Fig. 5. Rescue of cerebral hemorrhages and cortical lamination defects in Psen1^–/– embryos with a nestin-Psen1 transgene. Cresyl Violet-stained coronal sections of E18.5 embryos from wild-type (A,F,K), Psen1^+/– (B,G,L), Psen1^–/– (C,H,M), nestin-Psen1 transgene on Psen1^–/– background (D,I,N) and nestin-Psen1 transgene on Psen1^+/+ background (E,J,O). (F-O) Higher power views through the lateral telencephalon. In the E18.5 embryos, the wild-type embryo shows a clear lamination pattern with a recognizable ventricular zone (VZ), intermediate zone (IZ), subplate (SP), cortical plate (CP) and marginal zone (MZ). The Psen1^–/– animal has multiple areas of hemorrhage (one indicated by arrow in M) and lacks distinct cortical layers. A cortical ectopia in the Psen1^–/– embryo is indicated by an arrowhead (M). By contrast, the embryo with the nestin-Psen1 transgene on the Psen1^–/– background, as well as the Psen1^+/– and the embryo with the nestin-Psen1 transgene on the Psen1^+/+ background, are normal in appearance. Scale bars: 500 µm in A-E; 100 µm in F-J; 50 µm in K-O.