Green J E
Laboratory of Molecular Oncology, National Cancer Institute, Frederick, Maryland 21702-1201.
Mol Cell Biol. 1991 Sep;11(9):4635-41. doi: 10.1128/mcb.11.9.4635-4641.1991.
Three lines of transgenic mice containing the human T-cell lymphotropic virus type I (HTLV-I) tax gene develop neurofibromas composed of perineural fibroblasts (S. H. Hinrichs, M. Nerenberg, R. K. Reynolds, G. Khoury, and G. Jay, Science 237:1340-1343, 1987; M. Nerenberg, S. H. Hinrichs, R. K. Reynolds, G. Khoury, and G. Jay, Science 237:1324-1327, 1987). Tumors and tumor cell lines derived from these mice produce neurite outgrowth from PC-12 cells and nerve growth factor (NGF), as determined by RNA (Northern) blot analysis and enzyme-linked immunosorbent assays. In vitro cotransfection studies demonstrate that Tax is able to trans activate the NGF promoter in NIH 3T3 fibroblast cells. The major cis-acting tax-responsive element in the NGF promoter (AGGGTGTGACGA) has 92% homology with a tax-responsive element contained within the 21-bp repeats of the HTLV-I long terminal repeat. The receptor for NGF is also expressed in the transgenic tumor cells, suggesting that Tax may activate an autocrine mechanism through the upregulation of NGF.
携带人类I型嗜T细胞病毒(HTLV-I)tax基因的三系转基因小鼠会发展出由神经周成纤维细胞组成的神经纤维瘤(S.H.欣里希斯、M.内伦贝格、R.K.雷诺兹、G.库里和G.杰伊,《科学》237:1340 - 1343,1987;M.内伦贝格、S.H.欣里希斯、R.K.雷诺兹、G.库里和G.杰伊,《科学》237:1324 - 1327,1987)。通过RNA(Northern)印迹分析和酶联免疫吸附测定确定,源自这些小鼠的肿瘤和肿瘤细胞系能使PC - 12细胞产生神经突生长并分泌神经生长因子(NGF)。体外共转染研究表明,Tax能够在NIH 3T3成纤维细胞中转激活NGF启动子。NGF启动子中的主要顺式作用tax反应元件(AGGGTGTGACGA)与HTLV - I长末端重复序列21 bp重复序列中包含的一个tax反应元件具有92%的同源性。NGF受体也在转基因肿瘤细胞中表达,这表明Tax可能通过上调NGF激活自分泌机制。