Mechanisms of Small RNA-Mediated Silencing in Chlamydomonas

RNA干扰（RNAi）是一种调节基因表达的细胞过程，是植物和动物的防御系统。该途径依赖于小rna （sRNAs）来识别靶标，然后被各种分子机制抑制。微藻是生产多种生物材料和营养品的重要和可持续的原料，但由于对其如何控制基因表达和代谢的知识有限，其生产力的提高受到限制。该项目将有助于我们理解srna在微藻中的作用，并有助于开发实际应用的RNAi工具（例如基于RNAi的藻类大规模培养作物保护策略）。该研究还将有助于培养本科生和研究生以及一名博士后。通过参加内布拉斯加大学林肯分校的几个教育项目，将招收来自科学领域代表性不足群体的学生、潜在的第一代大学生或有经济需求的学生。真核生物中sRNA功能的几个方面，特别是sRNA如何介导翻译抑制，仍然知之甚少。一个关键的问题是对srna效应复合物的成分及其在响应内部发育程序和/或外部线索时的潜在调节的不完全了解。该项目将提供sRNA功能方面的见解，特别是多核糖体相关转录物的翻译抑制。在莱茵衣藻（Chlamydomonas reinhardtii）中，果蝇VASA内含子基因（VIG）的同源物参与了该过程。该研究将：(i)通过几种蛋白质组学方法表征VIG和Argonaute效应复合物在srna介导的翻译抑制中的相互作用；（ii）通过插入突变筛选分离参与srna介导的翻译抑制的其他基因；（iii）表征一类新的衣藻sRNAs的生物发生和潜在功能，其长度与后生动物piwi相互作用rna相似。由于srna介导的多核糖体mrna的抑制也发生在陆地植物和动物中，因此该结果可能有助于我们理解真核生物中srna介导的表观遗传机制的进化（即保守与分化）。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

RNA interference (RNAi) is a cellular process that regulates gene expression and acts as a defense system in plants and animals. This pathway relies on small RNAs (sRNAs) to identify targets, which are then suppressed by a variety of molecular mechanisms. Microalgae are an important and sustainable feedstock for producing diverse biomaterials and nutraceuticals, but improving their productivity is constrained by limited knowledge of how they control gene expression and metabolism. This project will contribute to our understanding of the role of sRNAs in microalgae and to the development of RNAi tools for practical applications (such as RNAi-based crop protection strategies for algal mass culturing). The research will also contribute to the training of undergraduate and graduate students and one postdoctoral fellow. Recruitment of students from underrepresented groups in the sciences, potential first-generation college students, or those that have financial needs will be enabled by participation in several educational programs at the University of Nebraska-Lincoln.Several aspects of sRNA function in eukaryotes, particularly how sRNAs mediate translational repression, remain poorly understood. One key problem is an incomplete knowledge of the components of sRNA-effector complexes and their potential modulation in response to internal developmental programs and/or external cues. This project will provide insight into aspects of sRNA function, particularly the translation repression of polyribosome-associated transcripts. In the alga Chlamydomonas reinhardtii, a homolog of the Drosophila VASA INTRONIC GENE (VIG) is involved in this process. The research will: (i) characterize the interplay between VIG and Argonaute effector complexes in sRNA-mediated translation repression by several proteomic approaches; (ii) isolate additional genes involved in sRNA-mediated translation repression by using an insertional mutagenesis screen; and (iii) characterize the biogenesis and potential function of a novel class of Chlamydomonas sRNAs, similar in length to the metazoan PIWI-interacting RNAs. Since sRNA-mediated repression of polyribosomal mRNAs also occurs in land plants and animals, the results may contribute to our understanding of the evolution (i.e., conservation vs. divergence) of sRNA-mediated epigenetic mechanisms in eukaryotes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.