text: One mechanism of regulating CTCF is via methylation of its DNA sequence. CTCF protein is known to favourably bind to unmethylated sites, so it follows that methylation of CpG islands is a point of epigenetic regulation. An example of this is seen in the Igf2-H19 imprinted locus where methylation of the paternal imprinted control region (ICR) prevents CTCF from binding. A second mechanism of regulation is through regulating proteins that are required for fully functioning CTCF insulators. These proteins include, but are not limited to cohesin, RNA polymerase, and CP190.