Tissue-specific activity of the gammac chain gene promoter depends upon an Ets binding site and is regulated by GA-binding protein.
The gammac chain is a subunit of multiple cytokine receptors (interleukin (IL)-2, IL-4, IL-7, IL-9, and IL-15), the expression of which is restricted to hematopoietic lineages. A defect in gammac leads to the X-linked severe combined immunodeficiency characterized by a block in T cell differentiation. In order to better characterize the human gammac promoter and define the minimal tissue-specific promoter region, progressive 5'-deletion constructs of a segment extending 1053 base pairs upstream of the major transcription start site were generated and tested for promoter activity in various hematopoietic and nonhematopoietic cell types. The -1053/+34 construct allowed promoter activity only in cells of hematopoietic origin, and tissue specificity was conserved in all other constructs tested. The region downstream of -90 appeared critical for basal promoter activity. It contains two potential Ets binding sites conserved in the murine gammac promoter gene, one of which was found essential for functional promoter activity as determined by mutational analysis. The functional Ets binding site was found to bind Ets family proteins, principally GA-binding protein and Elf-1 and could be transactivated by GABPalpha and -beta synergistically. These results indicate that, as already reported for the IL2Rbeta promoter, GA-binding protein is an essential component of gammac basal promoter activity. Although GABP expression is not restricted to the hematopoietic lineage, its interaction with other specific factors may contribute to the tissue-specific expression of the gammac gene.
Markiewicz
S
S
INSERM U429, Hôpital Necker-Enfants Malades, 149 rue de Sèvres, 75743 Paris Cedex 15, France.
Bosselut
R
R
Le Deist
F
F
de Villartay
J P
JP
Hivroz
C
C
Ghysdael
J
J
Fischer
A
A
de Saint Basile
G
G
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002051:Burkitt Lymphoma; D002460:Cell Line; D002999:Clone Cells; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000378:metabolism; D051268:GA-Binding Protein Transcription Factor; D006367:HeLa Cells; D006801:Humans; D007694:Killer Cells, Natural; D007951:Leukemia, Myeloid; D015458:Leukemia, T-Cell; D046911:Macromolecular Substances; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D050783:Proto-Oncogene Proteins c-ets; D018121:Receptors, Cytokine / Q000096:biosynthesis* / Q000235:genetics*; D011994:Recombinant Proteins / Q000096:biosynthesis; D017384:Sequence Deletion; D012689:Sequence Homology, Nucleic Acid; D016511:Severe Combined Immunodeficiency / Q000235:genetics / Q000276:immunology; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D014960:X Chromosome
D017931:DNA Primers; D004268:DNA-Binding Proteins; C512897:ELF1 protein, human; C512896:Elf1 protein, mouse; D051268:GA-Binding Protein Transcription Factor; C495658:Gabpb1 protein, mouse; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D018121:Receptors, Cytokine; D011994:Recombinant Proteins; D014157:Transcription Factors