Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235.
Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235.
Proc Natl Acad Sci U S A. 2024 May 21;121(21):e2318690121. doi: 10.1073/pnas.2318690121. Epub 2024 May 13.
Cyanobacteria are photosynthetic bacteria whose gene expression patterns are globally regulated by their circadian (daily) clocks. Due to their ability to use sunlight as their energy source, they are also attractive hosts for "green" production of pharmaceuticals, renewable fuels, and chemicals. However, despite the application of traditional genetic tools such as the identification of strong promoters to enhance the expression of heterologous genes, cyanobacteria have lagged behind other microorganisms such as and yeast as economically efficient cell factories. The previous approaches have ignored large-scale constraints within cyanobacterial metabolic networks on transcription, predominantly the pervasive control of gene expression by the circadian (daily) clock. Here, we show that reprogramming gene expression by releasing circadian repressor elements in the transcriptional regulatory pathways coupled with inactivation of the central oscillating mechanism enables a dramatic enhancement of expression in cyanobacteria of heterologous genes encoding both catalytically active enzymes and polypeptides of biomedical significance.
蓝藻是光合细菌，其基因表达模式受其生物钟（每日）的全球调控。由于它们能够利用阳光作为能源，因此它们也是“绿色”生产药物、可再生燃料和化学品的有吸引力的宿主。然而，尽管应用了传统的遗传工具，如鉴定强启动子来增强异源基因的表达，但蓝藻在经济高效的细胞工厂方面落后于其他微生物，如 和酵母。以前的方法忽略了蓝藻代谢网络中对转录的大规模限制，主要是生物钟（每日）时钟对基因表达的普遍控制。在这里，我们表明，通过在转录调控途径中释放生物钟抑制剂元件并使中央振荡机制失活来重新编程基因表达，可以显著增强编码催化活性酶和具有生物医学意义的多肽的异源基因在蓝藻中的表达。
