Fig. 9

The expression of PSAT1 was regulated by transcription factor ATF4. A, B The mRNA levels of ATF4 and PSAT1 in PDLSCs after osteogenic induction for 3 and 7 days. C The protein levels of ATF4 and PSAT1 in PDLSCs after osteogenic induction for 3 and 7 days. D, E The mRNA and protein levels of ATF4 and PSAT1 in PDLSCs after ATF4 was overexpressed. F, G The mRNA and protein levels of ATF4 and PSAT1 in PDLSCs after ATF4 was interfered. H, I The mRNA and protein levels of ATF4 and PSAT1 in PDLSCs with ATF4 overexpressed after osteogenic induction for 7 days. J Jasper database and PROMO database were used to predict a combination of ATF4 protein and PSAT1 promoter. K The predicted binding sites in promoter region of PSAT1 that could bind to transcription factor ATF4. L GTRD database was used to analyze the combination peak of ATF4 and PSAT1 promoter regions. M ChIP experiment verified that ATF4 could bind to the predicted region of PSAT1. NC: PDLSCs that were cultured in the complete culture medium. OI: PDLSCs that were cultured in the osteogenic medium. OEATF4: PDLSCs that were transfected with the pcDNA3.1 vector containing full-length ATF4. pcDNA3.1: PDLSCs that were transfected with empty pcDNA3.1 vector. siATF4: PDLSCs that were transfected with siRNA-targeted ATF4. siNC: PDLSCs that were transfected with siRNA-targeted none. *p < 0.05; **p < 0.01