Strauch M A, Hoch J A
Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California 92037.
Mol Microbiol. 1993 Feb;7(3):337-42. doi: 10.1111/j.1365-2958.1993.tb01125.x.
When Bacillus subtilis encounters a nutrient-depleted environment, it expresses a wide variety of genes that encode functions in alternative pathways of metabolism and energy production. Expression of these genes first occurs during the transition from active growth into stationary phase and is controlled by a class of proteins termed transition-state regulators. In several instances, a given gene is redundantly controlled by two or more of these regulators and many of these regulators control genes in numerous different pathways. The AbrB, Hpr and Sin proteins are the best-studied examples of these regulatory molecules. Their role is to prevent inappropriate and possibly detrimental functions from being expressed during exponential growth when they are not needed. They serve as elements integrating sporulation with ancillary stationary-phase phenomena and appear to participate in the timing of early sporulation events and in fine-tuning the magnitude of gene expression in response to specific environmental conditions.
当枯草芽孢杆菌遇到营养耗尽的环境时，它会表达多种基因，这些基因编码参与代谢和能量产生替代途径的功能。这些基因的表达首先发生在从活跃生长向稳定期转变的过程中，并受一类称为过渡态调节因子的蛋白质控制。在几种情况下，一个特定基因由两个或更多这些调节因子冗余控制，并且许多这些调节因子控制众多不同途径中的基因。AbrB、Hpr和Sin蛋白是这些调节分子中研究得最充分的例子。它们的作用是防止在指数生长期不需要时表达不适当且可能有害的功能。它们作为将芽孢形成与辅助稳定期现象整合的元件，似乎参与早期芽孢形成事件的时间安排，并参与微调基因表达的幅度以响应特定环境条件。
