Fig. 6.

Fig. 6.

Endoderm-specific Bmp signaling responses are lost in bmp4^−/−;smad5^−/− embryos but not in ethanol-treated zebrafish embryos. (A-D′) Whole-mount, confocal images of bmp4;smad5;sox17:EGFP;BRE:mKO2 wild-type or bmp4^−/−;smad5^−/− embryos at 36 hpf that had been ethanol treated (+EtOH) (C-D′) or not (A-B′). Ectoderms were fluorescence labeled for GFP (false-colored magenta) and for active Bmp signaling with mKO2 (false-colored green). Views are lateral, with anterior to the left. Boxed areas within A-D are shown magnified (40×) in A′-D′, respectively. Scale bar: 100 μm. Arrows in A′ and C′ indicate overlap of Bmp signaling response and sox17-labeled endoderm in wild-type embryos. Compared with wild-type embryos (A,A′,C,C′), the endoderm-specific Bmp signaling response is lost in bmp4^−/−;smad5^−/− embryos (B,B′,D,D′). Ethanol exposure does not alter the Bmp response (C-D′). Embryos per group: wild type (n=5); bmp4^−/−;smad5^−/− (n=4); wild type + EtOH, n=4; bmp4^−/−;smad5^−/− (n=8).