NODAL signaling moves inward independently of BMP and WNT.

Images of samples immunostained for SMAD2/3 after 44 h of BMP treatment. The time between BMP4 and inhibitor (LDN or IWP2) addition is indicated above the image. No chemical inhibitor was added in the No-LDN sample. Quantification represents average nuclear intensities of indicated markers normalized to DAPI as a function of radial position. Error bars represent standard error. N ≥ 10. Scale bar = 100 μm. Underlying data can be found in S6 Data. BMP, Bone Morphogenic Protein; LDN, LDN193189.