BMP4-coated beads induce, and NOG-coated beads inhibit, epibranchial formation. Lateral views, anterior to the left. In situ hybridization for phox2b mRNA to label epibranchials at 48 hpf. (A) Wild-type control embryo. (B-F) Embryos that received Affi-Gel Blue beads soaked in either PBS (B), BMP4 (10 µg/ml, C; 1 µg/ml, D) or NOG protein (500 pg/ml, E; 300 pg/ml, F). Arrows in C and D indicate ectopic phox2b+ cells adjacent to the bead; arrows in E and F denote missing ganglia adjacent to the NOG-coated bead. Asterisks indicate beads. gVII, facial; gIX, glossopharyngeal; gX, vagal; ot, otic vesicle. Scale bar: 50 μm.
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