ChIP assay. (A) RUVBL1 promoter region containing the high-affinity BCL6 binding site (0.705 kb). In BJAB cells BCL6 is bound (perhaps as part of a complex) to the region of the RUVBL1 promoter containing the putative BCL6 binding site (arrow) because DNA from this region is enriched in chromatin immunoprecipitated with anti-BCL6 (lane 5). Controls – no antibody (lane 1) and unrelated antibody, anti-rabbit IgG (lane 2) – do not enrich this genomic region. The positive (+) control is genomic DNA amplified with the same primers (lane 6). Lane 4 is 1 Kb Plus DNA Ladder (Invitrogen™, Life Technologies, Grand Island, NY); lane 7 is input. (B) RUVBL1 coding region (0.162 kb, arrow). Binding of BCL6 to a part of the coding region of RUVBL1 is not observed (lane 2) because there is no putative binding site. Input (lane 4) and the positive (+) control, genomic DNA amplified with the same primers (lane 5), show the anticipated 162 bp product (arrow). Lane 3 is 1 Kb Plus DNA Ladder (Invitrogen™).