By DNase I hypersensitivity analysis, we have identified an inducible, cyclosporin A-sensitive enhancer located 3' of the interleukin-4 (IL-4) gene. The enhancer binds the Th2-specific transcription factor GATA3 in vivo but is not perceptibly influenced by the absence of a second Th2-specific factor, cMaf. The antigen-inducible transcription factor NFAT1 binds the IL-4 enhancer and the IL-4 promoter only in stimulated Th2 cells; conversely, NFAT1 binds to the interferon (IFN)-γ, promoter only in stimulated Th1 cells. Our results support a model whereby transcription factors such as NFAT1, which are nonselectively induced in antigen-stimulated T cells, gain access to cytokine regulatory regions only in the appropriate subset of differentiated T cells in vivo. This restricted access enables antigen-dependent and subset-specific transcription of cytokine genes.
Bibliographical noteFunding Information:
We thank M. J. Pazin, W. C. Forrester, and members of the laboratory for valuable discussions; B. S. Parekh and T. Maniatis for the ChIP protocol; H. A. Young for IFN-γ genomic clones; and J. I. Kim and L. H. Glimcher for cMaf −/− mice. We also thank Genetics Institute for their generous gift of recombinant IL-12 and anti-IL-12 antibodies and the National Cancer Institute–Biological Response Modifiers Program for anti-IL-4 antibodies. This work was supported by National Institutes of Health grants R01 CA42471, R01 AI44432, and P01 AI35297 (to A. R.). S. A. is a Howard Hughes Medical Institute Predoctoral Fellow and a Ryan Foundation Fellow. O. A. is a Postdoctoral Fellow of the Cancer Research Institute. A. R. was a Stohlman scholar of the Leukemia Society of America.