CNS-derived Hsp70 promotes motoneuron survival. A, Transverse section of the lumbar spinal cord at E8 labeled with Hoechst 33342 (blue), GFP (green), or an antibody against mouse Hsp70 (red) after in ovo electroporation at E3 with a plasmid expressing mouse Hsp70-IRES2-GFP under the control of the chicken β-actin/CMV promoter. B, Enlarged images of the lateral motor column; white dots encircle the LMC. Scale bar, 50 μm.