Li Zhen, Liu Jian-Zhong
Institute of Synthetic Biology, Biomedical Center, Guangdong Provincial Key Laboratory of Improved Variety Reproduction in Aquatic Economic Animals and South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
Front Microbiol. 2017 Oct 17;8:1987. doi: 10.3389/fmicb.2017.01987. eCollection 2017.
Putrescine is widely used in industrial production of bioplastics, pharmaceuticals, agrochemicals, and surfactants. Although engineered has been successfully used to produce high levels of putrescine, the overall cellular physiological and metabolic changes caused by overproduction of putrescine remains unclear. To reveal the transcriptional changes that occur in response to putrescine production in an engineered strain, a comparative transcriptomic analysis was carried out. Overproduction of putrescine resulted in transcriptional downregulation of genes involved in glycolysis; the TCA cycle, pyruvate degradation, biosynthesis of some amino acids, oxidative phosphorylation; vitamin biosynthesis (thiamine and vitamin 6), metabolism of purine, pyrimidine and sulfur, and ATP-, NAD-, and NADPH-consuming enzymes. The transcriptional levels of genes involved in ornithine biosynthesis and NADPH-forming related enzymes were significantly upregulated in the putrescine producing strain PUT-ALE. Comparative transcriptomic analysis provided some genetic modification strategies to further improve putrescine production. Repressing ATP- and NADPH-consuming enzyme coding gene expression via CRISPRi enhanced putrescine production.
腐胺广泛应用于生物塑料、药品、农用化学品和表面活性剂的工业生产中。尽管工程菌已成功用于高产腐胺，但腐胺过量生产引起的整体细胞生理和代谢变化仍不清楚。为了揭示工程菌中腐胺生产所引发的转录变化，进行了一项比较转录组分析。腐胺的过量生产导致参与糖酵解、三羧酸循环、丙酮酸降解、某些氨基酸生物合成、氧化磷酸化、维生素生物合成（硫胺素和维生素B6）、嘌呤、嘧啶和硫代谢以及消耗ATP、NAD和NADPH的酶的基因转录下调。在产腐胺的工程菌PUT-ALE中，参与鸟氨酸生物合成和形成NADPH相关酶的基因转录水平显著上调。比较转录组分析提供了一些基因改造策略以进一步提高腐胺产量。通过CRISPRi抑制消耗ATP和NADPH的酶编码基因的表达可提高腐胺产量。
