Fig. 8. Runx2 phosphorylation regulates osteoblastic differentiation in primary bone marrow stromal cells (BMSCs). BMSCs were transduced with Runx2-WT, Runx2-125Gly, or Runx2-125Glu retrovirus and cultured in osteogenic media with (+) and without (–) 10 nM DEX. (A) ALP activity was examined by a biochemical assay at 7 days post-transduction [mean ± s.e.m., n =3; ANOVA: P<1E-4; ^*different from unmodified cell control, ^**different from unmodified and DEX-only controls, different from Runx2-DEX, ^£different from 125Glu-DEX only (P< 0.05)]. (B) Mineralized matrix deposition was assessed by von Kossa staining for phosphate-positive regions and image analysis at 14 days post-transduction. Image represents data from two separate experiments in triplicate. Bar, 2 cm.