The distribution of H3K36 trimethylation differs between B cells versus plasma cells. A, the 11-kb IgH γ2a gene in the two cell lines representing the B cell is shown. B, the cells were fixed, and chromatin immunoprecipitation was performed using antibodies to RNAP-II and histone H3 across the IgH gene in either B cells or plasma cells. The distribution in each cell type is indicated. %IP, percentage immunoprecipitated. C, the profile of H3K36 trimethylation across the IgH γ2a gene.