Lu Yudan, Zheng Xiaomei, Wang Yu, Zhang Lihui, Wang Lixian, Lei Yu, Zhang Tongcun, Zheng Ping, Sun Jibin
College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China.
Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
J Fungi (Basel). 2022 May 26;8(6):568. doi: 10.3390/jof8060568.
is an important industrial workhorse for the biomanufacturing of organic acids, proteins, etc. Well-controlled genetic regulatory elements, including promoters, are vital for strain engineering, but available strong promoters for are limited. Herein, to efficiently assess promoters, we developed an accurate and intuitive fluorescent-auxotrophic selection workflow based on , , CRISPR/Cas9 system, and flow cytometry. With this workflow, we characterized six endogenous constitutive promoters in . The endogenous glyceraldehyde-3-phosphate dehydrogenase promoter P showed a 2.28-fold increase in promoter activity compared with the most frequently used strong promoter P from . Six predicted conserved motifs, including the -box, were verified to be essential for the P activity. To demonstrate its application, the promoter P was used for enhancing the expression of citrate exporter in a citric acid-producing isolate D353.8. Compared with the controlled by P, the transcription level of the gene driven by P increased by 2.19-fold, which is consistent with the promoter activity assessment. Moreover, following overexpression, several genes involved in carbohydrate transport and metabolism were synergically upregulated, resulting in up to a 2.48-fold increase in citric acid titer compared with that of the parent strain. This study provides an intuitive workflow to speed up the quantitative evaluation of promoters and strong constitutive promoters for fungal cell factory construction and strain engineering.
是有机酸、蛋白质等生物制造的重要工业主力。包括启动子在内的良好控制的基因调控元件对于菌株工程至关重要,但用于的可用强启动子有限。在此,为了有效评估启动子,我们基于、、CRISPR/Cas9系统和流式细胞术开发了一种准确且直观的荧光营养缺陷型选择工作流程。通过该工作流程,我们对中的六个内源性组成型启动子进行了表征。内源性甘油醛-3-磷酸脱氢酶启动子P与中最常用的强启动子P相比,启动子活性提高了2.28倍。包括-box在内的六个预测保守基序被证实对P活性至关重要。为了证明其应用,启动子P用于增强柠檬酸生产菌株D353.8中柠檬酸转运蛋白的表达。与由P控制的相比,由P驱动的基因的转录水平提高了2.19倍,这与启动子活性评估一致。此外,过表达后,几个参与碳水化合物运输和代谢的基因协同上调,与亲本菌株相比,柠檬酸产量提高了2.48倍。本研究提供了一种直观的工作流程,以加速对用于真菌细胞工厂构建和菌株工程的启动子和强组成型启动子的定量评估。