A Dot Blot analysis was performed to test the cross reactivity of Anti-H3K27me3 polyclonal antibody (Catalog # CI1056) with peptides containing other modifications of histone H3 and H4 and the unmodified H3K27 sequence. One hundred to 0.2 pmol of the peptide containing the respective histone modification were spotted on a membrane. The antibody was used at a dilution of 1:5,000. This figure shows a high specificity of the antibody for the modification of interest. Please note that that antibody also recognizes the modification if S28 is phosphorylated.