Figure 4

Model of miR-125b1 gene silencing, in which the absence of the nuclear factor CTCF is associated with DNA methylation of the CpG island, and the enrichment of repressive histone marks. In normal breast, CTCF might prevent the recruitment of the epigenetic silencing components, such as DNA methylation and repressive histone marks, also favors an open chromatin conformation (green color represent an open chromatin configuration). Meanwhile in breast cancer the loss of CTCF is associated with the CpG island (CGI) methylation and the gain of the repressive histone marks such as H3K9me3 and H3K27me3.