Confocal analysis of brp isoform mutants NMJs. (A and D) Two boutons of NMJs on muscles 6/7 from third instar larvae with the indicated genotypes labeled with the indicated ABs. (B) Quantification of BRP^N-Term AB staining intensity measured over the whole NMJ (HRP mask). Control: 100.0 ± 9.1; brp^Δ170: 80.4 ± 19.0, P = 0.8785 versus control; brp^Δ190: 0.0 ± 10.7, P = 0.0002 versus control, P = 0.0047 versus brp^Δ170; n = 8 NMJs in four larvae/genotype. (C) Quantification of BRP^C-Term AB staining intensity measured over the whole NMJ (HRP mask). Control: 100.0 ± 5.0; brp^Δ170: 58.2 ± 2.5, P < 0.0001 versus control; brp^Δ190: 51.8 ± 2.4, P < 0.0001 versus control, P = 0.0667 versus brp^Δ170; n = 27 NMJs in nine larvae/genotype. (E) Quantification of the number of DRBP^C-Term dots measured over the whole NMJ (HRP mask). Control: 100.0 ± 5.5; brp^Δ170: 93.5 ± 4.7, P = 0.4781 versus control; brp^Δ190: 89.9 ± 5.4, P = 0.1800 versus control and P = 0.4889 versus brp^Δ170; n = 27 NMJs in nine larvae/genotype. (F) Quantification of the number of GluRIID dots measured over the whole NMJ (HRP mask). Control: 100.0 ± 8.0; brp^Δ170: 84.9 ± 6.4, P = 0.1455 versus control; brp^Δ190: 89.3 ± 7.7, P = 0.3266 versus control, P = 0.6925 versus brp^Δ170; n = 18 NMJs in six larvae/genotype. All quantifications were normalized to control. Error bars represent SEMs. **, P ≤ 0.01; ***, P ≤ 0.001; n.s., P > 0.05, Mann–Whitney U test. n is as indicated in the bars.