Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland.
Biochem Soc Trans. 2013 Apr;41(2):542-7. doi: 10.1042/BST20120222.
DNA supercoiling and NAPs (nucleoid-associated proteins) contribute to the regulation of transcription of many bacterial genes. The horizontally acquired SPI (Salmonella pathogenicity island) genes respond positively to DNA relaxation, they are activated and repressed by the Fis (factor for inversion stimulation) and H-NS (histone-like nucleoid-structuring) NAPs respectively, and are positively controlled by the OmpR global regulatory protein. The ompR gene is autoregulated and responds positively to DNA relaxation. Binding of the Fis and OmpR proteins to their targets in DNA is differentially sensitive to its topological state, whereas H-NS binds regardless of the topological state of the DNA. These data illustrate the overlapping and complex nature of NAP and DNA topological contributions to transcription control in bacteria.
DNA 超螺旋和 NAPs（核小体相关蛋白）有助于调节许多细菌基因的转录。水平获得的 SPI（沙门氏菌致病性岛）基因对 DNA 松弛反应呈正响应，它们分别被 Fis（反转刺激因子）和 H-NS（组蛋白样核结构）NAPs 激活和抑制，并受到 OmpR 全局调节蛋白的正调控。ompR 基因是自身调控的，对 DNA 松弛反应呈正响应。Fis 和 OmpR 蛋白与 DNA 中靶标的结合对其拓扑状态具有不同的敏感性，而 H-NS 则与 DNA 的拓扑状态无关。这些数据说明了 NAP 和 DNA 拓扑结构对细菌转录调控的重叠和复杂性质。
