Intellectual Merit: Small RNAs, including microRNAs (miRNAs) and small interfering RNAs (siRNAs), are key regulators of many biological processes. Several RNA-binding proteins involved in general RNA metabolism are known to play important roles in regulating miRNA biogenesis. A challenge is to understand how RNA binding proteins affect miRNA biogenesis, as well as how the miRNA processing machinery interconnects with general RNA metabolism. This research targets these knowledge gaps. Preliminary studies demonstrated that DAWDLE (DDL), an RNA binding protein from Arabidopsis, is required for the accumulation of a subset of miRNAs and siRNAs. DDL interacts with pri-miRNA (precursor of miRNAs) and DCL1 (the processor of pri-miRNA) and positively regulates pri-miRNA processing. We hypothesize that DDL facilitates DCL1 to access and/or process a subset of pri-miRNAs. Specific objectives are to: 1) Analyze the role of DDL in miRNA biogenesis; 2) Analyze the function of protein domains of DDL in pri-miRNA processing; and 3) Analyze the role of DDL in siRNA biogenesis. This research will advance knowledge of processes leading to small RNA accumulation, which in turn will improve future efforts at elucidating the biological processes involving small RNAs and to refine small RNA-based technology that has been used to improve agricultural production and human health.
Broader Impacts: This research will provide training for a postdoctoral researcher, a graduate student, undergraduate students, and high school students. The PI is a faculty sponsor/mentor for students participating in the Nebraska EPSCoR-supported Young Nebraska Scientists program, which fosters research exposure and participation by underrepresented minority high school students, and in the University of Nebraska-Lincoln Undergraduate Creative Activities and Research Experiences (UCARE) program. In addition, the PI pursues active collaborations with faculty at local liberal arts colleges to help reach students that may not have ready opportunity for research experiences. The PI is also integrating his latest research into a new course, "RNA Silencing", offered to upper level undergraduate and graduate students.