(A) Representative light microscopy images of spinal cord sections of Fus+/+, FusΔNLS/+, FusΔNLS/ΔNLS and Fus-/- mice at birth stained with cresyl violet (Nissl, A1, A3 A5, A7), or anti-choline acetyl transferase (ChAT, A2, A4 A6, A8).(B-C) Quantification of ChAT+ motor neurons (B) and Nissl+ motor neurons (defined as Nissl positive cells with a soma area >80µm2) (C) per spinal cordventral horn in FusΔNLS/ΔNLS mice. For Nissl+ N=8 Fus+/+, N=5 FusΔNLS/+, N=7 FusΔNLS/ΔNLS and for ChAT+ N=7 per genotype, (**) p<0.01 vs Fus+/+, (##) p<0.01 vs Fus∆NLS/+ ; One way ANOVA followed by Tukey post hoc test.(D-E) Quantification of ChAT+ (D) and Nissl+ (E) motor neurons per spinal cordventral horn in Fus-/- mice. N=6 per genotype, no significant differences were found, by Student's unpaired t-test. 