Novel NFAT sites that mediate activation of the interleukin-2 promoter in response to T-cell receptor stimulation.
The transcription factors NFAT and AP-1 have been shown to be essential for inducible interleukin-2 (IL-2) expression in activated T cells. NFAT has been previously reported to bind to two sites in the IL-2 promoter: in association with AP-1 at the distal antigen response element at -280 and at -135. On the basis of DNase I footprinting with recombinant NFAT and AP-1 proteins, gel shift assays, and transfection experiments, we have identified three additional NFAT sites in the IL-2 promoter. Strikingly, all five NFAT sites are essential for the full induction of promoter activity in response to T-cell receptor stimulation. Four of the five NFAT sites are part of composite elements able to bind AP-1 in association with NFAT. These sites display a diverse range of cooperativity and interdependency on NFAT and AP-1 proteins for binding. One of the NFAT sites directly overlaps the CD28-responsive element. We present evidence that CD28 inducibility is conferred by the AP-1 component in NFAT-AP-1 composite elements. These findings provide further insight into the mechanisms involved in the regulation of the IL-2 promoter.
Rooney
J W
JW
Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
Sun
Y L
YL
Glimcher
L H
LH
Hoey
T
T
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D018106:CD28 Antigens / Q000502:physiology; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism*; D007376:Interleukin-2 / Q000235:genetics*; D008213:Lymphocyte Activation; D051379:Mice; D008969:Molecular Sequence Data; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D011401:Promoter Regions, Genetic; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D015398:Signal Transduction; D018417:Th1 Cells / Q000502:physiology*; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
D018106:CD28 Antigens; D004268:DNA-Binding Proteins; D007376:Interleukin-2; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D011948:Receptors, Antigen, T-Cell; D018808:Transcription Factor AP-1; D014157:Transcription Factors