Deletion of her6 facilitates M-cell axon regeneration and has no effect on growth and development in zebrafish larvae. a Generation of her6−/− and Tg (Tol-056); her6−/− zebrafish. b, c Homozygote knockout of her6 promoted M-cell axon regeneration (control: 378.8 ± 21.57 μm, n = 20 fish; her6+/−: 476.6 ± 26.42 μm, n = 19 fish, p = 0.0066; her6−/−: 691.4 ± 36.86 μm, n = 20 fish; p < 0.0001). White asterisk: ablation point; arrowhead, axon regeneration terminal. scale bar, 50 μm. Assessed by unpaired t-test. d, e Total lengths of M-cell axons from the cloaca to the end were not notably different among WT, heterozygous and homozygote larvae (control:1406 ± 23.34 μm, n = 8 fish; her6+/−: 1458 ± 36.60 μm, n = 8 fish; her6−/−: 1441 ± 20.15 μm, n = 8 fish, p = 0.4140). White asterisk: ablation point; arrowhead, axon regeneration terminal. scale bar, 50 μm. p = 0.4140, assessed by one-way ANOVA, ns, not significant. f, g Trajectory diagrams and motion distance statistics of free swimming within 1 h of her6−/−(control: 645.8 ± 28.62 cm, n = 24 fish; her6+/−: 668.5 ± 28.90 cm, n = 24 fish; her6−/−: 654.2 ± 33.29 cm, n = 24 fish). p = 0.8674. Assessed by one-way ANOVA. ns, not significant. h, i Representative images of larvae from the wildtype, her6+/− and her6−/− at 6 dpf (scale bar, 500 μm), and measured total body length from 4 to 6 dpf (4 dpf: control: 3.807 ± 0.0193 mm, n = 15 fish; her6+/−: 3.820 ± 0.0238 mm, n = 15 fish; her6−/−: 3.831 ± 0.01201 mm, n = 15 fish, p = 0.6737; 5 dpf: control: 3.938 ± 0.0168 mm, n = 15 fish; her6+/−: 3.958 ± 0.0174 mm, n = 15 fish; her6−/−: 3.970 ± 0.0194 mm, n = 15 fish, p = 0.4588; 6 dpf: control: 4.066 ± 0.0185 mm, n = 15 fish; her6+/−: 4.034 ± 0.0153 mm, n = 15 fish; her6−/−: 4.098 ± 0.0251 mm, n = 15 fish, p = 0.0907). Assessed by two-way ANOVA, ns, not significant
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