Figure 1.

Expression of ta and fscn1a in the Margin Is Regulated by Fgf Signaling

(A) Whole-mount immunofluorescence for phosphorylated Erk (P-Erk) in DMSO- and SB-505124-treated 50% epiboly embryos. DAPI labels the nuclei.

(B) Western blot for P-Erk in pooled 50% epiboly embryos treated with indicated compounds. Actin is a loading control.

(C) Western blot for P-Erk and total Erk in pooled 40%–50% embryos after control treatment or FgfR inhibition. Actin is a loading control.

(D) WISH for ta, fscn1a, lft1, and lft2 in control embryos, embryos incubated with SU-5402, or embryos injected with mRNA encoding dnFgfR, at 40%–50% epiboly. For fscn1a, animal views are shown. Red brackets outline the width of the WT ta expression domain.

(E) qPCR for indicated Nodal target genes on pooled 50% epiboly embryos treated with DMSO (D), SB-505124 (SB), or SU-5402 (SU). Depicted is the mean expression ± SD normalized to eef1a1l1 levels and compared with levels in DMSO-treated cells (^∗p < 0.01, t test; n = 3). ns, not significant.

(F) Western blot for P-Smad2 and Smad2 in pooled 40%–50% embryos treated with the indicated compounds. Mcm6 is a loading control.

(G) Sections of DMSO- and SU-5402-treated 40%–50% epiboly embryos stained for ta.

(H) Quantification of the number of cell tiers from the margin that express ta. Depicted is the mean ± SD (^∗p < 0.01, Mann-Whitney U test; n > 50).

See also Figure S1.