A temperature-inducible Targetron system for efficient gene inactivation in Escherichia coli.

Xingxing Zhao; Yumei Cheng; Changxue WU; Wei Ren; Fengqin Rao; Qian Zhou; Guzhen Cui; Xiaolan QI; Wei Hong

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A temperature-inducible Targetron system for efficient gene inactivation in Escherichia coli.

Author: Xingxing ZHAO ¹ ; Yumei CHENG ² ; Changxue WU ¹ ; Wei REN ³ ; Fengqin RAO ¹ ; Qian ZHOU ¹ ; Guzhen CUI ⁴ ; Xiaolan QI ¹ ; Wei HONG ¹
Author Information

1. Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang 550004, Guizhou, China.
2. Department of ICU, The Affiliate Hospital of Guizhou Medical University, Guiyang 550004, Guizhou, China.
3. Department of Immunology, Guizhou Medical University, Guiyang 550004, Guizhou, China.
4. Department of Microbiology, Guizhou Medical University, Guiyang 550025, Guizhou, China.
Publication Type:Journal Article
Keywords: Escherichia coli; Thermotargetron; dctA; fliC; gene inactivation; group Ⅱ intorn; temperature induciable
From: Chinese Journal of Biotechnology 2020;36(8):1659-1671
CountryChina
Language:Chinese
Abstract: To construct TeI3c/4c-based and temperature-inducible gene inactivation system (Thermotargetron) and to apply it to gene inactivation of mesophilic bacteria. The subunit of flagellum (fliC) and C4 dicarboxylate orotate:H⁺ symporter (dctA) genes were chosen as targets in the genome of Escherichia coli HMS174 (DE3) strain. According to recognition roles of TeI3c/4c intron, the fliC489a, fliC828s, fliC1038s and dctA2a sites were chosen as target sites. Gene-targeting plasmids were constructed based on pHK-TT1A by using overlap PCR method and transformed into HMS174 cells. An aliquot mid-log phase cultures of the transformants were shocked at 48 °C and plated on LB plate (containing chloramphenicol). Afterwards, gene mutants were screened by using colony PCR and DNA sequencing. After the mutants were obtained, the phenotypes of ΔfliC and ΔdctA gene mutants were characterized by using agar puncture and carbon metabolism experiments. Colony PCR and sequencing results show that TeI3c/4c intron was inserted in the designed sites of fliC and dctA genes. The gene-targeting efficiency of Thermotargetron system was 100%. Phenotype verification experiments of the mutants demonstrated that the cell motility of all ΔfliC mutants was damaged and the malate assimilation ability of ΔdctA mutant was deprived comparing to wild-type HMS174 strain. In our study, a temperature-inducible and high-efficiency gene inactivation system was established for mesophilic bacteria. This system could achieve high efficiency and precise gene inactivation by modulation of the incubation duration of the transformants at 48 °C.