Interaction of NF-kappaB and NFAT with the interferon-gamma promoter

Interferon-gamma (IFN-gamma) is a pleiotropic lymphokine whose production is restricted to activated T cells and NK cells. Along with other cytokines, IFN-gamma gene expression is inhibited by the immunosuppressant cyclosporin A. We have previously identified an intronic enhancer region (C3) of the...

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Bibliographic Details
Published in:The Journal of biological chemistry 1997-11, Vol.272 (48), p.30412
Main Authors: Sica, A, Dorman, L, Viggiano, V, Cippitelli, M, Ghosh, P, Rice, N, Young, H A
Format: Article
Language:English
Subjects:
Base Sequence
Binding Sites
Calcineurin - physiology
DNA-Binding Proteins - metabolism
Enhancer Elements, Genetic
Humans
Interferon-gamma - genetics
NF-kappa B - metabolism
NFATC Transcription Factors
Nuclear Proteins
Promoter Regions, Genetic
Protein Binding
Proto-Oncogene Proteins - metabolism
Proto-Oncogene Proteins c-rel
Structure-Activity Relationship
T-Lymphocytes - metabolism
Tetradecanoylphorbol Acetate - pharmacology
Transcription Factors - metabolism
Transcription, Genetic
Tumor Cells, Cultured
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Summary:Interferon-gamma (IFN-gamma) is a pleiotropic lymphokine whose production is restricted to activated T cells and NK cells. Along with other cytokines, IFN-gamma gene expression is inhibited by the immunosuppressant cyclosporin A. We have previously identified an intronic enhancer region (C3) of the IFN-gamma gene that binds the NF-kappaB protein c-Rel and that shows partial DNA sequence homology with the cyclosporin A-sensitive NFAT binding site and the 3'-half of the NF-kappaB consensus site. Sequence analysis of the IFN-gamma promoter revealed the presence of two additional C3-related elements (C3-1P and C3-3P). In addition, an NF-kappaB site (IFN-gamma kappaB) was identified within the promoter region. Based on this observation, we have analyzed the potential role of NF-kappaB and NFAT family members in regulating IFN-gamma transcription. Electrophoretic mobility shift assay analysis demonstrated that after T cell activation, the p50 and p65 NF-kappaB subunits bind specifically to the newly identified IFN-gamma kappaB and C3-related sites. In addition, we identified the NFAT proteins as a component of the inducible complexes that bind to the C3-3P site. Site-directed mutagenesis and transfection studies demonstrate that calcineurin-inducible transcriptional factors enhance the transcriptional activity of the IFN-gamma promoter through the cyclosporin-sensitive C3-3P site, whereas NF-kappaB proteins functionally interact with the C3-related sites. In addition, when located downstream to the beta-galactosidase gene driven by the IFN-gamma promoter, the intronic C3 site worked in concert with both the IFN-gamma kappaB and the C3-3P site to enhance gene transcription. These results demonstrate that the coordinate activities of NFAT and NF-kappaB proteins are involved in the molecular mechanisms controlling IFN-gamma gene transcription.
ISSN:0021-9258
1083-351X