Combinatorial signaling establishes distinct Fox expression domains. (A) In situ hybridization at 36?hpf shows expression of Fox genes (green) relative to dlx2a+ CNCs (red) of the first two arches. (B) Expression of foxc1a, foxd2 and foxf1 (green) relative to dlx2a+ CNCs (red) upon misexpression of Shha, Bmp4 or Fgf3. Embryos doubly transgenic for hsp70l:Gal4 and UAS:shha, UAS:bmp4 or UAS:fgf3 were subjected to heat shock induction from 20 to 24?hpf and then fixed at 36?hpf for analysis. (C) Expression of foxc1a, foxd2 and foxf1 (green) relative to dlx2a+ CNCs (red) in edn1 or jag1b mutants versus sibling controls. Numbers denote proportions of embryos with displayed patterns. Scale bars: 25??m. (D) Summary of positive and negative inputs on Fox expression in the first two arches.
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