Fig. 5. Asymmetric distribution of canonical Wnt/ß-catenin signaling pathway components in the node. All images are posterior views of cross sections, the left side of the embryo is facing left. (A) Merge of confocal microscopy images of E7.75 wild-type embryo labeled with anti-ß-catenin antibody (B), rhodamine phalloidin (C) and DAPI (D). (E-H) Expression of the Wnt/ß-catenin target gene Nkd1 in four-somite stage wild-type (E,F) and Wnt3a^-/- (G,H) embryos. Arrows indicate sites of asymmetric expression in the wild-type node. Boxed regions in E and G are represented as high-power views of the nodes in F and H, respectively. All assessments of Nkd1 distribution were performed on whole embryos by whole-mount in situ hybridization (not shown), and subsequently sectioned for confirmation and clarity.