Effect of GST-N-DSP on MC3T3-E1 osteoblast differentiation. MC3T3-E1 cells were treated with GST or GST-N-DSP, and further cultured for up to 10 days. The expression of osteogenic/dentinogenesis markers was analyzed by real-time PCR. The normalized values are shown as the mean±S.D. and statistically analyzed (n=3). *; p<0.05, **; p<0.001. Runx2; Runt-related transcription factor 2, Osx; Osterix, Atf4; Activating transcription factor 4; Col1a2; Collagen type 1 alpha 2 chain, Dspp; Dentin sialophosphoprotein, Dmp1; Dentin matrix protein 1, Gapdh; Glyceraldehyde-3-phosphate dehydrogenase.