Fig. 7

FoxD5, which was mediated by Fgf signaling, controlled mespa and mespb expressions during somitogenesis. WISH was used to detect mespa and mespb in the wild-type embryos (WT), mutants and embryos injected with different materials as indicated at 12 hpf. Two stripes of mespa expression in the PSM were observable in WT embryos (A), but they were slightly reduced in the fgf3 mutants (C). The mespa signal was lost in S0 in fgf8 mutants (E) and greatly reduced in the heat-shocked embryos derived from transgenic line Tg(hsp70l:dnfgfr1-EGFP)pd1 (G) and in the fgf3-/fgf8-double-MO-injected embryos (I). Three stripes of mespb transcripts were detected in the PSM of WT embryos. Although they were slightly reduced in the fgf3 (D) and fgf8 mutants (F), these three stripes of mespb were greatly lost in the heat-shocked embryos derived from the transgenic line Tg(hsp70l:dnfgfr1-EGFP)pd1 (H) and in the fgf3-/fgf8-double-MO-injected embryos (J). Co-injection of fgf3-/fgf8-double-MO with FoxD5 mRNA enabled embryos to rescue expression of mespa and mespb, but neither the striped pattern of mespa nor that of mespb was restored (K-N). The expression of mespa in the FoxC1a morphants appeared to be unaffected (O), but the expression of mespb in FoxC1a morphants was greatly reduced (P).