Fig. 1.

Spatiotemporal expression of sFRP-1 during ANE restriction. Aa–c sfrp-1 expression is first detected at the 32- to 60-cell stage and is present throughout the embryo until mid-blastula stage. Ad, Ae Between mesenchyme blastula stage and early gastrula, sfrp-1 is restricted to anterior and posterior blastomeres. Af–j foxq2 expression is first detected at 32- to 60-cells stage in the anterior blastomeres and is progressively downregulated from posterior ectoderm cells from the 60-cell to mesenchyme blastula stages as previously shown [21]. Ak–o Diagram showing a model for the areas of Wnt/β-catenin, Fzl5/8–JNK, and Fzl1/2/7–PKC signaling during ANE restriction consistent with the data from [20]. Each individual diagram corresponds to the developmental stages depicted in the panels directly above. B Functional protein domain organization for the CRD containing proteins including sea urchin sFRP3/4 (a) and secreted Frizzled-related protein 1 (b). Scale bar = 20 μm