(A) Gene expression analysis of Alp, Sp7, Ibsp and Bglap in Jnk1-/- and Jnk2-/- COBs after 7 days of osteoblast differentiation conditions (n=4). (B) ALP activity (left) and representative ALP staining (right) in Jnk1-/- and Jnk2-/- osteoblasts at day 7 of osteogenic induction (n=3). (C and D) Representative non-soluble ECM pellets and Von Kossa staining in differentiated Jnk1-/- and Jnk2-/- COBs at day 14 of osteogenic induction. (E and F) Immunoblotting of phospho-JUN in Jnk1-/- COBs at day 7 of osteogenic induction. (G) and immunohistochemistry for phospho-JUN in Jnk1-/- femurs (bone collar and cortex) in 6-week-old mice. (I) Gene expression analysis of Fosl1, Fosl2, Vegfa and Igf2 in Jnk1-/- COBs at day 7 of osteogenic induction (n=4). (H) CateGOrizer summarizes biological process functions from Gene Ontology (GO) based on DEGs between WT and Jnk1-/- COBs. The fraction of the piechart presents the proportion of genes involving with given function. (J) GO enrichment analysis of DEGs between WT and Jnk1-/- COBs indicated ten significantly overrepresented functions using DAVID. Each bar is colored and labeled according to p-value of enrichment analysis. (K) Longitudinal sections of femurs from WT and Jnk1-/- mice; OSX and Jnk1/2osx mice at 6-weeks of age were subjected to immunofluorescence staining for endomucin (red) and DAPI (blue). Scale bars, 300μm. Error bars, mean ± s.d. *P < 0.05.