Fig. 5

Fgf signaling was necessary for FoxD5 expression during early somitogenesis. Using WISH to detect the expression of FoxD5 and myod in wild-type (WT) embryos, fgf3 mutants, fgf8 mutants, and embryos treated with different materials, as indicated. Embryos were incubated for 6 h in SU5402, starting at 6 hpf; heterozygous strain of fish derived from transgenic line Tg(hsp70l:dnfgfr1-EGFP)pd1 were crossed with WT individuals, and their progeny were heat shocked at 10 hpf for 1 h, followed by WISH analysis at 12 hpf. In both sets of experiments, the expression of FoxD5 in the anterior PSM and adaxial cells was greatly reduced (B, C). In fgf8 (D) and fgf3 mutants (E), the expression of FoxD5 was slightly reduced. However, in fgf3-/fgf8-double-MO-injected embryos, FoxD5 transcripts were almost lost (F). In WT, myod was detected in the somites and adaxial cells (G). While myod could still be detected in the somites and the adaxial cells in fgf3-/fgf8-double-MO-injected embryos (H), it could only be detected in the adaxial cells in embryos treated with SU5402 (I).