Fig. 1

Ebf1 and Ebf2 are expressed in axial muscle-innervating motor neurons. a Schematic of the spinal cord showing different columns of MNs (color-coded) at distinct regions along the rostro-caudal axis (brachial and thoracic). A cross-section of each region is provided below. b RNA ISH analysis for mouse Ebf1-Ebf4 at e13.5 of WT spinal cords. c Schematic summarizing the expression of Ebf1 (HMC) and Ebf2 (MMC) based on data from panel B. On the right, axonal projections are schematized of HMC and MMC neurons to hypaxial and epaxial muscles, respectively. d Antibody staining for the LMC marker (Foxp1, green signal) combined with fluorescent RNA ISH for Ebf3 (red signal) revealed almost no co-localization in WT e13.5 spinal cord. N = 3. e-f: Double immunostaining for Lhx3 (MMC marker in red) and bGal (Ebf2 reporter in green) shows that ~ 40% of MMC neurons express Ebf2. Quantification (f) provided as the ratio of MNs that are double positive for Lhx3 and bGal over the total number of Lhx3 positive MNs. For this analysis, Ebf2 ^LacZ/+ embryos were used at e12.5. N = 5