Fig. 3

Developmental Regulation of Territory Reinnervation Strategy

(A-C) Growth potential of uninjured axons is developmentally regulated.

(A and B) Confocal projections. Dorsal view of zebrafish head is shown with anterior up. Olive indicates denervated half of head. Scale bars represent 50 μm. Ablation of the left trigeminal ganglion at 30 hpf (A) or 78 hpf (B) is shown.

(C) Quantification of axon growth rate in unablated (olive) versus ablated (red) animals. Values are the average growth in µm/hr of individual branch tips. Error bars represent ±SEM. See Table S3 and Movies S5 and S6.

(D-G) Examples of control axons (wild-type cells transplanted into wild-type host) axotomized at 30 hpf (D) or 78 hpf (F) compared to isolated regenerating axons (wild-type cells transplanted into ngn-1 morphant host) axotomized at 30 hpf (E) or 78 hpf (G). Tracing overlays as in Figure 2 are shown. Arrowhead is site of axotomy, olive marks denervated territory, and scale bars represent 50 μm.

(H) Quantification of the area reinnervated by the injured axon, calculated as in Figure 2J. Error bars represent ±SEM. See Table S1 and Movies S7-S10.

(I) Model of the developmental regulation of skin reinnervation by the terminal arbors of peripheral sensory axons. Black bar indicates site of axotomy. Injured axons are red; uninjured axons are green.