Jayaraman Premkumar, Yeoh Jing Wui, Zhang Jingyun, Poh Chueh Loo
Department of Biomedical Engineering, Faculty of Engineering , National University of Singapore , Singapore 117583.
NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute , National University of Singapore , Singapore 117456.
ACS Synth Biol. 2018 Nov 16;7(11):2627-2639. doi: 10.1021/acssynbio.8b00280. Epub 2018 Nov 6.
To program cells in a dynamic manner, synthetic biologists require precise control over the threshold levels and timing of gene expression. However, in practice, modulating gene expression is widely carried out using prototypical ligand-inducible promoters, which have limited tunability and spatiotemporal resolution. Here, we built two dual-input hybrid promoters, each retaining the function of the ligand-inducible promoter while being enhanced with a blue-light-switchable tuning knob. Using the new promoters, we show that both ligand and light inputs can be synchronously modulated to achieve desired amplitude or independently regulated to generate desired frequency at a specific amplitude. We exploit the versatile programmability and orthogonality of the two promoters to build the first reprogrammable logic gene circuit capable of reconfiguring into logic OR and N-IMPLY logic on the fly in both space and time without the need to modify the circuit. Overall, we demonstrate concentration- and time-based combinatorial regulation in live bacterial cells with potential applications in biotechnology and synthetic biology.
为了以动态方式对细胞进行编程，合成生物学家需要对基因表达的阈值水平和时间进行精确控制。然而，在实践中，基因表达的调控广泛使用典型的配体诱导型启动子，其可调性和时空分辨率有限。在此，我们构建了两个双输入混合启动子，每个启动子都保留了配体诱导型启动子的功能，同时通过一个蓝光可切换的调节旋钮进行了增强。使用新的启动子，我们表明配体和光输入都可以同步调节以实现所需的幅度，或者独立调节以在特定幅度下产生所需的频率。我们利用这两个启动子的多功能可编程性和正交性，构建了第一个可重新编程的逻辑基因电路，该电路能够在空间和时间上即时重新配置为逻辑或和N-蕴含逻辑，而无需修改电路。总体而言，我们展示了活细菌细胞中基于浓度和时间的组合调控，在生物技术和合成生物学中具有潜在应用。
