Fig. 7. Fgf3 is sufficient to induce phox2a-positive epibranchial neurons. Zebrafish embryos were co-injected with HS-fgf3 and HS-gfp plasmids alone (top) or cas-MO (bottom) at the one-cell stage, heat shocked for 1 hour at 37°C beginning at 22 hpf and then assayed for phox2a expression (blue) and gfp expression (red) at 36 hpf. The majority of ectopic, phox2a-positive neurons (arrowheads) were immediately adjacent to the gfp-positive cells. Note significantly increased facial ganglion in cas morphant (bottom left) when compared with the contralateral control side. Anterior is at left. Scale bar: 50 µm. Abbreviations are as in Fig. 1.