Fig. 3
Fig. 3
Fgf signaling depends on Twist1 and regulates a subset of ectomesenchyme gene expression.
(A,B) In situs at 18 hpf show that expression of the Fgf target gene pea3 is reduced in the arches (numbered) of twist1a/1b-MO embryos (n = 8/8) compared to un-injected controls (n = 0/12). (C–L) sox10:Gal4VP16; UAS:dnFgfr1a embryos show ectopic arch expression of sox10 at 18 hpf (n = 8/8) versus controls (n = 0/8), reduction of dlx2a at 24 hpf (n = 3/3) versus controls (n = 0/3), but no change in fli1a at 24 hpf (n = 0/7) versus controls (n = 0/5). twist1a expression was unchanged at 24 hpf in dnFgfr1a embryos (n = 10) compared to controls (n = 7), as was twist1b expression in dnFgfr1a embryos (n = 8) compared to controls (n = 8). Black arrows indicate the second arch, white arrowheads the ear, and red arrowheads the vasculature. Scale bar = 50 μm.