Canonical Notch signalling through the DeltaD ligand controls left-right patterning. (A,B) Percentages of normal (Left, grey), reversed (Right, white), bilateral (black) and absent (stripes) expression of spaw (A) and pitx2 (B) in the lateral plate mesoderm when Notch signalling was challenged. Embryos were analysed between the 14- and 18-somite stages for spaw expression and between the 18- and 20-somite stages for pitx2. (C) Percentages of different domains of left-sided expression of spaw in the lateral plate mesoderm. (D,D2,F,F2,G) In aei-/- embryos, spaw may be expressed in an anterior domain only (D,D′), in an anterior with bilateral posterior domains (F,F′), and in anterior and posterior domains with competition on the right side (G). (E) A double spaw and lefty1 in situ hybridization showing the posterior gap (vertical line) of these two markers in an aei-/- embryo. (H-K) Expression of foxa3 in the gut in 50-53 hpf embryos (dorsal views). In wild-type embryos, the gut loops to the left (H). In aei–/– embryos, the gut may loop to the left (I), or to the right (J), or show no looping (K). (L) Percentages of normal (Left), reversed (Right) or no looping of the gut at 50-53 hpf. (M) Percentages of normal (Left), reversed (Right) or absent lefty2 in the lateral plate mesoderm at the 26-somite stage. (N) Percentages of normal (Left), reversed (Right) or no jogging (Centered) of the heart at 30-32 hpf.
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