Fig. 3. Molecular markers of CT and LMC motor neuron subtype identity. (A) Selective expression of Lim3 by medial MMC neurons at brachial levels of stage 29 spinal cord. (B) Selective expression of RALDH2 by LMC neurons at brachial levels of stage 29 spinal cord. RALDH2 is also expressed by roof-plate cells. (C) Co-expression of Isl2 and Lim1 by lateral LMC neurons at brachial levels of stage 29 spinal cord. (D) Pattern of Isl1/2 expression in motor neurons and dorsal interneurons at brachial levels of stage 29 spinal cord. (E,F) Absence of expression of BMP5 in motor neurons at brachial levels of the spinal cord. Arrows (F) indicate sites of BMP5 expression in roof-plate (left arrow) and mesenchymal cells surrounding the spinal cord (right arrow). (G) Expression of ephrinA5 in a subset of LMC motor neurons at brachial levels of the spinal cord. Arrow indicates ephrinA5 expression in a small group of cells just ventral to the dorsal root entry zone. (H) Motor neuron columnar organization at brachial levels of the spinal cord. (I,J) Selective expression of BMP5 in CT motor neurons at thoracic levels of the spinal cord. BMP5 is also expressed by roof-plate cells. (K) Expression of ephrinA5 in CT motor neurons at thoracic levels of the spinal cord. (L) Motor neuron columnar organization at thoracic levels of the spinal cord. (M) Widespread expression of MNR2 in dorsal spinal cord after in ovo electroporation of MNR2. Analysis performed at stage 29. (N) Co-expression of Lim3 by Isl1/2+ ectopic motor neurons after MNR2 electroporation. (O) Lack of expression of BMP5 in ectopic motor neurons at thoracic levels after MNR2 electroporation. (P) Lack of expression of RALDH2 in ectopic motor neurons at limb levels after MNR2 electroporation. Images are representative of over 30 electroporated embryos