Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; email:
Annu Rev Microbiol. 2018 Sep 8;72:163-184. doi: 10.1146/annurev-micro-090817-062444.
The stringent response to nutrient deprivation is a stress response found throughout the bacterial domain of life. Although first described in proteobacteria for matching ribosome synthesis to the cell's translation status and for preventing formation of defective ribosomal particles, the response is actually much broader, regulating many hundreds of genes-some positively, some negatively. Utilization of the signaling molecules ppGpp and pppGpp for this purpose is ubiquitous in bacterial evolution, although the mechanisms employed vary. In proteobacteria, the signaling molecules typically bind to two sites on RNA polymerase, one at the interface of the β' and ω subunits and one at the interface of the β' secondary channel and the transcription factor DksA. The β' secondary channel is targeted by other transcription regulators as well. Although studies on the transcriptional outputs of the stringent response date back at least 50 years, the mechanisms responsible are only now coming into focus.
营养缺乏的严格响应是一种在细菌生命领域中发现的应激响应。尽管最初在变形菌中被描述为匹配核糖体合成与细胞的翻译状态，并防止形成有缺陷的核糖体颗粒，但实际上该响应更为广泛，调节了数百个基因——有些是阳性的，有些是阴性的。利用信号分子 ppGpp 和 pppGpp 来实现这一目的在细菌进化中是普遍存在的，尽管所采用的机制有所不同。在变形菌中，这些信号分子通常结合到 RNA 聚合酶上的两个位点，一个在β'和ω亚基的界面上，另一个在β'二级通道和转录因子 DksA 的界面上。β'二级通道也被其他转录调节剂靶向。尽管对严格响应的转录输出的研究可以追溯到至少 50 年前，但负责的机制直到现在才开始引起关注。
