@article{BrabletzPfeufferSchorretal.1993,
  author    = {Brabletz, Thomas and Pfeuffer, Isolde and Schorr, Elke and Siebelt, Friederike and Wirth, Thomas and Serfling, Edgar},
  title     = {Transforming growth factor \(\beta\) and cyclosporin A inhibit the inducible activity of the interleukin-2 gene in T cells through a noncanonical octamer-binding site},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31199},
  year      = {1993},
  abstract  = {Transforming growth factor \(\beta\) (TGF-\(\beta\)) has a growth-inhibitory effect on numerous different cell types of the immune system, including T lymphocytes. We show in this study that the inhibitory action of TGF-\(\beta\) on T lymphocytes is accompanied by a block of interleukin 2 (IL-2) gene expression which is mediated, at least in part, by inhibition of IL-2 promoter/enhancer activity. The functional analysis of cis-regulatory (protoenhancer) elements of the IL-2 enhancer/promoter region showed that the most TGF-\(\beta\)-responsive element maps to its so-called upstream promoter site. The proto-enhancer activity of the upstream promoter site element is also inhibited by cyclosporin A. The upstream promoter site DNA harbors two noncanonical, closely linked binding sequences for octamer and AP-1-like factors. Both sites are involved in the establishment of IL-2 enhancer activity. Since the activity of genuine octamer sites but not that of AP-1-binding sites is also impaired by TGF-\(\beta\) and cyclosporin A in E14 T lymphoma cells, we conclude that both immunosuppressives interfere with the activity but not the DNA binding of octamer factors in T lymphocytes.},
  language  = {en}
}