Differential regulatory roles of MAZ and Sp1 on transactivation through binding to the 34-nt sequence motif of the edn promoter. (A) Cotransfections and luciferase assays were performed with HepG2 cells in the presence of pcDNA3, pcDNA3/MAZ or pcDNA3/MAZΔF34. (B) Similar to (A), but cotransfection was performed with pcDNA3 or pcDNA3/Sp1. (C) Cells were transfected with 40 pmol/well Sp1/RNAi1, Sp1/RNAi2, or RNAi control. Forty-eight hours later, cells were harvested and protein lysates were separated by 8% SDS-PAGE and transferred to a PVDF membrane that was probed for Sp1 or actin. (D) Cotransfections and luciferase assays using wt and Δ (-81/-48) edn promoter constructs were carried out with HepG2 cells in the presence of control RNAi, Sp1/RNAi1 or Sp1/RNAi2. The difference between the two groups is statistically.