Fig. 3

TGF-β1 regulates SOCS7 expression at the transcriptional level via EGR1. A. Schematic diagram showing the locations of the predicted overlapping binding sites for EGR1 (in red) and SP1 (in red and underline) (E/S sites) on the SOCS7 promoter. E/S sites were predicted using JASPAR and Animal Transcription Factor databases. B. HaCaT cells were transfected with luciferase constructs under control of a SOCS7 promoter encompassing either the wild-type sequence (pGL4-E/S) or a mutant with the putative binding S/E sites deleted (pGL4-ΔE/S), or with pGL4 and a renilla control plasmid for 24 h. Then, cells were treated with TGF-β1 (10 ng/ml) for 24 h and the luciferase activity was measured. C. HaCaT cells were transfected with EGR1 siRNA (siR-EGR1) or SP1 siRNA (siR-SP1) for 24 h, stimulated with or without TGF-β1 (10 ng/ml) for 24 h, then the luciferase activity was measured. D. HaCaT cells were treated with or without TGF-β1 (10 ng/ml) for 24 h. Representative ChIP assay of TGF-β1-mediated EGR1 and SP1 binding to the SOCS7 promoter is shown. Data are given as mean ± standard deviation (SD) of three independent experiments. *P < 0.05; **P < 0.01; ***P < 0.001