HLA-C and myotonic dystrophy type 1: As we were not interested in a complete description of muscleblind regulation by microRNAs but in providing proof of concept of their usefulness as therapeutic targets in DM1, we continued our studies with the two confirmed muscleblind regulators; miR-277 and miR-304. To assess the efficiency of miRNA downregulation by driving sponge constructs with the Mhc-Gal4 driver, we performed qRT-PCRs to detect the levels of the corresponding RNAs and confirmed that flies expressing miR-277SP or miR-304SP had reduced levels of the corresponding microRNA (Fig. 1b,c).