Fig. 1

fsta is downstream of Nodal signaling and required for LR asymmetry of zebrafish. (A) WISH of fsta in 10 hours post-fertilization (hpf) zebrafish embryos. (B) From left to right: expression of fsta in zebrafish embryos injected with ndr2 mRNA in one blastomere of the animal pole at the 128-cell stage, or ndr1, ndr2, ndr1 and ndr2 MO at the 1-cell stage, and in tdgf1 zygotic mutant or maternal-zygotic mutant zebrafish embryos. (A and B) Numbers in the bottom right of panels indicate the number of embryos with the phenotype shown out of the total number of embryos examined. At least 34 embryos were examined in each experiment. (C) Schematic diagram showing the positions of ATG (translation start site) and splicing MO of fsta; the guide RNA(gRNA) target site; the deletions of two fsta mutant lines generated using CRISPR/Cas9; and the predicted truncated Fsta (Δ5/Δ4) proteins (predicted domains taken from the Uniprot database). (D) The positions of heart and cardiac looping of WT and fstaΔ5/Δ5 embryos were analyzed using the cardiomyocyte marker myl7. The LR patterning of digestive organs including the liver, pancreas and intestines were analyzed using foxa3. (E) The epithalamic LR patterning of WT and fstaΔ5/Δ5 embryos was analyzed using the parapineal marker gfi1ab, pineal and parapineal marker otx5, and habenula markers kctd12.1, kctd12.2, and slc18a3b. Red triangles indicate asymmetric expression. Grey stacks indicate absence of expression. (D and E) Statistics are shown on the right of the representative photos, “n” indicates the numbers of examined embryos. At least 49 embryos were examined in each experiment. DV, dorsal view; LV, lateral view. (Scale bar, 200 μm.)