Ye P, Laszkiewicz I, Wiggins R C, Konat G W
Department of Anatomy, West Virginia University School of Medicine, Morgantown 26505-9128.
J Neurosci Res. 1994 Apr 15;37(6):683-90. doi: 10.1002/jnr.490370603.
The treatment of rat glioma C6 cells with 10 microM isoproterenol (Ipt) for 4 days upregulated the expression of the myelin-associated glycoprotein (MAG) gene by approximately 55-fold over the control value. The constant presence of Ipt in the medium was required for the maximal upregulation, as time-restricted exposures to the drug produced only partial, or no upregulation of the gene. No difference in the MAG mRNA stability could be detected in Ipt-treated vs untreated cells indicating that the drug upregulates the MAG gene at transcriptional level. Serum (FCS) strongly attenuated the response of the MAG gene to Ipt. The stimulatory effect of Ipt was profoundly reduced by spermine and H-89, indicating that protein kinase A-dependent protein phosphorylation is involved in the MAG gene activation. Within 30 min after Ipt administration, the c-fos gene was upregulated by 10-fold, and thereafter, its message level decreased and stabilized at approximately 3-fold over control. In contrast, the c-jun gene was downregulated to approximately 20% of control within 30 min after Ipt administration. Subsequently, its message level rose and fell once again within 12 h to approximately half of control, and returned to control level within 72 h.(ABSTRACT TRUNCATED AT 250 WORDS)
用10微摩尔异丙肾上腺素（Ipt）处理大鼠胶质瘤C6细胞4天，可使髓鞘相关糖蛋白（MAG）基因的表达比对照值上调约55倍。培养基中持续存在Ipt是实现最大上调所必需的，因为限时接触该药物仅产生部分上调或不产生基因上调。在Ipt处理的细胞与未处理的细胞中未检测到MAG mRNA稳定性的差异，这表明该药物在转录水平上调MAG基因。血清（FCS）强烈减弱了MAG基因对Ipt的反应。精胺和H - 89显著降低了Ipt的刺激作用，表明蛋白激酶A依赖性蛋白磷酸化参与了MAG基因的激活。给予Ipt后30分钟内，c - fos基因上调了10倍，此后，其信息水平下降并稳定在比对照高约3倍的水平。相比之下，给予Ipt后30分钟内，c - jun基因下调至对照的约20%。随后，其信息水平在12小时内再次上升和下降至对照的约一半，并在72小时内恢复到对照水平。（摘要截短于250字）
