Histone acetylation regulates p21WAF1 expression in human colon cancer cell lines

Figure 3 HDAC inhibitors induced accumulation of acety-lated histones H3 and H4 in chromatin associated with p21^WAF1 gene. A: PCR products for the 1st set primer of p21^WAF1; B: PCR products for the 2nd set primer of p21^WAF1; C: The figure in A and B was scanned and quantified by using IMAGE analysis software. The ratio between input DNA and precipitated DNA was calculated for each treatment and primer set. The increase after treatment with either TSA or sodium butyrate was calcu-lated from indicated ratios. PCR products of the 2 nd primer were not visualized on agarose gel before treatment with HDAC inhibitor, so it could not be calculated. Input DNA, lanes 1-4: Soluble chromatin was immunoprecipitated with antiacetylated histone H3 antibody; lanes 5-8: Soluble chro-matin was immunoprecipitated with antiacetylated histone H4 antibody; lanes 9-12: Normal rabbit serum as negative control; lanes 13-16, 1, 5, 9, 13: PBS control; lanes 2, 6, 10, 14: Alcohol control; lanes 3, 7, 11, 15: TSA 1 μmol/L, 24 h; lanes 4, 8, 12, 16: NaBu 5 mmol/L, 24 h.