<i>Toxoplasma</i> infection impairs IFN-γ-induced acetylation of histones H3 and H4 at IFN-γ-responsive promoters in murine macrophages.

<p>(A) RAW264.7 macrophages were infected with <i>T. gondii</i> for 24 hours or were left non-infected, and were stimulated or not with IFN-γ during the final 16 hours. After cross-linking DNA-protein complexes, cell lysates were subjected to ChIP analysis using an anti-acetyl-H4 antibody and protein A agarose. A no-antibody control was run in parallel (wo Ab). After isolation of DNA from chromatin immunoprecipitates or from input cell lysates, fragments of the CIITA pIV or β-actin were amplified by real-time PCR. Amplicons were verified by agarose gel electrophoresis. Nc: PCR negative control: without template. (B+C) Acetylation of histones H4 (B) and H3 (C) at the CIITA pIV and β-actin after stimulation of MΦ with IFN-γ was analysed by ChIP as described above and was quantified according to the ratio (E_ChIP)^{ΔCPChIP(unstimulated – IFN-γ-treated)}/(E_input)^{ΔCPinput(unstimulated – IFN-γ-treated)}. Results are means ± S.E.M. from three independent experiments, significant differences between the acetylation in non-infected (n.i.) and infected (<i>T. gondii</i>) MΦ were identified by Student's <i>t</i>-test (**, <i>p</i><0.01). (D) The histone H3/H4 acetylation at the H2-Eβ and the GBP2 promoters of non-infected and <i>Toxoplasma</i>-infected MΦ was analysed by ChIP as described above (n = 2).