Negative regulation of the RelA/p65 transactivation function by the product of the DEK proto-oncogene.
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.
Sammons
Morgan
M
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.
Wan
Shan Shan
SS
Vogel
Nancy L
NL
Mientjes
Edwin J
EJ
Grosveld
Gerard
G
Ashburner
Brian P
BP
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
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