Cellular Transcription Factors and Regulation of IL-2 Receptor Gene Expression by HTLV-I tax Gene Product
Expression of the interleukin-2 receptor (IL-2Rα) gene is activated by the transcriptional
activator protein, Tax (previously referred to as the tat gene product), encoded by the human
T-cell leukemia virus (HTLV-I). Multiple protein binding sites for specific DNA-protein
interactions were identified over the upstream IL-2Rα transcriptional regulatory sequences.
However, only one region, which includes the sequence motif GGGGAATCTCCC, was
required for activation by both the tax gene product and mitogenic stimulation. Remarkably …
activator protein, Tax (previously referred to as the tat gene product), encoded by the human
T-cell leukemia virus (HTLV-I). Multiple protein binding sites for specific DNA-protein
interactions were identified over the upstream IL-2Rα transcriptional regulatory sequences.
However, only one region, which includes the sequence motif GGGGAATCTCCC, was
required for activation by both the tax gene product and mitogenic stimulation. Remarkably …
Expression of the interleukin-2 receptor (IL-2Rα) gene is activated by the transcriptional activator protein, Tax (previously referred to as the tat gene product), encoded by the human T-cell leukemia virus (HTLV-I). Multiple protein binding sites for specific DNA-protein interactions were identified over the upstream IL-2Rα transcriptional regulatory sequences. However, only one region, which includes the sequence motif GGGGAATCTCCC, was required for activation by both the tax gene product and mitogenic stimulation. Remarkably, this sequence also bound the nuclear factor NFκB, which is important for induction of κ-immunoglobulin gene expression. A model is presented whereby regulation of cellular gene expression by the HTLV-I tax gene product occurs via an indirect mechanism that may involve a post-translational modification of preexistent cellular transcription factors.
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