Figure 3

Different BMP and Nodal Signaling Ranges Arise from Differential Signaling Activation Kinetics

(A) Single clones expressing mouse BMP4 (mBMP4) induce the formation of a secondary axis in zebrafish embryos (arrowhead). Scale bar, 150 μm.

(B) Mathematical modeling shows that a difference in signaling activation kinetics could explain how a single gradient of mBMP4 induces pSmad5 and pSmad2 at different ranges.

(C) Wild-type zebrafish embryos with clones expressing mBMP4 30 min and 180 min post-transplantation immunostained with anti-pSmad5 (red) and anti-pSmad2 (green) antibodies. The clones were labeled with cascade blue-dextran (blue). Scale bars, 150 μm.

(D) Higher magnification of images shown in (C) with separated fluorescent channels. Scale bar, 150 μm.

(E) MZsqt;cyc embryos with clones expressing mBMP4 30 min and 180 min post-transplantation immunostained with anti-pSmad5 (red) and anti-pSmad2 (green) antibodies. The clones were labeled with cascade blue-dextran (blue). Scale bars, 150 μm.

(F) Higher magnification of images shown in (E) with separated fluorescent channels. Scale bar, 150 μm.

(G) Zebrafish Bmp2b/7-sfGFP and Squint-mVenus clones in morphotrap-expressing wild-type embryos 30 min post-transplantation. Scale bar, 150 μm.

(H) Double clones with fluorescently tagged or untagged zebrafish Nodal and BMP and with narrow or wide spacing were generated in morphotrap-expressing embryos. The frequency of the different structures induced by the clones was assessed 24 h post-transplantation.