Fig. 3

Neuronal cell soma ensheathment is distinct from axonal ensheathment. (a). Confocal z-projection images of a Tg(sox10:eos) zebrafish with a photoconverted neuron at 72 hpf. The top images were taken of an animal treated with DMSO. The bottom images were taken from an animal treated with SU6656. Red bracket denotes the width of the axon. Green bracket denotes the width of the ensheathing cells. (b, c). Intensity profiles of Tg(sox10:eos) unconverted (green) and Tg(sox10:eos) converted (red) transecting the axon from animals treated with DMSO (b) and SU6656 (c). Dashed red bracket denotes the width of the axon. Dashed green bracket denotes the width of the ensheathing cell. (d, e). Confocal three-dimensional images of a Tg(sox10:eos) DRG with a photoconverted neuron in DMSO and SU6656 treated animals. D denotes dorsal, M denotes medial, V denotes ventral, and L denotes lateral. (f). Ratio of the width of Tg(sox10:mcherry); Tg(ngn1:gfp) peaks taken from intensity profiles transecting the neuronal soma and axon (n = 10 DRG). (g) Area of the ensheathing cells in DMSO and SU6656 treated animals (n = 18 DMSO DRG, n = 11 SU6656 DRG). (h). Number of ensheathing cells per DRG at 72 hpf (n = 18 DMSO DRG, n = 11 SU6656 DRG). (i). Deconvolved confocal z-projections of a Tg(sox10:eos) DRG with a photoconverted neuron in a SU6656-treated animal. White arrow denotes the dorsal tip of an ensheathing cell on the DRG axon. (j-m). Graphs of the aspect ratio (j), roundness (k), circularity (l) and solidity (m) of the ensheathing cells before, during, and after axon initiation (n = 18 DMSO DRG, n = 11 SU6656 DRG). (g, h, j-m) use an unpaired Student’s t-test. (f) uses a paired Student’s t-test. Scale bar is 10 μm (a, d, e, i). All intensity measurements were taken from sum z-projections