Enhanceosome

Structural model of the enhanceosome. Double-stranded DNA is shown in green and pink; the ATF-2/c-Jun coiled-coil DNA binding domain is shown in purple; interferon response factors are shown in beige; and NF kappa B is shown in orange (p105 subunit) and blue (p65 subunit).

The enhanceosome is a higher-order protein complex assembled at the enhancer and regulates expression of a target gene.[1] The binding and assembly of the activating proteins is cooperative due to energetically favorable protein-protein interactions formed in the complex.

The best known example of the enhanceosome acts on the human interferon-beta gene, which is upregulated in cells that are infected by viruses.[2] Three activator proteins - NF-κB, an interferon activator protein such as IRF-3, and the ATF-2/c-Jun complex - cooperatively bind to the upstream enhancer region upon viral infection. The interaction is mediated by a fourth protein HMG-I, which assists in stabilizing the complex by promoting inter-protein interactions. The assembled enhanceosome recruits transcriptional machinery such as RNA polymerase to the promoter region to initiate gene expression.

External links

References

  1. ↑ Merika, M; Thanos, D (Apr 2001). "Enhanceosomes.". Current opinion in genetics & development 11 (2): 205–8. doi:10.1016/s0959-437x(00)00180-5. PMID 11250145.
  2. ↑ Panne, D (Apr 2008). "The enhanceosome.". Current opinion in structural biology 18 (2): 236–42. doi:10.1016/j.sbi.2007.12.002. PMID 18206362.