Regulation of the human interleukin-2 receptor alpha chain promoter: activation of a nonfunctional promoter by the transactivator gene of HTLV-I.
We have characterized regulatory regions of the human IL-2 receptor alpha chain (IL2R alpha) promoter. 5' deletion constructs extending to -327 directed CAT expression in HTLV-I-infected T cells, which express IL2R alpha constitutively, and in Jurkat cells, which express IL2R alpha only after induction. Deletions to -267 and -265 were active only in HTLV-I-transformed T cells, but their activity in Jurkat cells was restored by cotransfection of a construct expressing the HTLV-I transactivator protein (tat-I). However, HTLV-I-infected human osteosarcoma cells do not express IL2R alpha-CAT constructs. Thus cell-type-specific factors are required for IL2R alpha expression, and direct or indirect interaction(s) between tat-I and a specific region of the IL2R alpha promoter may cause altered regulation. Tat-I also augments IL2-CAT expression under some conditions, suggesting possible autocrine or paracrine mechanisms for HTLV-I-induced leukemogenesis.
D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D017977:Deltaretrovirus / Q000235:genetics*; D005786:Gene Expression Regulation; D005796:Genes; D005814:Genes, Viral; D005822:Genetic Vectors; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism; D046911:Macromolecular Substances; D011401:Promoter Regions, Genetic; D011971:Receptors, Immunologic / Q000235:genetics*; D015375:Receptors, Interleukin-2
D007376:Interleukin-2; D046911:Macromolecular Substances; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2