Fig. 4.

Alkaline phosphatase (ALP) activity and the formation of mineralized nodules in the Fam20c^f/f primary and immortalized cell lines. A: After 1 week’s culture in the mineralization-inducing medium, in situ cytochemsitry of ALP activity showed positive staining in the primary dental papilla mesenchymal cells, primary calvarial osteoblasts, and the induced immortalized dental papilla mesenchymal and osteoblast cell lines. B: After 2 weeks of mineralization-inducing culture, condensed mineralized nodules were also detected by Alizarin Red S staining in the primary dental papilla mesenchymal cells, primary calvarial osteoblasts, the induced immortalized dental papilla mesenchymal and osteoblast cell lines.