Fig. 5

CoPA spinal interneuron axons maintain a constant ensheathment rate in a target axon-deficient environment.a Lateral view images of the posterior spinal cord show ensheathment of CoPA axons in control (non-injured siblings) and ablated larvae. The indicated time points (24 and 36 hpi) were acquired at 72 and 84 hpf, respectively, and acquired in a constant spinal cord segment (somites 16–17). Note that ablation was performed prior to the initiation of oligodendrocyte differentiation and axon wrapping (48 hpf), and therefore all sheaths observed and counted formed after ablation of descending reticulospinal axons. Brackets indicate individual sheaths wrapping CoPA axons. Scale bar = 2 μm. b-d Quantification of CoPA axon ensheathment (b-c) and overall sheath lengths (d). Scatter plot points represent measurements of individual axons (b-c) or total number of sheaths wrapping tbx16⁺ CoPA axons (d) and error bars represent the mean ± SEM. n (larvae, total sheath #) = 28, 94 (control 24 hpi); 16, 53 (ablated 24 hpi); 23, 99 (control 36 hpi); 20, 92 (ablated 36 hpi). Reported p-values were generated using a two-tailed, unpaired t-test to compare groups at matched time points