Determine the spatial and temporal expression patterns of Drosophila miRNAs

microRNAs (miRNAs), are a class of small (21-23nt), endogenous, non-coding RNAs which regulate gene expression. In animals, most miRNAs recognize their mRNA targets though imperfect base paring with complementary sites at the 3’UTR of the mRNAs, resulting in translational repression of the target genes. The specific functions of miRNAs in Drosophila are generally unknown. To determine the spatial and temporal expression patterns of miRNAs, it is necessary to identify both the sites and time of miRNA action and further elucidate miRNA functions. I made a series of GFP reporter transgenes (miRNA sensors) in UAS vector containing multiple copies of synthesized miRNA targets in the 3’UTR. The sensors were expressed in a range of tissues driven by different GAL4 drivers. We expected that our sensors would reveal when and where miRNAs are actively regulate gene expression. However, the sensor strategy failed to detect clear expression patterns of the miRNAs we tried.