Fig. 3

Loss of Gdf3 leads to expansion of Bmp signaling.

(A) Knockdown of nodal related 1 (ndr1) and nodal related 2 (ndr2) in wild-type (WT) embryos causes complete loss of head and trunk mesendoderm and defects in tail patterning. (B) ndr1:ndr2 knockdown in MZgdf3 embryos causes loss of residual tail patterning, producing embryos that more closely resemble those completely lacking Nodal signaling (A). (C-E) Overexpression of 1 pg or 10 pg ndr1 led to increased expression of the Nodal target gene goosecoid (gsc) in WT embryos. (F-H) Overexpression of 10 pg ndr1, but not 1 pg, produced widespread expression of gsc in MZgdf3 mutants. (I) Immunostaining of phosphorylated Smad1/5/8 (green) counterstained with DAPI (blue). Ventral pSmad levels were increased in MZgdf3 mutants. (J) Plotting the normalized pSmad1/5/8 intensity over position on the ventral-dorsal axis confirms that MZgdf3 embryos (n = 14) have increased BMP signaling in the ventral region compared to WT (n = 13). (K-M) RNA in situ hybridization of eve1 showed expansion of expression in the ventral region of MZgdf3 embryos (K) compared to WT (L). (M) Quantitative comparison of WT (n = 14) and MZgdf3 (n = 12) embryos confirmed expansion of the ventral eve1 expression domain in MZgdf3 embryos. (N-Q) RNA in situ hybridization of chordin (chd) revealed its expression is reduced in MZgdf3 embryos. All views are animal unless otherwise indicated. In M, p-value obtained by Student’s t-test (two-sided, homoscedastic). Error bars in J and M, standard error of the mean. Matlab code and data are available as Figure 3—source code 1, 2, and 3 and Figure 3—source data 1 and 2.