Fig. 6. valentino (val) RNA is sufficient to recover some posterior hindbrain identity in vhnf1 mutants. (A-F) Injection of val+lacZ RNA or lacZ alone. Embryos are 12-somite stage. (A) Injection of val RNA into wild-type embryos has no effect on endogenous krox20 expression. (B) Injection of val RNA into vhnf1 embryos recovers r5 krox20 expression (arrow) within the injected cells in 7/8 mutant embryos. (C) Injection of lacZ RNA alone is not sufficient to recover krox20 expression. (D) Injection of val RNA into wild-type embryos at the 12-somite stage does not affect hoxb3 expression (arrow). (E) Injection of val RNA into vhnf1 mutant embryos recovers some hoxb3 expression in 5/14 embryos. (F) Injection of lacZ RNA alone does not rescue hoxb3 expression.