A specific requirement for PDGF-C in palate formation and PDGFR-α signaling

PDGF-C is a member of the platelet-derived growth factor (PDGF) family, which signals through PDGF receptor (PDGFR) αα and αβ dimers. Here we show that Pdgfc^-/- mice die in the perinatal period owing to feeding and respiratory difficulties associated with a complete cleft of the secondary palate. This phenotype was less severe than that of Pdgfra ^-/- embryos. Pdgfc^-/- Pdgfa^-/- embryos developed a cleft face, subepidermal blistering, deficiency of renal cortex mesenchyme, spina bifida and skeletal and vascular defects. Complete loss of function of both ligands, therefore, phenocopied the loss of PDGFR-α function, suggesting that both PDGF-A and PDGF-C signal through PDGFR-α to regulate the development of craniofacial structures, the neural tube and mesodermal organs. Our results also show that PDGF-C signaling is a new pathway in palatogenesis, different from, and independent of, those previously implicated.