Fig. 7.

SAHA pretreatment impaired IFN-γ-induced histone acetylation of B7-H1 gene promoter. a HGC27 cells were pretreated with either DMSO or 2 μM SAHA for 8 h before stimulation with 50 ng/ml IFN-γ for 3 h. ChIP was performed using anti-H3K9Ac followed by quantification of immunoprecipitated B7-H1 gene promoter through PCR. H3K9Ac enrichment was determined by the percent input method. IFN-γ-induced upregulation of H3K9Ac was calculated as the ratio of H3K9Ac enrichment at post-stimulation to that at pre-stimulation. b The correlative relationship between enrichment of H3K9Ac at the promoters of B7-H1 gene and relative B7-H1 mRNA transcription in the same cell populations mentioned in A. X-axis stood for the mean value of enrichment of H3K9Ac at all the promoters of B7-H1 gene. Y-axis stood for B7-H1 mRNA expression relative to pre-stimulation level. a, b Experiments were repeated three times. **p < 0.001, *p < 0.05