(A) Immunohistochemical and in situ hybridization analyses of E12.5 Chx10orJ/+ and Chx10orJ/orJ littermates. The ventral spinal cords are shown. Sox14/Lhx3-expressing V2aINs are reduced in Chx10orJ/orJ spinal cords. While the number of Hb9+/Isl1+ MNs did not significantly change, Hb9+/Isl1+ MNs emigrate abnormally from the spinal cord into the motor axonal track outside of the spinal cord (arrows) in Chx10orJ/orJ mice. The expression of the cholinergic gene VAChT is also increased in the ventral spinal cords of Chx10orJ/orJ mice.
(B) Quantification of the number of V2aINs and MNs in E12.5 mice. The change of the number of V2aINs and MNs in Chx10orJ/orJ spinal cords is relative to their control littermates. The error bars represent the standard error of the mean. **, p<0.01; *, p<0.05; ns, non-significant; n≥5 embryos.