Figure 5

Appearance of intramedullary sensory neuron-like cells in Six1/4^EGFP/EGFPmice precedes disorganization of the dorsal root entry zone. (A) Number of enhanced GFP (EGFP)- and ISL1/2-double-positive cells in 10 μm sections of embryonic day (E) 10.5 to 12 Six1/4^EGFP/EGFP thoracolumbar spinal cord. (B) EGR2-positive cells (magenta) at the dorsal root entry zone (DREZ) (arrowheads) and at the motor exit point (MEP) (arrows) do not overlap with EGFP (green) and show comparable distribution in E11.5 embryos of Six1/4^+/EGFP and Six1/4^EGFP/EGFP. ISL1/2 (magenta) marks dorsal root ganglion neurons. (C) Number of EGR2-positive cells in 10 μm sections of E10.5 to E11.5 at the DREZ and MEP of Six1/4^+/EGFP and Six1/4^EGFP/EGFP. (D) Total length of laminin gaps in 50-μm length of basal lamina covering the primordium of the dorsal funiculus. In all measurements, at least five sections from three embryos were used per genotype. Data are mean ± standard error of the mean. *p <0.005. Dashed lines demarcate the position of ectoderm and spinal cord (sc). Scale bar: 50 μm.