Does a Drosophila Melanogaster Mutant Exhibit a General Defect in MicroRNA-Mediated Gene Silencing?

Mature microRNAs (miRNA) are ~22 nucleotide long single-stranded ribonucleic acids encoded by the genome and essential for gene silencing. Silencing occurs when miRNAs are processed and subsequently associate with the miRNA-induced silencing complex (miRISC). miRISC binds via complementary base pairing to target mRNAs, and target mRNAs are silenced by either mRNA degradation, translational block, or both. microRNA-based therapeutics are being developed and deployed to treat diseases caused by altered gene expression.We aim to characterize the molecular mechanisms of microRNA-mediated gene silencing. We have Drosophila melanogaster mutant fly lines with disrupted gene silencing as visualized by a GFP-based fluorescent reporter of silencing. We are now curious as to whether the observed change in fluorescence is the result of a disruption to microRNA-mediated gene silencing in general, or if the observed change in fluorescence reflects a disruption of a subset of microRNAs or microRNA targets. We are building fly lines and appropriate controls that will enable us to test for changes in microRNA-mediated gene silencing using a different and vetted reporter of gene silencing that is active in developing neurons. Recent efforts have introduced the nerfin-GFP sensor into our mutant fly line and a control line, setting the stage for comparative analysis of gene silencing.