Figure 4.

Loss of specific neuronal populations in Lmx1b^CND mutants. All panels represent cervical spinal cord sections caudal to level C5 at E18.5. A, B, Detection of Hoxb8 mRNA in E18.5 spinal cord at cervical level C7 shows expression in dorsal horn of Lmx1b^CTL and Lmx1b^CND mice. C–E, Immunodetection of Lmx1b shows a ∼40% reduction in the number of Lmx1b-positive cells in Lmx1b^CND at cervical level C7 (323 ± 21 Lmx1b⁺ cells in Lmx1b^CTL vs 183 ± 43 Lmx1b⁺ cells in Lmx1b^CND mice, p = 0.007, n = 3). F, G, The number of NK1R-expressing cells is reduced in lamina I of Lmx1b^CND. The lamina I and lamina II+III domains are also reduced in Lmx1b^CND. H–J, The number of cells expressing reelin mRNA is significantly reduced in lamina I-III in Lmx1b^CND (122 ± 24 reelin⁺ cells in Lmx1b^CTL lamina I-III vs 28 ± 11 reelin⁺ cells in Lmx1b^CND lamina I-III, p = 0.003, n = 3). K–M, Sst-expressing cells also show a reduction in number in the dorsal horn of Lmx1b^CND mice (77 ± 10 Sst⁺ cells/section in Lmx1b^CTL vs 31.6 ± 5 Sst⁺ cells/section in Lmx1b^CND, p = 0.002, n = 3). N–P, Lim1 immunodetection shows the same number of expressing cells in lamina I-III in Lmx1b^CND and in Lmx1b^CTL (264 ± 21 Lim1⁺ cells/section in Lmx1b^CTL lamina I-III vs 269 ± 80 cells/section in the Lmx1b^CND lamina I-III, p = 0.92, n = 3). Error bars indicate ±SD. Scale bar, 50 μm. **p < 0.01; ns, Not significant.