Figure 4

Evaluation of neuromuscular defect in mutant larvae. (a) The number of viable embryos after successful mating of WT fish (n = 10) compared to homozygous desma^kg97 (n = 10) (P = 0.6842, Mann–Whitney U) or homozygous desmb^kg156 (n = 8) (P = 0.9654, Mann–Whitney U) fish. (b) Comparison of hatching rate between homozygous mutants and WT 24, 48 and 72 hpf embryos At 72 hpf, no significant difference in the hatching rate was found between mutants and WT (desma^kg97/kg97 vs. WT, P = 0.9902; desmb^kg156/kg156 vs WT, P = 0.3186, repeated measures two-way ANOVA, Bonferroni post hoc test) (c) Body length of 96 hpf WT (N = 18) and homozygous desma^kg97 (N = 25) or homozygous desmb^kg156 (N = 16) mutant embryos (P = 0.2036 for WT vs. desma^kg97/kg97; P = 0.1893 for WT vs. desmb^kg156/kg156, Mann–Whitney U). (d) Cumulative mortality rate from 1 to 5 dpf homozygous desma^kg97 mutants (N = 1247) compared to WT (N = 2460) (P = 0.1287, repeated measures two-way ANOVA, Bonferroni post hoc test) and homozygous desmb^kg156 mutants (N = 2615) compared to WT (P = 0.6239, repeated measures two-way ANOVA, Bonferroni post hoc test). (e) Optical sections of the mid-trunk region of WT and homozygous mutants 96 hpf embryos (N = 8) stained with rhodamine phalloidin (F-actin) with insets showing striations (asterisks indicate occasional wavy fibres in both WT and mutants). Scale bar: 50 µm. (f–h) Touch-evoked escape time (ms) of 48 hpf embryos. Motility experiments were performed blind on siblings from (f) desma^kg97/+, (g) desmb^kg156/+ or (h) desma^kg97/+;desmb^kg156/kg156 in-crosses followed by post hoc genotyping. (f) Heterozygous desma^kg97 embryos (N = 23) were compared to WT (N = 9) (P = 0.122, Mann–Whitney U) and desma^kg97/kg97 (N = 15) compared to WT (P = 0.5529, Mann–Whitney U). (g) Heterozygous desmb^kg156 embryos (N = 6) were compared to WT (N = 38) (P = 0.3968, Mann–Whitney U) and desmb^kg156/kg156 (N = 6) compared to WT (P = 0.6131, Mann–Whitney U). (h) Homozygous double mutants (N = 8) were compared to desma^+/+;desmb^kg156/kg156 (n = 15) (P = 0.3165, Mann–Whitney U) and desma^kg97/+;desmb^kg156/kg156 embryos (n = 34) compared to desma^+/+;desmb^kg156/kg156 (P = 0.2334, Mann–Whitney U).