Development of an autonomous and bifunctional quorum-sensing circuit for metabolic flux control in engineered Escherichia coli
Development of an autonomous and bifunctional quorum-sensing circuit for metabolic flux control in engineered Escherichia coli
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DOI：
10.1073/pnas.1911144116
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发表时间：
2019-12-17
影响因子：
11.1
通讯作者：
Prather, Kristala L. J.
中科院分区：
文献类型：
--
作者：
Dinh, Christina V.;Prather, Kristala L. J.
代谢工程旨在重新编程微生物细胞，以有效和可持续地生产增值化合物。由于化学物质的产生可能与细胞的自然目标不一致，因此已经开发了平衡冲突目标的策略。例如，动态调节调节基因表达，以有利于在低细胞密度下的生物量和代谢物积累，然后将关键代谢通量转向产物形成。为了在不需要外源诱导剂的情况下以途径独立的方式触发基因表达的变化，研究人员将基因表达与群体感应（QS）电路相结合，该电路基于细胞密度调节转录。虽然有效，但迄今为止的研究仅限于一个控制点。更具挑战性的途径可能需要分层的动态调控策略，从而促进了用于调控多组基因的可推广工具的开发。我们已经开发了一种基于QS的调控工具，该工具结合了lux和esa QS系统的组件，以同时动态地上调和下调2组基因的表达。电路的表征表明，改变2个QS组分的表达水平导致开关动态的可预测变化，并且使用来自2个QS系统的组分允许独立调谐能力。我们应用调控工具成功地解决了柚皮素和水杨酸合成途径中的挑战。通过这些案例研究，我们确认了具有多个控制点、可预测的调节能力和独立可调的调节模块的好处。
Metabolic engineering seeks to reprogram microbial cells to efficiently and sustainably produce value-added compounds. Since chemical production can be at odds with the cell's natural objectives, strategies have been developed to balance conflicting goals. For example, dynamic regulation modulates gene expression to favor biomass and metabolite accumulation at low cell densities before diverting key metabolic fluxes toward product formation. To trigger changes in gene expression in a pathway-independent manner without the need for exogenous inducers, researchers have coupled gene expression to quorum-sensing (QS) circuits, which regulate transcription based on cell density. While effective, studies thus far have been limited to one control point. More challenging pathways may require layered dynamic regulation strategies, motivating the development of a generalizable tool for regulating multiple sets of genes. We have developed a QS-based regulation tool that combines components of the lux and esa QS systems to simultaneously and dynamically up- and down-regulate expression of 2 sets of genes. Characterization of the circuit revealed that varying the expression level of 2 QS components leads to predictable changes in switching dynamics and that using components from 2 QS systems allows for independent tuning capability. We applied the regulation tool to successfully address challenges in both the naringenin and salicylic acid synthesis pathways. Through these case studies, we confirmed the benefit of having multiple control points, predictable tuning capabilities, and independently tunable regulation modules.