Transcriptional activation of the human TNF gene involves multiple regulatory elements whose functional properties vary between stimuli and cell types. Here we have used a COS-7 expression system to dissect the transactivating potential of NF-kappa B binding sites in the human TNF promoter region from other regulatory influences. In this model, NF-kappa B acts largely through a dense cluster of three binding sites located 600 nt upstream of the transcription start site. We show that the transcriptional activity of this complex is highly sensitive to the p65:p50 ratio that is expressed. We demonstrate that the AP-1 complex c-Jun/Fra2 is capable of binding to this region and that this inhibits the transactivating effects of NF-kappa B. These results are suggestive of a complex regulatory element that mediates fine control rather than acting as a simple on-off switch for TNF gene expression.

Original publication




Journal article


Biochemical and biophysical research communications

Publication Date





25 - 33


Wellcome Trust Centre for Human Genetics, Oxford University, Oxford OX3 7BN, United Kingdom.


COS Cells, Animals, Humans, Tumor Necrosis Factor-alpha, DNA-Binding Proteins, NF-kappa B, Proto-Oncogene Proteins c-fos, Proto-Oncogene Proteins c-jun, Protein Subunits, Transcription Factors, Transcription Factor AP-1, Sequence Deletion, Binding Sites, Fos-Related Antigen-2, Transcription Factor RelA, NF-kappa B p50 Subunit, Promoter Regions, Genetic, Transcriptional Activation