Figure 2

Nodal and BMP Form Similar Protein Gradients but Have Different Signaling Ranges during Secondary Axis Formation

(A) Bmp2b/7-sfGFP as well as Squint-mVenus and Bmp2b/7-sfGFP double clones in wild-type or maternal-zygotic swirl mutant (MZswr) embryos at 1 day post-transplantation, with untransplanted embryos for comparison. The arrowheads point to ectopic secondary axes. Scale bar, 150 μm.

(B) Bmp2b/7-sfGFP clones compared to uninjected mock clones 30 min and 180 min post-transplantation in wild-type or MZswr embryos. Embryos were immunostained with anti-pSmad5 (red) and anti-GFP (blue) antibodies. Mock sources were labeled with cascade blue-dextran (blue). Scale bar, 150 μm.

(C) pSmad5 distributions in embryos with single Bmp2b/7-sfGFP clones in MZswr embryos at 30 min (n = 9), 60 min (n = 8), 120 min (n = 10), and 180 min (n = 9) post-transplantation. Shaded regions indicate 95% confidence intervals around the mean (lines). Scale bar, 150 μm.

(D) Squint-mVenus as well as Squint-mVenus and Bmp2b/7-sfGFP double clones in wild-type or maternal-zygotic squint and cyclops double mutant (MZsqt;cyc) embryos 1 day post-transplantation, with untransplanted embryos for comparison. The arrowheads point to ectopic structures or secondary axes. Scale bar, 150 μm.

(E) Squint-mVenus clones compared to uninjected mock clones 30 min and 180 min post-transplantation in wild-type or MZsqt;cyc embryos. Embryos were immunostained with anti-pSmad2 (green) and anti-GFP (blue) antibodies. Mock sources were labeled with cascade blue-dextran (blue). Scale bar, 150 μm.

(F) pSmad2 distributions in embryos with single Squint-mVenus clones in wild-type embryos at 30, 60, 120, and 180 min post-transplantation (n = 11 each). Shaded regions indicate 95% confidence intervals around the mean (lines).

(G) BMP protein gradients in wild-type embryos with single Bmp2b/7-sfGFP clones at 30, 60, 120, and 180 min post-transplantation. The same embryos were imaged throughout the time course (n = 14). Fluorescence intensity was converted to concentration based on a calibration curve using recombinant sfGFP imaged with the same microscope settings. Shaded regions indicate 95% confidence intervals around the mean (lines).

(H) Nodal protein gradients in wild-type embryos with single Squint-mVenus clones at 30, 60, 120, and 180 min post-transplantation. The same embryos were imaged throughout the time course (n = 12). Fluorescence intensity was converted to concentration based on a calibration curve using recombinant mVenus imaged with the same microscope settings. Shaded regions indicate 95% confidence intervals around the mean (lines).

See also Figures S2–S4.