Presence of di- and tri methylated H3K4 and acetylated H3 at ZAP70 promoter is associated with gene expression. (A) Native chromatin obtained from patient samples was digested using monococcal nuclease as outlined in Materials and methods. First sample was taken before the digestion and second following a digestion and spin to remove membranes and debris. Representative picture of pre- and post-digest chromatin is shown. Obtained digested native chromatin contains only mononucleosomes. (B) 100 μg of native chromatin obtained from ZAP70 positive or negative patient CLL cells was incubated with 10 μg of anti dimethyl H3K4 or control antibody; ChIP assay was carried out and R1 to R4 ZAP70 promoter fragments were amplified, n = 8. (C) 100 μg of native chromatin obtained from ZAP70 positive or negative patient CLL cells was incubated with 10 μg of anti trimethyl H3K4 or control antibody; ChIP assay was carried out and R1 to R4 ZAP70 promoter fragments were amplified, n = 8. (D) 100 μg of native chromatin obtained from ZAP70 positive or negative patient CLL cells was incubated with 10 μg of anti acetylated H3 or control antibody; ChIP assay was carried out and R1 to R4 ZAP70 promoter fragments were amplified, n = 8. Statistical analysis – Mann U Whitney where (*), (**) and (***) indicate P < 0.05, P < 0.001 and P < 0.001 respectively.