Figure 2

Effect of mithramycin on Sp1 binding with chromatin immunoprecipitation (ChIP) assays. Closed ovals indicate Sp1-binding sites. Open ovals indicate interferon-stimulated response element (ISRE) and gamma-activated sequence (GAS) sequences. Arrows indicate the polymerase chain reaction primers used for amplifying gliostatin/thymidine phosphorylase (GLS/TP) promoter containing the Sp1-binding site furthest upstream (A). Confluent fibroblast-like synoviocytes were incubated in the presence or absence of 300 nM mithramycin for 24 hours. Sp1 binding to the furthest upstream Sp1-binding site within the GLS/TP promoter was detected by ChIP assays. This binding was suppressed by treatment with mithramycin (B). Similar observations were obtained at least three times. bp, base pairs; MIT, mithramycin.