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Mol Immunol. 2009 Aug;46(13):2706-13. doi: 10.1016/j.molimm.2009.05.024. Epub 2009 Jun 11.

CCAAT/enhancer binding proteins alpha and beta regulate the tumor necrosis factor receptor 1 gene promoter.

Author information

1
Departments of Oncology and Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, 53706, United States.

Abstract

CCAAT/enhancer binding protein (C/EBP) transcription factors play essential roles in regulating an array of cellular processes, including differentiation, energy metabolism, and inflammation. In this report we demonstrate that both C/EBPalpha and C/EBPbeta activate the promoter driving transcription of the tumor necrosis factor receptor 1 (TNFR1). TNFR1 is the major receptor for tumor necrosis factor (TNF), a critical cytokine mediator of the inflammatory response. Although the TNFR1 protein has been shown to be regulated through post-translational modifications, very little is known about the transcriptional regulation of the TNFR1 gene. Here we have identified a specific C/EBP binding site within the TNFR1 promoter, and shown that this site is required for both C/EBPalpha and C/EBPbeta activation of the promoter in reporter gene assays. Furthermore, we show that both C/EBPalpha and C/EBPbeta are bound to the TNFR1 promoter in cells using chromatin immunoprecipitation assays. Finally, we demonstrate that reducing the level of C/EBPalpha and C/EBPbeta expression in cells using siRNA technology leads to decreased expression of the TNFR1 protein. These results suggest that the C/EBPalpha and C/EBPbeta transcription factors enhance expression of the TNFR1 protein in cells. Given that TNF and C/EBPbeta are known to activate each other's expression, C/EBPbeta may greatly amplify the initial TNF signal through a positive auto-regulatory mechanism.

PMID:
19523687
PMCID:
PMC2724677
DOI:
10.1016/j.molimm.2009.05.024
[Indexed for MEDLINE]
Free PMC Article

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