Fig. 6

FGF signalling is necessary and sufficient for activating shroom3 expression in the pLLP. (A-N′) Lateral views of zebrafish embryos stained by ISH with a shroom3 probe. Treatment of embryos with 10 μM of SU5402 (C-D2), or overexpression of dn-fgfr1 (H-J) totally inhibits shroom3 expression in the pLLP (compare C-D2 with A-B′, and H-J with E-G). Overexpression of fgf3 after heat-shock of Tg(hsp70l:fgf3-Myc)^zf115 embryos leads to an increase and expansion of shroom3 expression (compare M-N′ with K-L′). (O) Quantification of the length of the ′shroom3-free′ zone in the leading region in heat-shocked Tg(hsp70l:fgf3-Myc)^zf115 (red) and non-transgenic siblings (blue). Statistical analyses were performed using the t-test. Error bars represent s.e.m. Scale bars: 200 μm in A,C,E,H,K,M; 20 μm in B,B′,D,D′,F,G,I,J,L,L′,N,N′.