Fig. 4.

Role of STAT1 S727 phosphorylation in the activation of the gbp2 promoter by IFN-γ. BMDM, obtained from WT and STAT1 S727A mice, were treated with 10 ng/ml (240 units/ml) IFN-γ for the indicated time points, and formaldehyde-cross-linked chromatin was isolated. (A–D) IP of sonicated fragments was performed overnight with polyclonal Abs against CBP (A), hyperacetylated histone 4 (acH4) (B), IRF1 (C), and RNA Pol II (D). (E) Western blot analysis of whole-cell extracts from WT and S727A macrophages. The cells were treated with IFN-γ and analyzed for IRF1 protein levels. Equal loading was determined by reprobing the membrane with anti-panERK Abs.