Fig. 7. Gbx2 rescue Otx2 but not Fgf8 expression. Embryos were injected in one blastomere at the two cells stage with 0.5 ng of HD-GR (A,C), or with 0.5ng of HD-GR and 1 ng of Gbx2 (B,D). The inducible constructs were induced around stage 12.5 and the injected side was detected by the Myc immunostaining. (A) Caudal expansion of the Otx2 midbrain domain (black lines) in embryos injected with HD-GR mRNA. (B) A nearly normal Otx2 expression is restored with the co-expression of Gbx2 and HD-GR (black lines). (C) Injection of HD-GR produced a complete inhibition of Gbx2. (D) The co-injection of HD-GR and Gbx2 did not rescue the expression of Fgf8, even though it produced a nearly normal Otx2 expression. Arrowheads show the injected sides and point the effects described above. Each experiment was carried out at least twice with a minimum of 54 embryos. The percentage of effect (or rescue) for each experiment was 
70%.
