Supplemental Figure S1
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Fig. S1. Inhibition of Fgf signaling blocks neuralization by Chordin and prevents NC induction by Fgf8 and Wnt8. (A) In animal explants neuralized by Chordin (C), Fgf8 (F)-mediated induction of Wnt8 is blocked by the MAPK inhibitor (+U0126). (B,C) The MAPK inhibitor (+U0126) blocks neuralization by Chordin (C). In animal explants co-injected with Chordin and Fgf8a (C+F), or Chordin and Wnt8 (C+W), and cultured in the presence of the MAPK inhibitor (+U0126), the NC marker Snail2 is severely downregulated. These results indicate that neuralization by Chordin requires active Fgf signaling, and suggest that the dramatic reduction of Snail2 expression in Fgf8a- and Wnt8-treated explants is likely to be secondary to the inability of Chordin to neuralize the ectoderm in the absence of an active MAPK pathway. Explants were cultured for 5 (A) or 10 (B,C) hours. Values (n=3) are presented as mean±s.e.m.; *P<0.05, as indicated. For keratin, all values are compared to uninjected animal explants (U).
