Bäcker Leonard E, Broux Kevin, Weckx Louise, Khanal Sadhana, Aertsen Abram
Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, KU Leuven, Kasteelpark Arenberg 23-bus 2457, 3001 Leuven, Belgium.
Nucleic Acids Res. 2025 Jan 7;53(1). doi: 10.1093/nar/gkae1158.
In order to increase our command over genetically engineered bacterial populations in bioprocessing and therapy, synthetic regulatory circuitry needs to enable the temporal programming of a number of consecutive functional tasks without external interventions. In this context, we have engineered a genetic circuit encoding an autonomous but chemically tunable timer in Escherichia coli, based on the concept of a transcription factor cascade mediated by the cytoplasmic dilution of repressors. As proof-of-concept, we used this circuit to impose a time-resolved two-staged synthetic pathway composed of a production-followed-by-lysis program, via a single input. Moreover, via a recombinase step, this synchronous timer was further engineered into an asynchronous timer in which the generational distance of differentiating daughter cells spawning off from a stem-cell like mother cell becomes a predictable driver and proxy for timer dynamics. Using this asynchronous timer circuit, a temporally defined population heterogeneity can be programmed in bacterial populations.
为了在生物加工和治疗中增强我们对基因工程细菌群体的控制能力，合成调控电路需要在无需外部干预的情况下，实现对一系列连续功能任务的时间编程。在此背景下，我们基于由阻遏物的细胞质稀释介导的转录因子级联概念，在大肠杆菌中设计了一种编码自主但化学可调定时器的遗传电路。作为概念验证，我们使用该电路通过单一输入施加了一个由生产后裂解程序组成的时间分辨两阶段合成途径。此外，通过重组酶步骤，这个同步定时器被进一步设计成一个异步定时器，其中从干细胞样母细胞分化出的子细胞的世代间隔成为定时器动态变化的可预测驱动因素和代理。利用这个异步定时器电路，可以在细菌群体中对时间定义的群体异质性进行编程。
