Activation of the granulocyte-macrophage colony-stimulating factor promoter in T cells requires cooperative binding of Elf-1 and AP-1 transcription factors.
The granulocyte-macrophage colony-stimulating factor (GM-CSF) gene has been studied extensively as a model system of transcriptional induction during T-lymphocyte activation. The GM-CSF gene is not expressed in resting peripheral blood T cells but is rapidly induced at the transcriptional level following activation through the cell surface T-cell receptor. A highly conserved 19-bp element located immediately 5' of the human GM-CSF TATA box (bp -34 to -52), herein called purine box 1 (PB1), has been shown to bind a T-cell nuclear protein complex and to be required for transcriptional induction of the GM-CSF gene following T-cell activation. The PB1 sequence motif is highly conserved in both human and murine GM-CSF genes. In this report, we demonstrate that the PB1 element alone confers inducibility on a heterologous promoter following transfection into human Jurkat T cells. In addition, we identify a major PB1 nuclear protein-binding complex that is not present in resting peripheral blood T cells but is rapidly induced following T-cell activation. Sequence analysis revealed that PB1 is composed of adjacent binding sites for Ets and AP-1 transcription factors. In vitro mutagenesis experiments demonstrated that both the Ets and AP-1 sites are required for binding of the inducible PB1 nuclear protein complex and for the transcriptional activity of this element and the GM-CSF promoter in activated T cells. Using antibodies specific for different Ets and AP-1 family members, we demonstrate that the major inducible PB1-binding activity present in activated T-cell nuclear extracts is composed of the Elf-1, c-Fos, and JunB transcription factors. Taken together, these results suggest that cooperative interactions between specific Ets and AP-1 family members are important in regulating inducible gene expression following T-cell activation.
Wang
C Y
CY
Department of Medicine, University of Chicago, Illinois 60637.
Bassuk
A G
AG
Boise
L H
LH
Thompson
C B
CB
Bravo
R
R
Leiden
J M
JM
D000328:Adult; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D002478:Cells, Cultured; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis / Q000378:metabolism; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D008213:Lymphocyte Activation; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D011401:Promoter Regions, Genetic; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; C512897:ELF1 protein, human; C512896:Elf1 protein, mouse; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D004247:DNA; D015500:Chloramphenicol O-Acetyltransferase