Current and recent members of the Van Vactor and Perrimon laboratories at HMS have created a transgenic resource to allow conditional analysis of in vivo functions for over 140 microRNA genes in Drosophila with spatial and temporal precision. This resource, just published in Nature Communications, represents a highly collaborative project that will open the door to a broad variety of novel functional screens. Using this toolkit to explore the landscape of regulatory function in muscle tissue, they discovered a dozen microRNAs required for the maintenance of flight muscle form and function, suggesting that post-transcriptional mechanisms may be vital for protecting muscle from degeneration.