Differential induction of primary-response (TIS) genes in PC12 pheochromocytoma cells and the unresponsive variant PC12nnr5.
Differential induction of primary-response (TIS) genes in PC12 pheochromocytoma cells and the unresponsive variant PC12nnr5.
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DOI：
10.1016/s0021-9258(19)67608-8
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发表时间：
1991-03
期刊：
影响因子：
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通讯作者：
J. Altin;D. Kujubu;S. Raffioni;D. Eveleth;H. Herschman;R. Bradshaw
中科院分区：
文献类型：
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作者：
J. Altin;D. Kujubu;S. Raffioni;D. Eveleth;H. Herschman;R. Bradshaw
为了衡量它们传递的跨膜信号，比较了两种神经营养因子，神经生长因子(NGF)和碱性成纤维细胞生长因子(BFGF)，以及毒扁豆碱激动剂卡巴胆碱在大鼠嗜铬细胞瘤细胞系PC12和形态无反应变异体PC12nr5中诱导TIS(十四酰佛波酯诱导序列)转录本的能力，TIS转录本代表一系列即时早期反应基因。在这些细胞中，由NGF(Kujubu，D.A.，Lim，R.W.，Varnum，B.C.和Herschman，H.R.(1987)癌基因1,257-262,1987)诱导的三个基因TIS1(也称为NGFIB)，TIS8(也称为NGFIA)和TIS21，也被bFGF和卡巴胆碱诱导。在天然PC12细胞中，TIS8和TIS21在所有三种刺激下的表达水平相似，对十四酰佛波醇醋酸酯(TPA)也是如此。相反，NGF和TPA对TIS1的诱导作用很弱，只有在bFGF刺激后才能检测到，但对卡巴胆碱的诱导作用很强。因此，尽管所有这些药物都可以激活蛋白激酶(PK-C)，但至少有一个TIS基因显然可以被这些配体差异调控，这表明还必须存在替代的信号通路。与这一观点一致，bFGF和较小程度的NGF可以在PK-C被TPA下调的PC12细胞中引发TIS基因反应。在这种情况下，对卡巴胆碱(和TPA)的反应被有效地阻断。由于神经生长因子和碱性成纤维细胞生长因子都能刺激这些细胞中的突起生长，因此PK-C显然不是导致这些因子基因表达调控的信号转导的唯一机制。与这一模型一致的是，假定的蛋白激酶抑制剂K252a和鞘氨醇不抑制TIS基因对bFGF的反应。然而，这些药物也未能阻断TIS基因对氨基甲胆碱和TPA的反应，表明它们在这些条件下作为PK-C抑制剂是无效的。然而，NGF诱导的反应被K252a阻断，这表明该因子的机制中有一个独特的步骤，其他配体没有共享。鞘氨醇不能阻断NGF诱导的TIS。突变的PC12nnr5细胞对NGF和bFGF都没有形态上的反应。然而，TIS基因对碱性成纤维细胞生长因子的反应不受影响，而对NGF的反应则完全取消。对TPA的反应在数量上发生了改变，但在性质上没有改变；氨基甲胆碱的诱导作用在很大程度上被消除了，这显然是由于M受体减少了90%。
As a measure of the transmembrane signals that they transduce, two neurotrophic agents, nerve growth factor (NGF) and basic fibroblast growth factor (bFGF), and the muscarinic agonist carbachol were compared for their ability to induce TIS (tetradecanoyl phorbol acetate-inducible sequences) transcripts, representing a family of immediate early response genes, in the rat pheochromocytoma cell line PC12 and the morphologically unresponsive variant PC12nnr5. Three genes, TIS1 (also designated NGFIB), TIS8 (also designated NGFIA), and TIS21, induced in these cells by NGF (Kujubu, D.A., Lim, R.W., Varnum, B.C., and Herschman, H.R. (1987) Oncogene 1, 257-262, 1987), are also induced by bFGF and carbachol. In native PC12 cells the level of expression of TIS8 and TIS21 is similar for all three stimuli, as well as for tetradecanoyl phorbol acetate (TPA). In contrast, the induction of TIS1 by NGF and TPA is slight and is only just detectable after stimulation by bFGF, but is strong for carbachol. Thus, although all of these agents can stimulate protein kinase (PK-C), at least one TIS gene can apparently be differentially regulated by these ligands, suggesting that alternative signaling pathways must also exist. In keeping with this view, bFGF, and to a lesser degree NGF, can elicit a TIS gene response in PC12 cells in which PK-C has been down-regulated with TPA. The response to carbachol (and TPA) is effectively blocked under these conditions. Since both NGF and bFGF stimulate neurite outgrowth in such cells, PK-C is apparently not essential, i.e. does not represent the sole mechanism, for signal transduction leading to modulation of gene expression for these factors. Consistent with this model, putative protein kinase inhibitors, K252a and sphingosine, did not inhibit the TIS gene responses to bFGF. However, these agents also failed to block TIS gene responses to carbachol and TPA indicating that they were ineffective as PK-C inhibitors under these conditions. The NGF-induced response was, however, blocked by K252a indicating a unique step in the mechanism of this factor not shared by the other ligands. Sphingosine did not block TIS induction with NGF. The mutant cell line PC12 nnr5 does not respond morphologically to either NGF or bFGF. However, TIS gene responses to bFGF are unaffected, whereas those to NGF are completely abolished. The response to TPA is altered quantitatively but not qualitatively; the induction by carbachol is largely eliminated, apparently as a result of a 90% reduction in muscarinic receptors.(ABSTRACT TRUNCATED AT 400 WORDS)