Downregulation of p300 inhibited the odontoblast differentiation of the mDPCs. mDPCs were infected with either scramble or sip300. Then the cells were treated with odontoblastic induction medium. RNA and protein were obtained after 7 day’s induction. qRT-PCR (A) and immunoblots (B) were performed for p300, Dmp1, Dspp, Alp, and normalized to Actin. C, Normalized protein levels were shown in the chart. D, Mineralization was determined by alizarin red staining. All data were based on three independent experiments. mDPCs, mouse dental papilla mesenchymal cells; qRT-PCR, quantitative reverse transcriptase polymerase chain reaction. *P < .05, **P < .01, ***P < .001