CpG methylation assay at the promoter and enhancer of Cd19 in cells at various differentiation stages. The level of CpG methylation was measured by bisulfite sequencing using genomic DNA derived from MEF, ES cells, monocytes (ER-MP20⁺ bone marrow cells), CD4⁻/CD8⁻ (DN) T cells, progenitors (CMP, LSK, CLP), pre-pro-B, early pro-B, pre-B, and mature B cells. The purification profile can be found in Figure S3. The assay was performed on 7 CpGs at the promoter (−300 to + 120) (A) and 8 at the enhancer (−2300 to −1650) (B). The numbers at the top of the panels represent the CpGs found at the promoter (1-7) or the enhancer (1-8) (the exact positions are indicated on the sequence in Figure S4). The numbers at the bottom represent base pairs relative to ATG. The PAX5 binding site is indicated as a horizontal bar. Major transcription start sites () were determined by RT-TDPCR (data not shown). A highly homologous region at the enhancer is indicated by .