Fig. 4

RB spinal sensory neuron axons maintain minimal ensheathment in a target axon-deficient environment. a Lateral view images of the posterior spinal cord show ensheathment of RB sensory axons in control (non-injured siblings) and ablated larvae (24 hpi, 96 hpf). Note that oligodendrocytes had not yet formed sheaths within this spinal cord segment at the time of ablation, and therefore all sheaths observed in the ablated group were formed in a reticulospinal axon-devoid environment. Brackets indicate individual sheaths wrapping RB axons. Scale bar = 5 μm. b Quantification of RB axon ensheathment. Scatter plot points represent the total number of sheaths wrapping isl1[ss]:DsRed⁺ RB axons in the posterior spinal cord of individual larvae (posterior to somite 2). n (larvae) = 29 (control), 25 (ablated). c Quantification of average sheath lengths. Scatter plot points represent the average length of all sheaths wrapping RB axons within an individual larva. n (larvae, total sheath #) = 20, 80 (control) and 16, 60 (ablated). For b-c, error bars represent mean ± SEM and p-values report Mann-Whitney test