Repression of gene expression by unphosphorylated NF-κB p65 through epigenetic mechanisms

  1. Jie Dong,
  2. Eijiro Jimi1,
  3. Haihong Zhong2,
  4. Matthew S. Hayden, and
  5. Sankar Ghosh3
  1. Department of Immunobiology and Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA

Abstract

Cells from a “knock-in” mouse expressing a NF-κB p65 mutant bearing an alanine instead of serine at position 276 (S276A) display a significant reduction of NF-κB-dependent transcription, even though the mutant p65 forms appropriate complexes that translocate normally to the nucleus and bind to DNA. Surprisingly, however, instead of the expected embryonic lethality from hepatocyte apoptosis seen in the absence of NF-κB activity, the S276A knock-in embryos die at different embryonic days due to variegated developmental abnormalities. We now demonstrate that this variegated phenotype is due to epigenetic repression resulting from the recruitment of histone deacetylases by the nonphosphorylatable form of NF-κB into the vicinity of genes positioned fortuitously near NF-κB-binding sites. Therefore, unphosphorylated nuclear NF-κB can affect expression of genes not normally regulated by NF-κB through epigenetic mechanisms.

Keywords

Footnotes

  • 1 Present addresses: Division of Molecular Signaling and Biochemistry, Department of Biosciences, Kyushu Dental College, 2-6-1 Manazuru, Kokura-kita-ku, Kitakyushu-shi, 803-8580, Japan;

  • 2 Curagen Corporation, 555 Long Wharf Road, New Haven, CT 06511, USA.

  • 3 Corresponding author.

    3 E-MAIL sankar.ghosh{at}yale.edu; FAX (203) 737-1764.

  • Supplemental material is available at http://www.genesdev.org.

  • Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.1657408.

    • Received January 31, 2008.
    • Accepted March 11, 2008.

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