Research Projects

Ageing is by far the largest known risk factor for numerous prevalent noncommunicable diseases, yet the molecular mechanisms underlying this process are largely unknown. To understand the relationship between age-related diseases and normal ageing, it is crucial to characterize the regulatory mechanisms that integrate tissue function with the physiology of the whole organism. Emerging evidence from diverse model organisms has implicated non-coding Ribonucleic acids (ncRNAs) and RNA binding proteins (RBPs) as critical components of signaling pathways that regulate lifespan by regulating mRNA turnover and translation. Work from my laboratory and that of others have linked aberrant microRNA (miRNA) expression to ageing and age-related pathologies. These studies have emphasized the importance of post-transcriptional mechanisms (mediated by RBPs) in ensuring tight control of miRNA biogenesis. Our recent work has also highlighted the importance of cis-acting elements such as terminal loops and stem-base in the differential expression of clustered miRNAs. In this study, we propose to characterize the role of RBPs that regulate miRNA biogenesis during ageing. Our proteomic analysis has identified conserved RBPs that physically interact with the terminal loops of precursors of three highly conserved miRNAs encoded by the let-7-Complex locus in Drosophila. Building on these findings, we will combine in vitro approaches (RNA gel shifts, in vitro processing, and RNA immunoprecipitation) with genetic (RNAi screen) and molecular approaches (mutational analysis) to systematically characterize the role of these RBPs in modulating lifespan and healthspan in Drosophila melanogaster. In Aim 1, we will screen for RNA-binding proteins that regulate mature miRNA biogenesis using a dual fluorescent reporter-based system. In Aim 2, we will perform in vitro assays (Drosha processing, Dicer processing, RNA gel shifts) to examine which processing step (Drosha or Dicer) is influenced by the RBPs identified in Aim 1 and by our preliminary proteomic analysis. In Aim 3, we will assess the impact of modulating the levels of the top candidate RBPs in ageing and age-related disease models. Taken together, these analyses will identify new miRNA biogenesis factors and provide insights into the role of RBPs in longevity pathways. Furthermore, this work will lay the foundation for investigating the longevity roles of these RBPs in other species. Finally, the long-term goal of this work is to contribute to the rational design of strategies that can be utilized to modify gene expression for the treatment and prevention of age-related diseases.