| First Author | Defossez PA | Year | 2005 |
| Journal | J Biol Chem | Volume | 280 |
| Issue | 52 | Pages | 43017-23 |
| PubMed ID | 16230345 | Mgi Jnum | J:105907 |
| Mgi Id | MGI:3616953 | Doi | 10.1074/jbc.M510802200 |
| Citation | Defossez PA, et al. (2005) The human enhancer blocker CTC-binding factor interacts with the transcription factor Kaiso. J Biol Chem 280(52):43017-23 |
| abstractText | CTC-binding factor (CTCF) is a DNA-binding protein of vertebrates that plays essential roles in regulating genome activity through its capacity to act as an enhancer blocker. We performed a yeast two-hybrid screen to identify protein partners of CTCF that could regulate its activity. Using full-length CTCF as bait we recovered Kaiso, a POZ-zinc finger transcription factor, as a specific binding partner. The interaction occurs through a C-terminal region of CTCF and the POZ domain of Kaiso. CTCF and Kaiso are co-expressed in many tissues, and CTCF was specifically co-immunoprecipitated by several Kaiso monoclonal antibodies from nuclear lysates. Kaiso is a bimodal transcription factor that recognizes methylated CpG dinucleotides or a conserved unmethylated sequence (TNGCAGGA, the Kaiso binding site). We identified one consensus unmethylated Kaiso binding site in close proximity to the CTCF binding site in the human 5' beta-globin insulator. We found, in an insulation assay, that the presence of this Kaiso binding site reduced the enhancer-blocking activity of CTCF. These data suggest that the Kaiso-CTCF interaction negatively regulates CTCF insulator activity. |
