Fig 2.

Transcriptional effects of Sp1/Sp3 and GATA4 on ANF promoter. Luciferase assays were performed in HeLa cells to evaluate the effects of Sp1 or Sp3 with other transcriptional factors on the ANF-638 bp promoter-luciferase reporter construct (ANF-luc) in (A), (B), (D) and (E), or β-MHC promoter-luciferase reporter construct (β-MHC-luc) in (C). GST-Sp1 is a dominant-negative mutant of Sp1, which contains an intact DNA-binding region without an activation domain on the N-terminus and thus competitively blocks putative Sp1 DNA-binding sites. The total DNA amounts for transfection were kept constant using pcDNA3 plasmid DNA. The activities of luciferase reporters (ANF-luc or β-MHC-luc) were set as 1.0. pRL was used to normalize the transfection efficiency. Each bar represents mean ± S.D. from three independent experiments, each sample in triplicate. Cells transfected with pcDNA3 plasmid DNA were used as controls (Empty) (*P < 0.05).