Final Report Summary - FRONTIERS OF RNAI-II (High resolution and chemical genetic approaches to RNA silencing mechanisms) Silencing small RNAs are universal regulators of gene expression in a multitude of organisms, yet how these molecules function in space and time within the complex mosaics formed by the many discount cell types of tissues/organs remains largely unknown. Using the plant root tip as a model organ, we have successfully addressed this question for the first time in any organism. We could implement a user-friendly browser that helps researchers interrogate the spatial relationships between the small RNAs present in each individual cells of the root and the status of the genes regulated by these small RNAs. This establishes a proof-of-concept for other organisms. In the meantime, other aspects of the project, also completed successfully, have helped us better understand how small RNAs are made within the cells and how they execute their functions. Finally, we have isolated chemical compounds that enable us to modulate in adult plants, the activity of small RNAs, of which some hold antiviral potentials.
