Fig. 3. Overexpression of c-Gcm1 promotes premature neuronal differentiation. Electroporation with control or c-Gcm1 expression vectors in truncal neural tube (A-B',E-J') or telencephalon (C,D) of E1.5 embryos. Immunolabeling with ßIII-tubulin (Tuj1 in A-E), HuC/D (G-H') and Lim1/2 (I-J') neuronal markers were performed 24 hours after electroporation. (A-H') Electroporation of control vector (green in A,C,G,I) does not modify the expression pattern of ßIII-tubulin (red in A,A',C) or HuC/D (red in G,G'), whereas c-Gcm1 overexpression (green in B,D,E,H,J) leads to ectopic differentiation of Tuj1-positive (red in B,B',D; blue in E, arrows) and HuC/D-positive (red in H,H') neurons in the neuroepithelium. Inserts in B and H are high magnifications of c-Gcm1-overexpressing cells that coexpress ßIII-tubulin and HuC/D, respectively. (E) ßIII-tubulin (blue) and Pax7 (red) coimmunolabeling shows that c-Gcm1-overexpressing cells coexpress ßIII-tubulin but not Pax7 (arrows). (I-J') Compared with control (I,I'), c-Gcm1 overexpression induces the generation of Lim1/2-positive neurons within the ventricular zone (J,J'). (F) Percentage of transfected cells expressing ßIII-tubulin (Tuj1) and Lim1/2 after electroporation of control or c-Gcm1 expression vectors. Differences between the percentage of c-Gcm1 transfected cells expressing neuronal markers versus controls are statistically significant (asterisks, P<0.001). Scale bars: 40µm in A-D,G-J'; 10µm in insert in B,H; 20µm in E.