Evidence that FoxH1 and Cyt1 act in the same pathway. (A–C) Similar effect of cyt1 and foxh1 mRNA over-expression on eye development. Wild type embryos were injected with 150 pg of foxh1 mRNA, 200 pg of cyt1 mRNA or 300 pg of gfp mRNA and scored after one day of development. No obvious defects arose from gfp mRNA injection. A reduced eye phenotype, as in B′, arose in 16% (N = 31) of embryos injected with cyt1 mRNA and a similar reduced eye phenotype, as in C′, arose in 23% (N = 39) of embryos injected with foxh1 mRNA. Primes (′) indicate the front view for the same embryos. (D–F) Cyt1 MO injection partially phenocopies the FoxH1 morphant phenotype. Wild type embryos were injected with 8 ng of the indicated MOs, embryos were dechorionated and soft-mounted in agar/agarose, then simultaneously time lapse documented. Primes (′) indicate different time points for the same embryos. Injection of both Cyt1 MO and FoxH1 MO caused epiboly delays at earlier stages (i.e. shield, 80% epiboly and 3-somite stages), and embryonic death later, at the 16-somite stage. However, the Cyt1 morphant phenotype was less severe than the FoxH1 morphant phenotype. (G–L) Reduced neurectodermal marker expression in both Cyt1 morphants and FoxH1 morphants. Wild type embryos were injected with 8 ng of the indicated MOs, then fixed at the bud stage (10 hpf) for whole mount in situ hybridization. G–I, lateral views, dorsal to the right. J–L, dorsal views, animal pole to the top. Signature markers were reduced in Cyt1 morphants, but reductions were more pronounced in FoxH1 morphants.
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