Karlsson L, Lindahl P, Heath J, Betsholtz C. Abnormal gastrointestinal development in PDGF-A and PDGFR-(alpha) deficient mice implicates a novel mesenchymal structure with putative instructive properties in villus morphogenesis. Development. 2000;127:3457-66 pubmed
..The role of PDGF-A seems to be to secure renewal of PDGFR-(alpha) positive cells when they are consumed in the initial rounds of cluster formation. ..