Loss of Antp function in Drosophila flight muscle precursors : RNAi in larval wing disc-associated myoblasts

Muscle development and diversity require a large number of spatially and temporally regulated events controlled by transcription factors (TFs). Drosophila has long stood as a model organism to study myogenesis due to the highly conserved key TFs involved at all stages of muscle development, from specification to differentiation. While many studies focused on the diversification of Drosophila larval musculature, how distinct adult muscle types are generated is much less characterised. Here, we identify a novel essential regulator of Drosophila thoracic flight muscle development, the Hox TF Antennapedia (Antp). Correcting a long standing misconception that flight muscle development occurs without the input of Hox TFs, we show that Antp intervenes at several stages of adult flight muscle development, from the establishment of the progenitor pool in the embryo to myoblast differentiation in the early pupa. Furthermore, the precisely regulated clearance of Hox at the pupal stage in the developing indirect flight muscle fibers is required to allow for stretch-activated fibrillar muscle fate diversification that sets these flight muscles apart from all other adult tubular muscle types. For the role of Antp in 0h APF pupal myoblasts, that will fuse and differentiate into adult flight muscle, Mef2-Gal4;UAS-GFPnls flies were crossed to either UAS-Y RNAi or UAS-Antp RNAi. Myoblasts were dissociated from 0h APF dissected wing discs, FACS sorted, RNAi prepared and sequenced. All samples represent each genotype repeated with three independent biological replicates (triplicates)