Cebolla A, Sousa C, de Lorenzo V
Departamento de Genética and Departamento de Microbiología y Parasitología, Universidad de Sevilla, 41080 Seville, Spain.
Nucleic Acids Res. 2001 Feb 1;29(3):759-66. doi: 10.1093/nar/29.3.759.
Cascade regulatory circuits have been described that control numerous cell processes, and may provide models for the design of artificial circuits with novel properties. Here we describe the design of a transcriptional regulatory cascade to amplify the cell response to a given signal. We used the salicylate-responsive activators of Pseudomonas putida NahR of the naphthalene degradation plasmid NAH7 and XylS2, a mutant regulator of the TOL plasmid for catabolism of m-xylene and their respective cognate promoters Psal and PM: Control of the expression of xylS2 with the nahR/Psal system permitted either their selective activation with specific effectors for each protein or the simultaneous activation of both of them with salicylate. When cells face the common effector of the two regulators, both the increase in XylS2 concentration and the stimulation of its activity act synergistically on the PM: promoter, amplifying the gene expression capacity by at least one order of magnitude with respect to the individual systems. By changing the hierarchy of regulators, we showed that the specific features of the downstream regulator were crucial for the amplification effect. Directed changes in the effector profile of the regulators allowed the extension of the amplifying system to other molecular signals.
已经描述了控制众多细胞过程的级联调节回路，并且这些回路可能为设计具有新特性的人工回路提供模型。在此，我们描述了一种转录调节级联的设计，以放大细胞对给定信号的反应。我们使用了萘降解质粒NAH7的恶臭假单胞菌NahR的水杨酸酯响应激活剂以及XylS2，它是用于间二甲苯分解代谢的TOL质粒的突变调节因子，以及它们各自的同源启动子Psal和PM：用nahR/Psal系统控制xylS2的表达，既可以用每种蛋白质的特异性效应物对它们进行选择性激活，也可以用水杨酸同时激活它们。当细胞面对这两种调节因子的共同效应物时，XylS2浓度的增加及其活性的刺激对PM启动子具有协同作用，相对于单个系统，基因表达能力至少放大了一个数量级。通过改变调节因子的层次结构，我们表明下游调节因子的特定特征对于放大效应至关重要。调节因子效应物谱的定向改变使得放大系统能够扩展到其他分子信号。
