ChIP assays were performed using HeLa cells, the Bioss antibody against H3K27me1 (Cat. No. bs-53108R) and optimized PCR primer sets for qPCR. ChIP was performed using sheared chromatin from 100,000 cells. A titration of the antibody consisting of 1, 2, 5 and 10 μg per ChIP experiment was analyzed. IgG (2 μg/IP) was used as negative IP control. QPCR was performed with primers for the promoter and the coding region of the active gene GAPDH used as a negative and a positive control target, respectively. The figure shows the recovery, expressed as a % of input (the relative amount of immunoprecipitated DNA compared to input DNA after qPCR analysis).