FIGURE 5.
Genomic mapping of the Bmi-1 peaks from ChIP-seq dataset. HeLa cells overexpressing Bmi-1 were harvested for ChIP using anti-Bmi-1 antibody. The total population of the precipitated DNA was sequenced by ChIP-seq. The results of ChIP-seq are derived from 2 parallel experiments. All peaks were mapped to the genome. A, peaks were classified into four groups corresponding to: 1) the intergenic region, 2) the repeats only, 3) both gene-related regions and repeats, and 4) gene-related regions only. The distribution of these four types of peaks in each chromosome is shown in columns (the left y axis), and the average peak number in each chromosome is shown as curves (the right y axis). B, gene-related regions were subclassified into three types: up2k (indicates the region upstream to 2000 bp downstream of the transcription start site), intron or exon. The distribution of these three peak types was analyzed for each chromosome. Genes that contain a peak in the gene-related region were designated Bmi-1-targeted genes. C, all Bmi-1-targeted genes were classified by the indicated functions: apoptosis, cell cycle, development, HOX-related, and other. There were 55 apoptosis-related genes, 56 cell cycle-related genes, 158 development-related genes, and 12 HOX-related genes, consistent with the roles of Bmi-1 in proliferation, development, and tumorigenesis. All the groups of genes are enriched significantly (p < 0.01).