Graded BMP signaling within intestinal crypt architecture directs self-organization of the Wnt-secreting stem cell niche
Cell Stem CellShivdasani et al. assign niche functions to specific mesenchymal cell types near stem cells at the base of intestinal crypts. They identify PDGFRAlo fibroblasts as a substantial source of requisite Wnt ligands and show that BMP signaling from crypt