CTCF distribution and chromosomal breakpoint regions (BPR) around Ig enhancers and oncogenes involved in translocation with antigen receptor loci. (A) Genomic regions surrounding the human IgH enhancers. CTCF ChIP-Seq data (from the human GM12878 B lymphoblastoid cell line⁸¹) is shown above the localization of D_H, J_H, and C_H fragments. Green represents enhancers; and cyan, most common chromosomal BPRs. For the IGH locus, 2 common BPRs are annotated. eBL indicates endemic Burkitt lymphoma; sBL, sporadic Burkitt lymphoma; and HIV BL, HIV-induced Burkitt lymphoma. For scaling purposes, the position of Eμ (IGH), Ei (IGK), or HuEλ (IGL) enhancers was set to 0. (B) CTCF ChIP-Seq data (from the human GM12878 B lymphoblastoid cell line⁸¹) are shown for 3 genomic regions around oncogenes involved in translocations with antigen receptor loci. Locations of genes are shown on top, with the relevant oncogenes in blue and other genes in gray. The oncogene transcriptional start site was set to 0 for scaling purposes. Cyan indicates the most common chromosomal BPRs. BPRs linked to distinct B-cell malignancies are indicated as in panel A. For MYC, breakpoints found specifically in translocations with Ig light chain loci are annotated (IGK/L). Red bars represent the BCL6 CpG islands located in intron 1.