Figure 1. Features of CTCF binding sites in the genome.
CTCF binding sites are associated with different genetic elements. The majority of sites are intergenic and co-localize with cohesin. In addition, a fraction of CTCF binding sites are located near RNA polymerase III (RNAPIII) type II genes (e.g. tRNA and SINE elements) and ETC loci, suggesting that TFIIIC and CTCF may cooperate in some aspects of the function of this protein. The 12 bp consensus sequence of CTCF sites is embedded within binding modules 2 and 3 as determined by the ChIP-exo technique. DNA methylation (filled red ball) of cytosine residues occurs at positions 2 and 12 of the consensus sequence in a subset of CTCF sites.