CIITA and modified histones are stably bound at the <i>HLA-DRA</i> promoter after IFN-γ removal.

<p>(A) mRNA levels of <i>CIITA</i> and <i>HLA-DRA</i> were measured by qRT-PCR after A431 cells were treated with IFN-γ for 0 or 24 hrs (black bars), and after IFN-γ treated cells were washed and supplied with IFN-γ free media and cultured for an additional 24 to 72 hrs (grey bars). An additional but separate set of experiments were carried out for 120 hours (clear) and are shown. The results of three independent experiments were averaged and plotted with standard error. (B) ChIP for CIITA and each indicated histone modification, as well as a negative control IgG were conducted after A431 cells were treated as in A. ChIP assays were analyzed at the WXY box region. The qRT-PCR and ChIP values for the 0 and 24 hr IFN-γ treated samples in the left panels of each set are the same as those shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037554#pone-0037554-g001" target="_blank">Figure 1</a> as the data were generated from the same set of experiments and chromatin preparations, and are provided again only for comparison purposes.