Ko M S, Takano T
Department of Microbiology, Keio University School of Medicine, Tokyo, Japan.
DNA. 1989 Mar;8(2):127-33. doi: 10.1089/dna.1.1989.8.127.
To investigate the function of a cloned gene, inducible enhancer/promoters are preferred for controlling the level of expression experimentally. Highly inducible gene expression systems with both low basal levels and enhanced maximal levels of expression are especially sought. We have developed a new expression system using a positive feedback mechanism. Glucocorticoid receptor cDNA was fused to the enhancer/promoter of mouse mammary tumor virus (MTV) to induce receptor production. Simultaneous introduction of this receptor plasmid into mouse Ltk- cells augmented the expression of the reporter gene linked with the MTV enhancer/promoter by 10- to 100-fold in an induced state, but did not significantly change the expression of that in an uninduced state. This novel system of gene expression is a good candidate for an efficient genetic switch.
为了研究克隆基因的功能，诱导型增强子/启动子更适合用于通过实验控制表达水平。人们尤其希望获得具有低基础水平和增强的最大表达水平的高度诱导型基因表达系统。我们利用正反馈机制开发了一种新的表达系统。将糖皮质激素受体cDNA与小鼠乳腺肿瘤病毒（MTV）的增强子/启动子融合以诱导受体产生。将该受体质粒同时导入小鼠Ltk-细胞，可使与MTV增强子/启动子相连的报告基因在诱导状态下的表达增加10至100倍，但在未诱导状态下对其表达没有显著影响。这种新型基因表达系统是一种高效基因开关的良好候选者。
