Fig. 8

Disruption of the ventricular zone apical surface in Akirin2 knockout embryos. a, b High magnification images of the control (a) and Akirin2 knockout (b) ventricular zone at E11 stained for N-cadherin and connexin-43. In controls, these proteins are very prominent at apical cell-cell junctions at the ventricular surface, and connexin-43 is also observed at gap junctions through which the cell bodies of progenitors are coupled (a). Both proteins are patchy and severely reduced in Akirin2 knockouts, and are absent at sites where cells are “spilling” into the lateral ventricle (b). Red arrowheads show chromatin condensation in pyknotic DAPI-stained nuclei observed in the Akirin2 knockout cortex (b). Akirin2 knockout embryos at E11 also display “rosette-like” circular cell clusters within the VZ that contain some Sox2-positive cells but do not stain for Pax6 (white arrows; c). The cells that spill into the lateral ventricle in Akirin2 knockout cortex appear to be Sox2+ but Pax6– (d, white arrowheads). The dashed line indicates the apical ventricular surface. LV, lateral ventricle; VS, apical ventricular surface. Scale bar: 50 μm