Fig. 3. Pax6 overexpression affects late cortical progenitor proliferation. (A-C) Coronal sections at (A) rostral, (B) central and (C) caudal levels of the cortex (left hemisphere shown) of an E12.5 wild-type embryo labeled with anti-BrdU (brown). Cell counts were made in 100 µm-wide sampling boxes (red boxes). (D,E) Examples of anti-BrdU labelling (brown) of coronal sections of the cortex of (D) a wild-type and (E) a PAX77 embryo at E12.5. (F) The proportion of AP cells in S-phase along the cortex of PAX77 embryos at E12.5 is not different from that of wild type. (G,H) Example of anti-BrdU labeling (brown) of coronal sections of the cortex of (G) a wild-type and (H) a PAX77 embryo at E15.5. (I) The proportion of AP cells in S-phase in the rostral and central cortex of PAX77 embryos at E15.5 is significantly decreased compared with wild type. (J,K) Example of anti-phosphorylated histone H3 labeling (brown) of coronal sections of the cortex of (J) a wild-type and (K) a PAX77 embryo at E15.5. (L) The density of AP cells in M-phase in the rostral and central cortex of PAX77 embryos at E15.5 is significantly decreased compared with wild type. All sections shown are counterstained with cresyl violet. MZ, marginal zone; VZ, ventricular zone; SVZ, subventricular zone. Scale bars: 50 µm in A-E, 70 µm in G,H,J,K.