Collaborative Research: RNA processing in trypanosome mitochondria

该项目将研究一种称为锥虫的古老单细胞寄生虫的独特基因表达机制。与大多数使用从DNA复制的RNA“原样”指导蛋白质合成的生物不同，在锥虫（和其他生物）的能量产生线粒体中，RNA通过添加或删除特定信息进行编辑。编辑发生的原因尚不清楚，但了解它是如何发生的可能会为这种类型的遗传改变的功能提供重要线索。该项目将通过为博士后、研究生、本科生和高中生提供跨学科培训机会，产生广泛的教育影响。 此外，具体的努力将针对传统上在STEM学科中代表性不足的群体的学生。 本项目主要研究锥虫线粒体中RNA编辑的过程。通过一种称为RECC的中央编辑酶的作用，尿苷酸在数十种mRNA中的数千个特定位点插入或删除。这个广泛的编辑过程由数百个小的非编码向导RNA指导，并涉及几个辅助因子。然而，编辑调节的机制基础仍然是锥虫RNA生物学中一个长期存在的问题。在以前的工作中，一种称为REH2C的调节编辑亚复合物被鉴定并发现含有三个蛋白质亚基。 其中两个，解旋酶和锌指蛋白，似乎直接参与编辑。遗传学、生物化学、生物信息学和蛋白质组学方法的组合将用于解决这些蛋白质如何与mRNA组装并引导mRNA在体内形成编辑体复合物以及复合物如何执行编辑功能。这些研究可能为RNA编辑调控建立新的范式。从更广泛的意义上说，这些研究将使我们更好地了解这个惊人的过程是如何演变的。这个系统可以用来与相关的RNA解旋酶和RNA过程进行类比，这些RNA解旋酶和RNA过程由小向导RNA指导，并且最近在真核细胞谱系中进化。

This project will study a unique mechanism of gene expression in ancient single-celled parasites called trypanosomes. Unlike most organisms that use the RNA copied from DNA "as is" for directing protein synthesis, in the energy-generating mitochondria of trypanosomes (and other organisms), the RNA is edited by addition or removal of specific information. Why editing occurs is not clear, but understanding how it happens may provide important clues about the function of this type of genetic alteration. The project will have broad educational impact by providing interdisciplinary training opportunities for postdoctoral, graduate, undergraduate, and high school students. In addition, specific efforts will target students from groups traditionally underrepresented in the STEM disciplines. This project focuses on the process of RNA editing in the mitochondria of trypanosomes. Through the action of a central editing enzyme, called RECC, uridylates are inserted or deleted at thousands of specific sites in dozens of mRNAs. This extensive editing process is directed by hundreds of small non-coding guide RNAs and involves several auxiliary factors. However, the mechanistic basis of the regulation of editing remains a long-standing question in trypanosomal RNA biology. In previous work, a regulatory editing subcomplex, called REH2C, was identified and found to contain three protein subunits. Two of these, a helicase and a zinc-finger protein, appear to participate directly in editing. A combination of genetic, biochemical, bioinformatics, and proteomic approaches will be used to address how these proteins assemble with mRNAs and guide mRNAs into editosome complexes in vivo and how the complexes carry out editing functions. These studies may establish new paradigms in RNA editing regulation. In a broader sense, the studies will allow a better understanding of how this amazing process evolved. This system can be used to draw analogies with related RNA helicases and RNA processes that are directed by small guide RNAs and that evolved more recently in eukaryotic lineages.