Expression of the pX gene products (p40(tax), p27(rex) and p21(X-III) of human T cell leukemia virus type 1 (HTLV-1), which is known to be a causative agent of adult T cell lymphoma/leukemia, induces expression of the interleukin-2 receptor α chain (IL-2Rα) on infected T cells. Comparison of IL-2Rα promoter activities has revealed that the transcriptional activation of the promoter alone cannot explain the large numbers of IL-2Rα expressed on HTLV-1 infected cells. We found that the rates of the IL-2Rα mRNA degradation were greatly reduced in pX-positive cells as compared with pX-negative cells. Simultaneous transfection of the expression vector plasmid containing IL-2Rα cDNA and similar plasmids containing various pX sequences showed that p27(rex) elongated the half life of IL-2Rα mRNA. As p27(rex) did not affect the transport of the IL-2Rα mRNA from nucleus to cytoplasm, prolongation of the IL-2Rα mRNA half life by p27(rex) is ascribed to stabilization of the mRNA. Experiments using deletion mutants and chimeric constructs of the IL-2Rα cDNA demonstrated that the coding sequence but not the 5' or 3' untranslated region of the IL-2Rα mRNA sequence is responsible for its protection by p27(rex).
|出版ステータス||Published - 1990|
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