Artificial, uniform Nodal inhibition rescues morphology at 4 dpf in lefty1-/-;lefty2-/- mutants.
(A) Wild type and lft1-/-;lft2-/- mutant embryos were exposed to 0, 1.25, 2.5, 3.75, 5, or 6.25 μM SB-505124 (Nodal inhibitor drug) starting at the 8 cell stage, sphere stage, or shield stage. Drug was removed at 24 hr post-fertilization. Percent of embryos with normal gross morphology at 4 days post-fertilization (dpf) is plotted. (B) Unexposed wild type embryo at 4 dpf. (C) A ~ 3 month old female lft1-/-;lft2-/- mutant exposed to 2.5 μM SB-505124 from the 8 cell stage to 24 hpf. Drug-rescued mutants are fertile. Spotted pigmentation is common in incrossed TLAB strains. (D–R’) Embryos exposed to SB-505124 from the 8 cell stage to 24 hpf (D–H’), sphere stage to 24 hpf (I–M’), and shield stage to 24 hpf (N–R’) at 4 dpf. Number of embryos with same phenotype as image out of total is indicated in bottom right of images. Occasionally, embryos that appeared normal at 1 dpf had evident defects at 4 dpf, and embryos that appeared abnormal at 1 dpf recovered by 4 dpf.