Fig. 3. A nestin-Psen1 transgene rescues the cerebral hemorrhages but not the caudal defects in the Psen1^–/– embryo. (A-C) E18.5 wild-type (A), Psen1^–/– (B) embryos and an embryo with the nestin-Psen1 transgene on the Psen1^–/– background (C). The Psen1^–/– embryo has an abnormal tail region (arrow) and a cerebral hemorrhage (arrowhead). By contrast, the embryo with the nestin-Psen1 transgene on the Psen1^–/– background still exhibits the caudal defects (arrow) but no cerebral hemorrhages.