Fig. 5

Left–right asymmetry phenotype in grb^tm304 mutant embryos. (A–C) Ventral views of wild-type and grb^tm304 embryos at 72 hpf. Wild-type animals display normal heart looping phenotype (A). Heart looping is frequently absent (B) or inverted (C) in grb^tm304 mutant embryos. (D–F) In situ hybridization staining for a heart marker, cmlc2, at 3 dpf. Normal heart orientation in the wild type is shown in (D). The absence of obvious heart looping (E) or reverse looping (F) in mutant embryos. (G–I) The expression of lefty1 in embryos collected from crosses between grb^tm304/+ heterozygotes. The lefty1 transcript is expressed on the left side of neural tube in the majority of embryos (G). The lefty1 expression domain extends to both sides (H) or is absent (I) in some embryos. (J, K, and L) The expression of lefty2 in embryos collected from crosses between grb^tm304/+ heterozygotes. (J) The normal expression of lefty2 transcript on the left side of the lateral plate mesoderm. The lefty2 expression domain shifts to the right side (K) or is absent (L) in some embryos. A, atrium; V, ventricle. In all panels anterior is up. Arrowhead indicates the midline.