Morphological phenotypes at the NMJ of Dscam2 mutants. (A–D) Representative images of HRP immunoreactivity (magenta) labeling nerve terminal membrane and anti-Syn (green) labeling synaptic boutons in control (A), Dscam2^null (B), Dscam2A (C), and Dscam2B (D). Scale bar, 20 µm. Inset scale bar, 5 µm. (E and E’) Quantification of the absolute number of boutons per NMJ (E) and muscle 6 cross-sectional area (E’). (F–J’) Representative images of HRP immunoreactivity (magenta, F–I), which was used to quantify bouton size in Ib (J) and Is (J’) axon terminals. Scale bar, 5 µm. (K–O’) Representative images of anti-brp immunoreactivity (green, K–N) and quantification of the number of puncta/bouton in Ib (O) and Is (O’) boutons. Scale bar, 5 µm. (P–T’) Representative images of GluRIIA immunoreactivity (red, P–S) and quantification of immunofluorescence (IF) intensity normalized to control at Ib (T) and Is (T’) boutons. Scale bar, 5 µm. Data shown as mean ± SEM; n indicated in graph; and one-way ANOVA, groups compared with Tukey’s post-test. *, P < 0.05; ***, P < 0.001; ****, P < 0.0001 for all panels. IF, immunofluorescence.