RNA Processing in Trypanosome Mitochondria

智力优势：锥虫是一种含有独特线粒体基因组的着丝体原生动物，称为着丝体（kDNA）。当kDNA内的基因表达时，相应的信使rna在数百个小向导rna （gRNAs）的指导下被广泛编辑。本项目关注这些grna的成熟。前体RNA分子被合成，包括多个grna，这些前体在编辑之前被未知的机制和酶处理。本研究鉴定了一种名为mRPN1（线粒体RNA前体加工内切酶1）的新型酶，该酶是布鲁氏锥虫高效gRNA生物生成所必需的。mRPN1切割双链RNA的特异性让人想起细菌RNase III和真核生物Dicer，它与三个蛋白质亚基形成复合物，这被认为有助于gRNA进入RNA编辑途径。mRPN1及其相关亚基在mRPN1复合体中的作用将被研究。由于gRNA生物发生在锥虫RNA生物学中几乎是一个未开发的领域，这些研究应该在早期分化的着丝质体中开辟新的问题和潜在的新范式。更广泛的影响：这项研究涉及德克萨斯农工大学和其他机构的一个强大的合作者团队，其教育成分直接影响到一名少数民族研究生、一名博士后和一名本科生。研究结果将通过在著名研究期刊上以及在当地和国际会议上发表数据的方式传达给科学界。mRPN1及其参与gRNA生物发生的发现在2011年春季的Gordon RNA编辑研究会议和着丝质体分子细胞生物学会议上均有报道。

Intellectual merit: Trypanosomes are kinetoplastid protozoa that contain a unique mitochondrial genome known as the kinetoplast (kDNA). When genes within the kDNA are expressed, the corresponding messenger RNAs that are synthesized are extensively edited in reactions directed by hundreds of small guide RNAs (gRNAs). This project concerns the maturation of these gRNAs. Precursor RNA molecules are synthesized that include multiple gRNAs, and these precursors are processed by unknown mechanisms and enzymes that precede editing. This research characterizes a novel enzyme termed mRPN1 (mitochondrial RNA precursor-processing endonuclease 1), which is required for efficient gRNA biogenesis in Trypanosoma brucei. mRPN1 cleaves double-stranded RNA with a specificity that is reminiscent of bacterial RNase III and eukaryotic Dicer, and it forms a complex with three protein subunits, which is thought to facilitate entry of gRNA into the RNA editing pathway. The role of mRPN1 and its associated subunits in the mRPN1 complex will be investigated. Since gRNA biogenesis is virtually an unexplored field in trypanosome RNA biology, these studies should open new questions and potentially new paradigms in early divergent kinetoplastids. Broader impacts: This research involves a strong team of collaborators at Texas A&M and other institutions, and its educational component directly impacts a graduate student, who is an ethnic minority, a postdoctoral fellow, and an undergraduate student. The findings will be communicated to the scientific community through the publication of data in prominent research journals, and at local and international meetings. The discovery of mRPN1 and its involvement in gRNA biogenesis was reported in the spring 2011 at both the Gordon Research Conference on RNA editing and the Kinetoplastid Molecular Cell Biology Meeting.