FIGURE 4.

Beat-GFP suppresses innervation defects caused by overexpression of Side-Cherry. (A-C) Confocal images (tile scans) showing three abdominal hemisegments of larval fillet preparations stained with phalloidin (magenta) and anti-Discs large (Dlg) antibodies (green, originally recorded at 647 nm). Arrows indicate neuromuscular junctions (NMJs) at muscles 1/9, 2/10 and 8. Arrowheads mark the respective non-innervated fibers. (A) In w ¹¹¹⁸ control larvae, each muscle fiber (magenta) is innervated by at least one NMJ (green). (B) Overexpression of Side-Cherry in all muscles prevented formation of NMJs on dorsal muscles and, to a lesser extent, also on lateral muscles. (C) Dorsal and lateral NMJs re-form when Side function is blocked by simultaneous co-expression of Beat-GFP (arrows). Arrowheads indicate fibers that still lack NMJs. Scale bar: 200 μm. (A'–C') Quantitative analysis of muscles innervated by the ISN. Muscles 1, 2, 3, 4, 9, 10, 11, 18, 19 and 20 were evaluated for the presence or absence of Dlg-positive NMJs. Innervation percentages for a given muscle fiber were coded in grey shades. Black indicates 90–100% innervation of a given muscle fiber by its NMJ, the lightest grey indicates 0–10% innervation. Re-appearance of dark colors in (C') shows the improvement of innervation. (D) Color-code indicating percentage of innervation of a given muscle. Black 100%, every muscle fiber evaluated is innervated; White 0%, none of the muscles is innervated; n = 44 or more hemisegments for each muscle.