Title Tn5 Transposon-based Mutagenesis for Engineering Phage-resistant Strains of Escherichia coli BL21 (DE3)
Author Yinfeng Wang, Guanhua Xuan, Houqi Ning, Jiuna Kong, Hong Lin, and Jingxue Wang*
Address Food Safety Laboratory, College of Food Science and Engineering, Ocean University of China, 266003 Qingdao, People’s Republic of China
Bibliography Journal of Microbiology, 61(5),559-569, 2023,
DOI 10.1007/s12275-023-00048-2
Key Words Escherichia coli BL21 (DE3) · Phage contamination · Tn5 · Phage-resistant strains
Abstract Escherichia coli is a preferred strain for recombinant protein production, however, it is often plagued by phage infection during experimental studies and industrial fermentation. While the existing methods of obtaining phage-resistant strains by natural mutation are not efficient enough and time-consuming. Herein, a high-throughput method by combining Tn5 transposon mutation and phage screening was used to produce Escherichia coli BL21 (DE3) phage-resistant strains. Mutant strains PR281-7, PR338-8, PR339-3, PR340-8, and PR347-9 were obtained, and they could effectively resist phage infection. Meanwhile, they had good growth ability, did not contain pseudolysogenic strains, and were controllable. The resultant phage-resistant strains maintained the capabilities of producing recombinant proteins since no difference in mCherry red fluorescent protein expression was found in phage-resistant strains. Comparative genomics showed that PR281-7, PR338-8, PR339-3, and PR340-8 mutated in ecpE, nohD, nrdR, and livM genes, respectively. In this work, a strategy was successfully developed to obtain phage-resistant strains with excellent protein expression characteristics by Tn5 transposon mutation. This study provides a new reference to solve the phage contamination problem.