Figure Figure 7.

Proposed model of bone formation governed by Osx in adult bone. With the lack of Osx during the animal's growth, differentiation of pre‐osteoblasts into mature osteoblasts is delayed and immature osteoblasts accumulate, accompanied by the increased expression of early marker genes for osteoblast differentiation. Although bones are formed, BFR and bone mass are significantly reduced. However, Osx‐inactivated adult mice have no obvious defect in osteoclast differentiation because the relative ratio of RANKL/OPG is not remarkably changed, even though the expression of RANKL and OPG is highly increased. Thus, Osx is a positive regulator in adult bone formation.