Gcps of two altered anchoring centers in mutants exhibit the same coordinated changes as in WT. (a, c, e, g) Phalloidin staining (red) shows gcp morphology in sagittal sections of P0 WT (a, e) and En2 mutant mice (c, g). At P0, in the WT secondary fissure (a), gcps are more elongated (ci = 0.55) than gcps in the area of the prepyramidal fissure (e) (ci = 0.71). In contrast, in En2 mutants, the gcps in the secondary (c) and prepyramidal (g) fissures are similarly elongated. (b, d, f, h) Dotted white line outlines the EGL, based on the anti-Pax6 immunostaining of adjacent sections to depict the thickness of EGL. Asterisks indicate the base of the fissure. (i) Ci of gcps (gray is WT, white is mutant). Bar height indicates the mean value of each data set, and error bars indicate standard error. An asterisk indicates statistically significant differences between the base of the fissure and crown of the folia for each data set (p < 0.0009 for P0; p < 0.0002 for P1). (j) Anti-pH3 immunostaining at P0 reveals that there are more gcps in mitosis in the areas where the prepyramidal and secondary fissures will form than at the crown of folium VIII. Bar graphs depict quantification of the number of pH3 positive gcps in the prepyramidal fissure (light blue bars) and in the secondary fissure (dark blue bars) compared to the crown of the intervening folium (red bars). Bar height indicates the mean value of each data set, and error bars indicate standard error. An asterisk indicates statistically significant differences between the two regions (p < 0.004 for P0 for the prepyramidal fissure; p < 0.05 for P0 for the secondary fissure). Scale bar: 15 μm.