Identification of transcription factors involved in PDGF-induced OPN expression in VSMCs.

<p>(A) Cells were transiently transfected with various promoter constructs or an empty luciferase vector (pGL3) for 24 hrs, and then stimulated with PDGF (10 ng/ml) for 4 hrs. Relative luciferase activities were presented as the means ± SEMs of 12 independent experiments. **<i>P</i><0.01 vs. non-treated control. (B) Nucleotide sequence of the -538 ~ -234 promoter region of the OPN gene. The transcription factor binding sites were identified using TFSearch software. The sequences of potential binding sites for AP-1 and C/EBPβ in pLuc-OPN-538 were underlined. (C) The bindings of AP-1 and C/EBPβ in PDGF-treated VSMCs were assessed using a ChIP assay. IgG was used as negative control. The images are representative of 4 independent experiments. Quantitative results were expressed as the means ± SEMs of 4 independent experiments. *<i>P</i><0.05 and **<i>P</i><0.01 vs. value at 0 hr.