(A) Horizontal section of wild type flies at the pharate adult stage. The muscles, stained for accumlation of F-actin, are large and contain numerous nuclei. (B) Horizontal sections of sing knockdown flies at the pharate adult stage show there is a significant failure of muscle formation in the knockdowns. (A’) Higher magnification of control sample at the pharate adult stage showed robust muscle formation with numerous nuclei per muscle fiber. (B’) Higher magnification in sing knockdown animals. The residual muscles that do form are the DLMs, which are smaller than their control counterparts, and only have sparse nuclei. In all panels Phalloidin (red) was used to visualize F-actin, and DAPI (blue) was used to visualize nuclei. Lamin (green) was detected to outline nuclei in A’ and B’ panels. DLM, Dorsal longitudinal muscle; DVM, Dorsoventral muscle; TDT, tergal depressor of the trochanter (jump muscle). Scale bar, 20 µm for A, B; 10 µm for A’, B’.