Identification and Characterization of Novel FMRP-Associated miRNAs

New evidence suggests that Fragile X Mental Retardation Protein (FMRP) may need to associate with ancillary factors to co-regulate the production of some of important synaptic proteins. Currently, there is a critical need to characterize these molecules. Some factors believed to associate with FMRP and co-regulate target mRNAs include a group of small regulatory molecules called microRNAs (miRNAs). There were two goals associated with this project. First, to use an established model system for FXS to identify and functionally characterize all FMRP-associated miRNAs and mRNAs involved in the control of synapse structure and function. Second, to investigate the molecular mechanisms involved in coordinated FMRP- and miRNA-mediated translational regulation. Progress towards both of these goals has shed light on the molecular pathogenesis of FXS. Progress towards completion of aims: First, after significant setbacks developing novel transgenic epitope-tagged FMRP protein that works efficiently in vivo, we have adapted and optimized in vitro approaches to efficiently enrich for and purify FMRP-associated miRNAs and mRNAs. These RNAs still need to be sequenced. Second, a serendipitous discovery as allowed us to make substantial progress towards understanding the molecular mechanisms involved in FMRP-mediated recruitment of miRNAs to target mRNAs. This will allow us to very rapidly and efficiently validate bona fide target mRNAs. Importantly, both findings provided strong preliminary data for a recent grant submission to NIH. The original document contains color images.