Figure 4

(A) Lateral view of the zebrafish trunk showing a nkx2.2a⁺/foxd3⁺ MEP glial cell (outlined arrowhead) delaminate from the lateral floor plate and exit the spinal cord in a control embryo and nkx2.2a⁺/foxd3⁺ MEP glia unable to exit the spinal cord (white arrowhead) in an embryo treated with 100 µM GM6001 from 36 to 48 hpf. (B) Percentage of MEP glia in the spinal cord, absent, or present along motor nerves at 55 hpf in DMSO control (n = 68 nerves from six embryos) and GM6001- treated embryos (n = 68 nerves from eight embryos). (C) Percentage of MEP glia in the spinal cord, absent, or present along motor nerves at 72 hpf in DMSO control (n = 70 nerves from seven larvae) and GM6001-treated larvae (n = 70 nerves from seven larvae). (D) Transverse sections of foxd3:mcherry;nkx2.2a:megfp spinal cords at 72 hpf showing nkx2.2a⁺/foxd3⁺ MEP glia in the PNS (outlined arrowheads) in DMSO control and nkx2.2a⁺/foxd3⁺ MEP glia in the lateral floor plate (arrowhead) in GM6001-treated larvae. Yellow dashed lines outline the edge of the spinal cord. (E) In situ hybridizations showing mmp17b in the spinal cord of foxd3^+/- and foxd3^-/- siblings and adamts3 expression in the spinal cord of foxd3^+/- and foxd3^-/- siblings and foxd3 mRNA injected embryos at 48 hpf. Scale bar, (A, D, E) 10 µm.