Skip to main content
. Author manuscript; available in PMC: 2013 Apr 1.
Published in final edited form as: Curr Opin Genet Dev. 2011 Dec 12;22(2):79–85. doi: 10.1016/j.gde.2011.11.001

Figure 3. CTCF role in facilitating long range interaction between an enhancer and promoter.

Figure 3

A. CTCF mediates interaction between two insulators which positively influences enhancer-promoter interaction. This model reflects the arrangement in the β-globin and APO loci [4;48]. B. CTCF interacts with an enhancer and target promoter and participates directly in long range interaction between them that leads to transcription activation. Examples of this arrangement have been recently been described [49]. C. CTCF interacts with an insulator and provides interaction with a promoter which in turn activates transcription. The INFG and MHC class II loci provide examples of this mechanism [51;53]. D. Insulator bound CTCF provides interaction with an enhancer which in turn interacts with a target promoter. This mechanism is utilized in the IgH locus [54;55]. Variants A, C and D can be incorporated into the concept of the active chromatin hub which provides an environment conducive to transcription activation. Designations are as in Figure 1.