Figure 2—figure supplement 1.

Figure 2—figure supplement 1.

To test whether Cyclops and Squint spread over a long range in the absence of Oep, we generated MZoep;cyc and MZoep;sqt double mutants and performed sensor cell assays. (A) Squint signals over a long range in the absence of Oep. Representative sensor cell assays for MZoep;cyc^+/+ (left), MZoep;cyc^+/- (middle) and MZoep;cyc^-/- (right) are presented. Mvg1 sensor cells are marked with α-GFP immunostaining (yellow), and sensor cell boundaries are outlined in white in the α-pSmad2 images (magenta). YSL boundaries are marked with a white dashed curve in all images. (B) Quantification of Nodal signaling in sensor (red) and host cells (green) in MZoep;cyc double mutant embryos. Host cells lack oep, and so represent immunostaining background. A pSmad2 gradient from a wild-type embryo was quantified and plotted in each panel for comparison (blue). Gradients for MZoep;cyc^+/+ (left), MZoep;cyc^+/- (middle) and MZoep;cyc^-/- (right) were derived from 2, 2 and 3 replicate embryos, respectively. Sliding window averages are plotted as solid curves. (C) Cyclops signals over a long range in the absence of Oep. Representative sensor cell assays for MZoep;sqt^+/+ (left), MZoep;sqt^+/- (middle) and MZoep;sqt^-/- (right) are presented. Mvg1 sensor cells are marked with α-GFP immunostaining (yellow), and sensor cell boundaries are outlined in white in the α-pSmad2 images (magenta). (D) Quantification of Nodal signaling in sensor (red) and host cells (green) in MZoep;sqt double mutant embryos. Host cells lack oep, and so represent immunostaining background. Gradients for MZoep;sqt^+/+ (left), MZoep;sqt^+/- (middle) and MZoep;sqt^-/- (right) were derived from 4, 3, and 5 replicate embryos, respectively. Sliding window averages are plotted as solid curves.