Okret S, Poellinger L, Dong Y, Gustafsson J A
Proc Natl Acad Sci U S A. 1986 Aug;83(16):5899-903. doi: 10.1073/pnas.83.16.5899.
A cDNA clone for the rat glucocorticoid receptor (GR) was used to study mechanisms of GR mRNA regulation. Treatment of rat hepatoma culture cells with 0.5 microM dexamethasone caused a small, initial increase in the GR mRNA level after 6 hr as well as a 50% to 95% reduction of the GR mRNA level after 24 hr of incubation when studied by RNA blot hybridization. After 72 hr, the initial GR mRNA level was restored. The down-regulation of GR mRNA levels appears to be independent of protein synthesis, since it also was observed in the presence of cycloheximide. However, cycloheximide caused a 4-fold increase in intracellular levels of GR mRNA. Using an immunoprecipitation assay, we could demonstrate that the GR specifically interacts with a GR cDNA clone, which represents a 2.6-kilobase fragment of the 3' nontranslated region of the GR mRNA. Nuclease protection experiments indicate the presence of several internal GR-binding regions in the above fragment.
利用大鼠糖皮质激素受体（GR）的cDNA克隆来研究GR mRNA的调控机制。当通过RNA印迹杂交进行研究时，用0.5微摩尔/升地塞米松处理大鼠肝癌培养细胞，6小时后GR mRNA水平出现小幅初始升高，而在孵育24小时后GR mRNA水平降低了50%至95%。72小时后，GR mRNA的初始水平得以恢复。GR mRNA水平的下调似乎与蛋白质合成无关，因为在存在环己酰亚胺的情况下也观察到了这种现象。然而，环己酰亚胺使细胞内GR mRNA水平增加了4倍。使用免疫沉淀试验，我们能够证明GR与一个GR cDNA克隆特异性相互作用，该克隆代表GR mRNA 3'非翻译区的一个2.6千碱基片段。核酸酶保护实验表明上述片段中存在几个内部GR结合区域。
