Fig. S3 ace mutants have normal axial and epithalamic Nodal signalling; subtle asymmetries in fgf8 expression are Nodal-dependent
(A,B) Axial expression of the Nodal ligand encoding southpaw (spaw) gene is unaffected in ace mutant embryos: 97.5 % of ace embryos (B) had left-sided spaw expression compared to 99 % of wild-type embryos (A) at 20 ss.
(C,D) Epithalamic expression of the Nodal ligand encoding pitx2 gene is largely unaffected in ace mutant embryos: 90 % of ace embryos (B) had left-sided pitx2 expression compared to 100 % of wild-type embryos (A) at 26 ss.
(E,F) fgf8 is expressed in the absence of Nodal signalling at 28 hpf, as shown by expression in the late zygotic (LZ) oep mutant (F). However, subtle asymmetries in fgf8 expression levels seen in wild-type embryos (E, black arrowhead) are lost in embryos lacking epithalamic Nodal signals (F, black arrowheads).