Localization of CAR in embryos on E13.5. Color codes are the same as those in Fig. 1. Each boxed area in a–g is enlarged in a'–g' (CAR) and a''–g'' (SOX2) as merged images with DAPI. Open arrowheads indicate a SOX2-single positive cell in the ependymal zone of the spinal cord. VC; ventricular cavity, ME; mesencephalon, PE; prosencephalon, RE; rhombencephalon, DE; diencephalon, CE; cerebellum, SC; spinal cord. Scale bars 500 μm (a–g), or 50 μm (a''–g'').