Figure 3.

Reduction in synaptic growth and muscle innervation by Is motoneurons in Gbb mutants. A, Confocal images of third instar muscle M4 innervation by MN4-Ib (green, anti-HRP staining) and MNIs (magenta, MNIs GAL4>UAS-DsRed) in controls (top panels) or Gbb mutants (gbb¹/gbb², bottom panels). Muscles were labeled with phalloidin-conjugated Alexa Fluor 647 and are shown in blue. Dashed line indicates M4 muscle boundary and each neuron is labeled. Scale bar, 3 µm. B, Quantification of NMJ area for MN4-Ib or MNIs at third instar M4 defined by anti-HRP staining for controls and Gbb mutants. Each point represents the average NMJ area at M4 from segments A2–A4 for a single larva. C, Quantification of the percentage of M4 muscles innervated by MN4-Ib or MNIs at the third instar stage. Each point represents the average percentage of M4 innervation in segments A2–A4 from a single larva. Statistical significance was determined using Student's t test. Data are shown as the mean ± SEM. ***p < 0.001.