至少可以说，至少可以说，非洲锥虫在撒哈拉以南非洲的广阔地区引起疾病和苦难，至少可以说，可以消除这种疾病的疾病。许多实验室，包括我们自己的实验室，一直在研究Brucei锥虫的生物学，并为理解锥虫独有的几种机制做出了贡献。锥虫特异性途径的发现是识别新的潜在药物靶标的第一步，这可能会针对寄生虫本身。自1998年我们发现Brucei锥虫瘤的RNAi途径以来，我们的研究一直致力于理解RNAi的机制和组成部分。这些研究对于最终尝试使用小RNA作为针对锥虫的药物至关重要。这种可能性并非没有基础，因为已经进行了几项临床试验，可以使用小型RNA治愈某些人类疾病。我们提出的实验直接源于最后一个资金期间产生的三个主要发现。首先，来自血液和procyclic锥虫的小干扰RNA（siRNA）的测序揭示了RNAi途径的新靶标，即位于染色体内部位置的卫星样重复量（CIR147）家族。这些重复可能在染色体结构的某些方面和/或基因表达的调节中起作用。其次，我们已经确定了巴西利什曼原虫的RNAi基因，并与史蒂夫·贝弗利（Steve Beverley）合作证明了RNAi途径是运营的。然而，巴西利氏菌在研究发病机理上有一些局限性，因为目前尚无适当的小动物模型。相比之下，耶鲁大学的黛安·麦克马洪·普拉特（Diane McMahon-Pratt）建立了一个小鼠Panamensis的小鼠模型，L. panamensis是Brasiliensis的近亲，该模型也具有RNAi基因。因此，我们的发现为建立将RNAi技术的奇观的工具开辟了道路，以研究利什曼尼亚生物学和发病机理的不同方面。第三，我们发现第二个T. brucei argonaute样蛋白（称为PIWIS）位于线粒体和形成焦点中，让人联想到抗虫位点，其中一些动力学DNA（KDNA）复制的酶本地化了一些酶，暗示了piwis，在KDNA Biogenses的某些方面暗示了Piwis。在过去的几年中，Argonaute蛋白已成为转录和转录后水平的范围广泛现象的中心调节剂。因此，我们假设PIWI在线粒体中的RNA沉默的某些方面起作用。应该注意的是，该蛋白是定位于细胞器的Argonaute蛋白的第一个例子。我们在下一个资金期间的具体目的是：1。通过对来自T. brucei和巴西L. Braziliensis的小型RNA的高通量测序进一步挖掘锥形的生物学，并通过CIR147卫星类似于CIR147卫星的功能和结构表征。 2。为L. Panamensis建立可遗传和受管制的RNAi的工具。 3。建立PIWIS在Brucei线粒体中的功能。 项目叙述：非洲锥虫在撒哈拉以南非洲的广阔地区引起疾病和苦难，至少可以说，可以消除这种疾病的药物是最佳的。我们的研究集中于理解RNA干扰的机制和组成部分，以最终尝试将小RNA用作抗锥虫的药物。这种可能性并非没有基础，因为已经进行了几项临床试验，可以使用小型RNA治愈某些人类疾病。