Kim S J, Winokur T S, Lee H D, Danielpour D, Kim K Y, Geiser A G, Chen L S, Sporn M B, Roberts A B, Jay G
Laboratory of Chemoprevention, National Cancer Institute, Bethesda, Maryland 20892.
Mol Cell Biol. 1991 Oct;11(10):5222-8. doi: 10.1128/mcb.11.10.5222-5228.1991.
Human T-cell lymphotropic virus type I (HTLV-I) has been associated with an adult form of T-cell leukemia as well as tropical spastic paraparesis, a neurodegenerative disease. Adult T-cell leukemia patients express high levels of the type 1 isoform of transforming growth factor-beta (TGF-beta 1), which is mediated by the effects of the HTLV-I Tax transactivator protein on the TGF-beta 1 promoter. To understand further the regulation of TGF-beta 1 expression by Tax, we examined its expression in transgenic mice carrying the HTLV-I tax gene. We show that tumors from these mice and other tissues, such as submaxillary glands and skeletal muscle, which express high levels of tax mRNA selectively express high levels of TGF-beta 1 mRNA and protein. Moreover, TGF-beta 1 significantly stimulated the incorporation of tritiated thymidine into one of three cell lines derived from neurofibromas of tax-transgenic mice, which suggests that the excessive production of TGF-beta 1 may play a role in tumorigenesis and that these mice may serve as a useful model for studying the biological effects of TGF-beta in vivo.
人类嗜T细胞病毒I型(HTLV-I)与一种成人形式的T细胞白血病以及热带痉挛性截瘫(一种神经退行性疾病)有关。成人T细胞白血病患者表达高水平的转化生长因子β1型异构体(TGF-β1),这是由HTLV-I Tax反式激活蛋白对TGF-β1启动子的作用介导的。为了进一步了解Tax对TGF-β1表达的调控,我们检测了携带HTLV-I tax基因的转基因小鼠中TGF-β1的表达。我们发现,这些小鼠的肿瘤以及其他组织,如颌下腺和骨骼肌,它们高水平表达tax mRNA,同时也选择性地高水平表达TGF-β1 mRNA和蛋白。此外,TGF-β1显著刺激了氚标记胸腺嘧啶掺入来自tax转基因小鼠神经纤维瘤的三种细胞系之一,这表明TGF-β1的过量产生可能在肿瘤发生中起作用,并且这些小鼠可能成为研究TGF-β体内生物学效应的有用模型。