Fig. 4. Ectopic mouse MyoD expression in the neural tube switches off the endogenous neuronal differentiation program, 4 days after electroporation. Transverse sections from embryos electroporated with mouse MyoD, 4 days after electroporation were hybridised with the DIG-labelled antisense probe for mouse MyoD (A,B) to show the location of ectopic mouse MyoD. Adjacent sections hybridised with the neural markers, SCG10 (C,D) and BEN (E,F) and then incubated with the MF20 antibody (D-F) show that neuronal markers are downregulated in the regions where are visualised muscle differentiation, assayed by MF20 labelling. (B,D,F) Higher magnifications of the ventral regions of the neural tube, framed in A,C,E, respectively. One day after electroporation, transverse adjacent sections (G,H), hybridised with the DIG-labelled antisense probe for mouse MyoD (G) and SCG10 (H) show a downregulation of SCG10 expression on the electroporated (right) side compared with the control (left) side (H).