Graduate Group in Biophysics, University of California, San Francisco, San Francisco, California 94158, USA.
Biotechnol Bioeng. 2011 Mar;108(3):666-75. doi: 10.1002/bit.22966. Epub 2010 Dec 1.
Two-component systems enable bacteria to sense changes in their environment and adjust gene expression in response. Multiple two-component systems could function as a combinatorial sensor to discriminate environmental conditions. A combinatorial sensor is composed of a set of sensors that are non-specifically activated to different magnitudes by many stimuli, such that their collective activity pattern defines the signal. Using promoter reporters and flow cytometry, we measured the response of three two-component systems in Escherichia coli that have been previously reported to respond to many environmental stimuli (EnvZ/OmpR, CpxA/CpxR, and RcsC/RcsD/RcsB). A chemical library was screened for the ability to activate the sensors and 13 inducers were identified that produce different patterns of sensor activity. The activities of the three systems are uncorrelated with each other and the osmolarity of the inducing media. Five of the seven possible non-trivial patterns generated by three sensors are observed. This data demonstrate one mechanism by which bacteria are able to use a limited set of sensors to identify a diverse set of compounds and environmental conditions.
两成分系统使细菌能够感知环境变化，并相应地调整基因表达。多个两成分系统可以作为组合传感器，以区分环境条件。组合传感器由一组传感器组成，这些传感器被许多刺激以不同的幅度非特异性地激活，使得它们的集体活性模式定义了信号。使用启动子报告基因和流式细胞术，我们测量了先前报道对许多环境刺激（EnvZ/OmpR、CpxA/CpxR 和 RcsC/RcsD/RcsB）有反应的三种大肠杆菌两成分系统的反应。对化学文库进行了筛选，以确定其激活传感器的能力，并确定了 13 种诱导剂，它们产生不同的传感器活性模式。这三个系统的活性彼此之间以及诱导介质的渗透压没有相关性。观察到五个由三个传感器生成的七个可能的非平凡模式。该数据证明了细菌能够使用有限的一组传感器来识别多种化合物和环境条件的一种机制。
