The project will have broad scientific impact by generating basic knowledge needed for the genetic improvement of microalgae, which are emerging as a suitable resource for the production of biomaterials, nutraceuticals, and biofuels. The specific focus of the work will be on understanding how small RNA molecules regulate the process of protein synthesis, using a unicellular green alga as the model. The research will involve researchers at undergraduate, graduate and postdoctoral levels, thus contributing to the training of 'knowledge workers' whose specialized skills will enable them to work productively within STEM industries and occupations. Results and products will be disseminated broadly through publication in scientific journals, outreach activities, and contributions to an algal resource center. The project will also broaden participation through the recruitment and education of members of underrepresented groups in the sciences and first generation students.
Small RNAs play important regulatory roles in multiple processes, and RNA interference (RNAi) has become a valuable tool for reverse genetic studies and practical applications in medicine and agriculture. Whereas many aspects of small RNA function have been studied in detail, the mechanisms of small RNA-mediated translational repression remain poorly understood. This project will address this gap in understanding by studying how small RNAs function to inhibit protein synthesis at post-initiation steps. The experiments will be carried out in a unicellular green alga, Chlamydomonas. In preliminary experiments, a genetic screen for mutants impaired in small RNA-mediated translational repression identified genes involved in TOR (Target of Rapamycin) signaling and polypeptide prenylation pathways, thus implicating these processes as key steps in small RNA-mediated function. To follow up on these observations, experiments will be conducted to: (i) characterize the negative interplay between RAPTOR (Regulatory Associated Protein of Target Of Rapamycin) and the TOR kinase with RNAi effector complexes, mostly through proteomic approaches; (ii) characterize a mutant deleted for a homolog of the Vasa Intronic Gene (VIG) product, via the identification of VIG interactors and their effect(s) on ribosome function; and (iii) identify new factors required for sRNA-mediated translation repression, by means of an insertional mutagenesis screen. The findings are expected to provide new insights into how small RNAs function in translational repression.
