MYB binds and stimulates MIR155HG. (A) MYB occupancy within MIR155HG locus determined by ChIP, using anti-Myb (EP769Y) or control antibodies and carried out on cross-linked chromatin isolated from B-CLL cells (N = 6, average value indicated by black bars, patients included P40, P39, P47, P250, P254, and P255) and normal B cells (N = 6, white bars; “Patients and cells”). The y-axis indicates the relative occupancy of MYB. The x-axis marks the positions (in kilobases) of PCR amplicons relative to TSS (supplemental Data A). Black arrows indicate the positions of MYB DNA binding motifs; and black box, position of the CpG island (supplemental Data A). Error bars represent SEM of 3 independent experiments. *P < .05. (B) HeLa cells transiently transfected with pGL4.17 reporter vector containing the MYB binding site (−399 to −394 bp; black bars), its deletion mutant (gray bars), or a control reporter plasmid (Ctrl, white bars). Reporter vectors were transfected either alone (None) or cotransfected with MYB cDNA expression vector (MYB), and the luciferase activity at 48 hours (RLU) is shown relative to a control vector. The background activity was subtracted, and data were normalized to protein content. Average values and SD of at least 2 independent experiments are plotted.