Part:BBa_K4619012
QS-LuxRm-PluxR
Quorum sensing is used by a large variety of bacteria to regulate gene expression in a cell-density-dependent manner.
Bacteria can synchronize population behavior using small molecules called autoinducers that are produced by cognate synthases and recognized by specific receptors. Quorum sensing plays a critical role in regulating diverse cellular functions in bacteria, including bioluminescence and so on.
The system is used to detect and express upstream signals without using positive feedback. The autoinducers (AHL), produced by the upstream system, can diffuse through the cell membrane into the growth medium. Here, we used a mutated LuxR–lux box system, called LuxRm-Pluxm. Pluxm promotor can not interact with wild-type LuxR protein. Compared with the wild-type LuxR–lux box system, the transcriptional activities of LuxRm-Pluxm are better, the background expression is more tightly regulated.
The J23119 promoter drives the expression of the luxRm gene continuously. If the upstream pathway is closed, AHL concentration is low, only showing slight leakage. As the upstream pathway opens, the autoinducers in the medium start to accumulate in a confined environment. When enough AHLs have accumulated in the medium, they enter the cell where they directly bind the LuxRm protein to activate msfGFP expression. High levels of AHLs activate the msfGFP expression, possessing a small volume and impressive performance simultaneously. A high intensity of light can be detected.
Remark: we use msfGFP as a convenient reporter in our experiments, the Nanoluc showing in the diagram refers to our design
Sequence and Features
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