Interleukin-3 expression by activated T cells involves an inducible, T-cell-specific factor and an octamer binding protein.
Interleukin-3 (IL-3) is exclusively expressed by activated T and natural killer cells, a function that is tightly controlled both in a lineage-specific and in a stimulation-dependent manner. We have investigated the protein binding characteristics and functional importance of the ACT-1-activating region of the IL-3 promoter. This region binds an inducible, T-cell-specific factor over its 5' end, a site that is necessary for the expression of IL-3 in the absence of other upstream elements. Over its 3' end, it binds a factor that is ubiquitously and constitutively expressed. This factor is Oct-1 or an immunologically related octamer-binding protein, and it plays a role in coordinating the activity of several regulatory elements. These characteristics make the ACT-1 site analogous to the activating ARRE-1 site in the IL-2 promoter. Furthermore, and despite a lack of sequence homology, the promoters of IL-3 and IL-2 share an organizational pattern of regulatory elements that is likely to be important for the T-cell-specific expression of these genes.
Davies
K
K
Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115.
TePas
E C
EC
Nathan
D G
DG
Mathey-Prevot
B
B
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015245:Deoxyribonuclease BamHI; D015870:Gene Expression; D051863:Host Cell Factor C1; D006801:Humans; D007377:Interleukin-3 / Q000235:genetics*; D007938:Leukemia; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D050811:Octamer Transcription Factor-1; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D013601:T-Lymphocytes / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; C497692:HCFC1 protein, human; D051863:Host Cell Factor C1; D007377:Interleukin-3; D050811:Octamer Transcription Factor-1; C494165:POU2F1 protein, human; D014157:Transcription Factors; D004247:DNA; D015245:Deoxyribonuclease BamHI