An extraordinary stringent and sensitive light-switchable gene expression system for bacterial cells

Light-switchable gene expression systems provide transient, non-invasive and reversible means to control biological processes with high tunability and spatiotem-poral resolution. In bacterial cells, a few light-regulated gene expression systems based on photoreceptors and two-component regulatory systems(TCSs) have been reported, which respond to blue, green or red light[1-5]. These systems have already been used for a number of synthetic biology studies. Particularly, sophisticated temporal control of gene expression with unparalleled accuracy and precision can be achieved using these systems[1, 3-5]. However, their widespread usage is limited by a few drawbacks: limited portability due to multiple components[1-5], dependence on extraneous light-sen-sitive cofactors and appropriate cofactor synthesis genes[1,3-5],low yield of recombinant proteins due to weak induction efficiencies(much less than T7 expression systems)[1-5],lethal effect when gene product is toxic and difficulties in studying low-abundance proteins due to high leakage under the non-inducing conditions[1-5]. In addition, light-sensitive two-component systems are hardly adaptable to different promoters, as the gene regulation occurs only with specific cognate response regulator and promoter[1-5]. An ideal light-switchable gene expression system should be simple and easy to manipulate, and has high induction efficiency, low leakage, high sensitivity toward light, low toxicity, and low interference with endogenous proteins or genes[6].SCI(E)PubMed中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)LETTERyiyang@ecust.edu.cn7854-8572