Figure 3.

Synergistic effects in Notch1^−/− Notch4^−/− double mutant embryos. (A) Two Notch1^−/− Notch4^−/− double homozygous mutant embryos and littermate control isolated at E9.5. (B) Severely affected Notch1^−/− Notch4^−/− double homozygous mutant embryo. The double homozygous mutant embryos in both A and B have not completed embryonic turning and have open neural tubes. (C) A typical Notch1^−/− embryo and control littermate at E9.5. The Notch1^−/− mutant embryo has completed turning and has a closed neural tube.