Fig. 2. FoxH1 regulates Xnr3 gene expression in a specific fashion. (A) Embryos derived from oligo injected and control uninjected oocytes were frozen at 2-hour intervals during the blastula and gastrula stages, and assayed by real-time RT-PCR for the relative expression of organizer genes Xnr3, siamois, chordin and goosecoid. Expression levels were normalized to ODC. (B) 15 pg of Foxh1 mRNA injected into the vegetal area of wild-type embryos causes increased activation of ARE-luciferase reporter compared to control levels, while higher doses inhibit the activation of ARE-luciferase reporter. (C) The reintroduction of 15 or 30 pg of Foxh1 mRNA into FoxH1-depleted oocytes before maturation rescues the expression of Xnr3 and chordin mRNA at the early gastrula stage. (D) The reintroduction of 30 pg of Foxh1 mRNA into FoxH1-depleted oocytes before maturation rescues the headless phenotype.