title: Negative regulation of the RelA/p65 transactivation function by the product of the DEK proto-oncogene.
abstract: NF-kappaB-mediated transcriptional activation is controlled at several levels including interaction with coregulatory proteins. To identify new proteins capable of modulating NF-kappaB-mediated activation, a cytoplasmic two-hybrid screen was performed using the p65 C-terminal transactivation domain as bait and identified the product of the DEK proto-oncogene. DEK is a ubiquitous nuclear protein that has been implicated in several types of cancer and autoimmune diseases. DEK appears to function in several nuclear processes including transcriptional repression and modulation of chromatin structure. Our data indicate that DEK functions as a transcriptional corepressor to repress NF-kappaB activity. DEK expression blocked p65-mediated activation of an NF-kappaB-dependent reporter gene and also inhibited TNFalpha-induced activation of the reporter gene. Chromatin Immunoprecipitation (ChIP) assays showed that DEK associates with the promoters of the NF-kappaB-regulated cIAP2 and IL-8 genes in untreated cells and dissociates from these promoters upon NF-kappaB binding in response to TNFalpha treatment. Moreover, the expression levels of an NF-kappaB-dependent reporter gene as well as the NF-kappaB-regulated Mcp-1 and IkappaBalpha genes is increased in DEK-/- cells compared with wild-type cells. ChIP assays on these promoters show enhanced and prolonged binding of p65 and increased recruitment of the P/CAF coactivator. Overall, these data provide further evidence that DEK functions to negatively regulate transcription.
authors.affiliation: Department of Biological Sciences and Undergraduate Honors Program, University of Toledo, Toledo, Ohio 43606, and Department of Genetics and Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
authors.forename: Morgan
authors.initials: M
authors.lastname: Sammons
authors.forename: Shan Shan
authors.initials: SS
authors.lastname: Wan
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Vogel
authors.forename: Edwin J
authors.initials: EJ
authors.lastname: Mientjes
authors.forename: Gerard
authors.initials: G
authors.lastname: Grosveld
authors.forename: Brian P
authors.initials: BP
authors.lastname: Ashburner
mesh_terms: D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000378:metabolism; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism; D015513:Oncogene Proteins / Q000378:metabolism*; D000075223:Poly-ADP-Ribose Binding Proteins; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D000090063:Proto-Oncogene Mas; D051996:Transcription Factor RelA / Q000096:biosynthesis* / Q000737:chemistry; D015533:Transcriptional Activation; D019076:Transgenes; D020798:Two-Hybrid System Techniques
chemical_list: D002868:Chromosomal Proteins, Non-Histone; C084738:DEK protein, human; C000715470:MAS1 protein, human; D016328:NF-kappa B; D015513:Oncogene Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D000090063:Proto-Oncogene Mas; C498143:RELA protein, human; D051996:Transcription Factor RelA