ChIP analysis of the human β-globin LCR in ln2 and human bone marrow cells. Immunoprecipitated and unbound (input) chromatin samples were subjected to duplex PCR analysis with one primer set specific for the human globin locus LCR and a second primer set specific for ZFP37 (ZFP) or pax6 gene. All PCR reactions were performed in parallel under conditions of linear amplification. Products were quantified by Phosphorimager. The level of enrichment of globin regions relative to the control and input samples is represented by bars with their corresponding SEM deviations. A value of 1 indicates that no enrichment was detected. (A) Duplex PCR ran in linear range of amplification. The same template DNA was subject to 29, 31, or 33 cycles of PCR amplification. Bars show the total intensity of the 2 PCR products and the line indicates the globin-control ratio. In the example, HS3 and pax6 primer sets were used. (B) ChIP performed with antiacetylated histone H3 (AcH3) and H4 (AcH4) Abs. Shown is the level of acetylation of HS3 (tgHS3) and HS4 (tgHS4) in ln2 HPCs and erythroid cells. Error bars indicate SEM deviations. (C) ChIP performed with anti-AcH3 and AcH4 Abs. Shown is the level of acetylation of HS3 and HS4 in human HPCs and erythroid cells. Error bars indicate SEM deviations.