Objective: To investigate the transcriptional activation of
p53 gene promoter by low dosage
Arsenic Trioxide (As2o3). Methods:
Polymerase chain reaction (PCR) technique was employed to amplify the coding sequence of p53 promoter from HepG2 genomic DNA, and the product was subcloned into pCAT3-Basic by Kpn I and Xho I, named pCAT3-p53p. pCAT3-p53p was transfected into the hepatoblastoma cell line HepG2, then cotransfected with As2O3 by FuGENE 6 transfection reagents. The HepG2 cells transfected with pCAT3-Basic was used as negative control. The activity of promoter region fused to the CAT gene in HepG2 cells transfected was detected by a ELISA kit after 48 hours, which reflected the transregu-lating function of As2O3 to p53p gene promoter. Results: The report vector pCAT3- p53p had been constructed and had been confirmed by restriction enzyme digestion and sequencing. The expression of CAT in HepG2 cells co-transfected with pCAT3- p53p and As2O3 was respectively 0. 076, 0. 186, 0. 149, 0. 119, the CAT activity of pCAT3- p53p was 11.2 times as higher as that of pCAT3-Basic,while lower to pCAT3-promoter,the results also showed a descent tendency of CAT activity as concentration of As2O3 shift. Conclusions: As2O3 can transregulate the transcriptional activation of p53 promoter rage in low dosage, and so can down-regulate the expression of p53 gene.