Fig. 4

C/EBPβ is required for FOSB gene epigenetic transcription activation. a Schematic diagram shows FOSB gene promoter and putative C/EBPβ binding sites. TSS transcription start site. b MDA-MB-231 cells transfected with con-siRNA or siRNA against C/EBPβ were treated with or without 2 μM GSK343. The mRNA levels of FOSB in were determined by real-time PCR. The siRNA efficiency against C/EBPβ was determined by immunoblotting. c Overexpression of C/EBPβ activates FOSB promoter-driven luciferase activity. pGL4.15-Con or pGL4.15-FOSB plasmids were co-transfected with either empty vector (EV) or C/EBPβ in 293T cells. The luciferase activity was then measured. d The FOSB gene promoter contains two potential binding sites for C/EBPβ. Point mutations were highlighted with black cross, and the mutated residues were also highlighted in red. The transcriptional activity of wild-type or mutant FOSB promoters in 293T cells overexpressing C/EBPβ was then determined