The interferon-inducible protein p205 acts as an activator in osteoblast differentiation of mouse BMSCs.

p205, an interferon-inducible protein, is induced in the course of osteogenesis in mouse bone marrow stromal cells (BMSCs). Knocking down p205 markedly impairs whereas overexpressing p205 enhances the osteoblast differentiation of BMSCs, as revealed by the altered expression of osteogenic genes, the change of ALP activity and the ARS-stained mineral nodules. The positive role of p205 in BMSC osteogenesis is probably due, at least in part, to the association of it with Id proteins. Further investigation indicated that p205 may disturb the formation of Runx2/Ids complex and free more Runx2 to induce the differentiation process. Taken together, our findings demonstrated for the first time that p205 functions as an activator in osteoblast differentiation.