The same inducible nuclear proteins regulates mitogen activation of both the interleukin-2 receptor-alpha gene and type 1 HIV

Both the interleukin-2 receptor-alpha (Tac, p55, IL-2Rα) gene and the long terminal repeat (LTR) of type 1 HIV are activated by various T cell mitogens. We now demonstrate that an inducible 86 kd nuclear protein termed HIVEN86A specifically binds to both the enhancer element of the HIV-1 LTR and a closely related 12 bp sequence present in the 5′ regulatory region (−267 to −256) of the IL-2Rα gene. The interaction of these binding sites with HIVEN86A and perhaps other cellular proteins such as NF-κB appears importantly involved in mitogen activation since the isolated IL-2Rα promoter binding site or single elements of the normally duplicated HIV-1 enhancer alone are sufficient to confer mitogen inducibility on an unresponsive heterologous promoter. Together these findings suggest that the normal action of an inducible nuclear DNA binding protein(s) involved in the regulation of IL-2Rα gene expression can be subverted by the HIV-1 provirus to promote activation of retroviral gene transcription.