(D) Representative confocal images of stage 17 embryonic heads highlighting expression of Dfd (purple), Myosin in muscles (blue) and FasII in axonal projections (green) in control (elav>RFP) animals and after RNA interference with three different homeodomain TF genes, Dfd, hth and mirr, which are all co-expressed in MN2a (see Fig 2E). A zoom on the projection (FasII staining) of MN2a to the MHE and MHD muscle of an early stage 17 Drosophila embryo are shown. Asterisks highlight the location of MN2a, which is in all cases identified by the FasII expressing axonal projection emerging from a Dfd expressing MN, which normally innervates the Dfd expressing MHE muscle (as shown in the elav>RFP control). The panel on the right side represents a schematic drawing of the confocal image shown on the left side, summarizing the innervation of the anterior muscles (LR, MHE, MHD) by projections emerging from MN2a (magenta) in control and perturbation conditions. 