Fig. 1.

Expression levels of macrophage-stimulating protein (MSP) and the RON receptor during osteoblast differentiation. (A, B) Expression profiles of MSP and its receptor RON mRNA in bone, liver, and testis, bone marrow stromal cells (BMSC), calvarial pre-osteoblasts (primary OB) from mice. Reverse transcription-polymerase chain reaction (RT-PCR) (A) and quantitative RT-PCR (qRT-PCR) (B) analyses were performed. Results are expressed with fold changes compared to the levels of the genes in BMSCs. (C, D) Changes in RON mRNA expression during osteoblast differentiation. Primary calvarial pre-osteoblasts were cultured with osteogenic medium, containing ascorbic acid (AA, 50 μg/mL) and β-glycerophosphate (β-GP, 5 mM) (C), or bone morphogenetic protein 2 (BMP2; 200 ng/mL) (D). At the indicated time points, total RNA was harvested, and then RT-PCR (left panel) and qRT-PCR (right 3 panels) were performed. Results of the qRT-PCR analysis are expressed as fold change over the control group. *P<0.05. (E) RON protein expression was evaluated using Western blotting analysis with an anti-RON antibody in AA-and β-GP-treated cells. β-actin expression is used as a loading control. Ocn, osteocalcin.