Figure 3. OspF is chromatin-bound and modulates HP1γ chromatin association at its target immune genes.

1. HeLa cells were transfected with the indicated plasmids and stimulated by TNF at the indicated times. Chromatin immunoprecipitation experiments (ChIP) were performed using anti-OspF antibodies. Enrichment in chromatin was quantified by qPCR using indicated primers at the IL8, CD44, and NFKBIA genes. Enrichment values are the mean of three independent experiments. *P < 0.05 when compared to the non-stimulated cells (ns).
2. OspF modulates HP1γ chromatin association. HeLa cells were infected with the Shigella flexneri invasive strain (WT) or the OspF-deficient strain (ospF). ChiPs were performed using anti-HP1γ antibodies or mouse IgG as control. Enrichment in chromatin was quantified by qPCR using indicated primers at the IL8, NFKB1, and NFKBIA genes (Pr, proximal promoter; e2, exon 2). Enrichment values are the mean of three independent experiments. Significance of the differences was estimated using Student's t-test with a threshold at 5%.