Spaw, Dand5 and Lefty1 are required for left-right asymmetry. (A) Expression patterns of spaw, vg1/gdf3, dand5 and lefty1 in wild-type zebrafish embryos. LPM, lateral plate mesoderm; N, notochord; KV, Kupffer's vesicle. (B) Spaw induces itself and its inhibitor Lefty1. Spaw is also inhibited by Dand5. (C) Wild-type (WT), dand5, lefty1 (lft1), spaw, dand5;lft1, dand5;spaw and lft1;spaw embryos at 28 h post-fertilization (hpf). See Table S1 for information about the mutant alleles. (D) Quantification of heart jogging at 28 hpf in wild-type and mutant embryos. (E) Quantification of heart looping at 2 days post-fertilization (dpf) in wild-type and mutant embryos, detected by expression of myl7/cmlc2 by in situ hybridization. D-loop, dextral loop; S-loop, sinistral loop. A large proportion of hearts failed to loop correctly in either direction, forming no loop or a very mild loop. We designated these embryos as ‘mild/no loop’. (F) Expression of lefty1, spaw and lefty2 (lft2) at the 10-somite stage (10SS) and 21SS in wild-type and mutant embryos. Each image is representative of three to five independent experiments (embryo number is in bottom right corner of each panel). Scale bar: 150 µm.
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