Allele-specific chromatin remodeling of the tumor necrosis factor-alpha promoter.
The -863 C/A polymorphism in the tumor necrosis factor-alpha (TNF-alpha) promoter has been suggested to influence TNF-alpha expression. Here we elucidated the molecular mechanisms underlying the allele-specific regulation of TNF-alpha gene expression under basal and LPS-stimulated conditions in THP-1 cells and in human primary macrophages. We show that the binding of two NF-kappaB complexes, the p50/p50 homodimer and the p50/p65 heterodimer, was upregulated upon LPS stimulation. Both complexes bound to the C-allele whereas the A-allele only bound the p50/p65 complex. Two DNase I hypersensitive sites appeared in the TNF-alpha promoter after LPS stimulation of THP-1 cells. DNase I hypersensitivity of the TNF-alpha promoter was also analyzed in human monocytes prepared from individuals of different -863C/A genotype. Hypersensitivity was increased in the promoter harboring the mutant A-allele, particularly after LPS stimulation. In summary, binding of transcription factor NF-kappaB to the TNF-alpha promoter is associated with allele-specific remodeling of chromatin structure.
Skoog
Tiina
T
Atherosclerosis Research Unit, King Gustaf V Research Institute, Karolinska Institute, Karolinska University Hospital Solna, S-171 76 Stockholm, Sweden.
Hamsten
Anders
A
Eriksson
Per
P
D000483:Alleles; D002478:Cells, Cultured; D042002:Chromatin Assembly and Disassembly / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D009000:Monocytes / Q000187:drug effects / Q000502:physiology*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha