title: The p65 (RelA) subunit of NF-kappaB interacts with the histone deacetylase (HDAC) corepressors HDAC1 and HDAC2 to negatively regulate gene expression.
abstract: Regulation of NF-kappaB transactivation function is controlled at several levels, including interactions with coactivator proteins. Here we show that the transactivation function of NF-kappaB is also regulated through interaction of the p65 (RelA) subunit with histone deacetylase (HDAC) corepressor proteins. Our results show that inhibition of HDAC activity with trichostatin A (TSA) results in an increase in both basal and induced expression of an integrated NF-kappaB-dependent reporter gene. Chromatin immunoprecipitation (ChIP) assays show that TSA treatment causes hyperacetylation of the wild-type integrated NF-kappaB-dependent reporter but not of a mutant version in which the NF-kappaB binding sites were mutated. Expression of HDAC1 and HDAC2 repressed tumor necrosis factor (TNF)-induced NF-kappaB-dependent gene expression. Consistent with this, we show that HDAC1 and HDAC2 target NF-kappaB through a direct association of HDAC1 with the Rel homology domain of p65. HDAC2 does not interact with NF-kappaB directly but can regulate NF-kappaB activity through its association with HDAC1. Finally, we show that inhibition of HDAC activity with TSA causes an increase in both basal and TNF-induced expression of the NF-kappaB-regulated interleukin-8 (IL-8) gene. Similar to the wild-type integrated NF-kappaB-dependent reporter, ChIP assays showed that TSA treatment resulted in hyperacetylation of the IL-8 promoter. These data indicate that the transactivation function of NF-kappaB is regulated in part through its association with HDAC corepressor proteins. Moreover, it suggests that the association of NF-kappaB with the HDAC1 and HDAC2 corepressor proteins functions to repress expression of NF-kappaB-regulated genes as well as to control the induced level of expression of these genes.
authors.affiliation: Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors.forename: B P
authors.initials: BP
authors.lastname: Ashburner
authors.forename: S D
authors.initials: SD
authors.lastname: Westerheide
authors.forename: A S
authors.initials: AS
authors.lastname: Baldwin
mesh_terms: D016475:3T3 Cells; D000107:Acetylation; D000818:Animals; D001665:Binding Sites; D015152:Blotting, Northern; D015153:Blotting, Western; D019556:COS Cells; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D006367:HeLa Cells; D056284:Histone Deacetylase 1; D056464:Histone Deacetylase 2; D006655:Histone Deacetylases / Q000378:metabolism*; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism* / Q000502:physiology*; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D012097:Repressor Proteins; D051996:Transcription Factor RelA; D015533:Transcriptional Activation; D014162:Transfection
chemical_list: D002843:Chromatin; D004791:Enzyme Inhibitors; D006877:Hydroxamic Acids; D016328:NF-kappa B; D012097:Repressor Proteins; D051996:Transcription Factor RelA; C012589:trichostatin A; D008156:Luciferases; C110550:HDAC1 protein, human; C533424:Hdac2 protein, mouse; D056284:Histone Deacetylase 1; D056464:Histone Deacetylase 2; D006655:Histone Deacetylases