title: Engineering Synthetic Multistress Tolerance in Escherichia coli by Using a Deinococcal Response Regulator, DR1558.
abstract: Cellular robustness is an important trait for industrial microbes, because the microbial strains are exposed to a multitude of different stresses during industrial processes, such as fermentation. Thus, engineering robustness in an organism in order to push the strains toward maximizing yield has become a significant topic of research. We introduced the deinococcal response regulator DR1558 into Escherichia coli (strain Ec-1558), thereby conferring tolerance to hydrogen peroxide (H2O2). The reactive oxygen species (ROS) level in strain Ec-1558 was reduced due to the increased KatE catalase activity. Among four regulators of the oxidative-stress response, OxyR, RpoS, SoxS, and Fur, we found that the expression of rpoS increased in Ec-1558, and we confirmed this increase by Western blot analysis. Electrophoretic mobility shift assays showed that DR1558 bound to the rpoS promoter. Because the alternative sigma factor RpoS regulates various stress resistance-related genes, we performed stress survival analysis using an rpoS mutant strain. Ec-1558 was able to tolerate a low pH, a high temperature, and high NaCl concentrations in addition to H2O2, and the multistress tolerance phenotype disappeared in the absence of rpoS. Microarray analysis clearly showed that a variety of stress-responsive genes that are directly or indirectly controlled by RpoS were upregulated in strain Ec-1558. These findings, taken together, indicate that the multistress tolerance conferred by DR1558 is likely routed through RpoS. In the present study, we propose a novel strategy of employing an exogenous response regulator from polyextremophiles for strain improvement.
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea.
authors.forename: Deepti
authors.initials: D
authors.lastname: Appukuttan
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea.
authors.forename: Harinder
authors.initials: H
authors.lastname: Singh
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea.
authors.forename: Sun-Ha
authors.initials: SH
authors.lastname: Park
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea.
authors.forename: Jong-Hyun
authors.initials: JH
authors.lastname: Jung
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea.
authors.forename: Sunwook
authors.initials: S
authors.lastname: Jeong
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea.
authors.forename: Ho Seong
authors.initials: HS
authors.lastname: Seo
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea.
authors.forename: Yong Jun
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea saylim@kaeri.re.kr.
authors.forename: Sangyong
authors.initials: S
authors.lastname: Lim
mesh_terms: D034301:Deinococcus / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005818:Genetic Engineering; D006861:Hydrogen Peroxide / Q000378:metabolism*; D018384:Oxidative Stress; D013312:Stress, Physiological
chemical_list: D029968:Escherichia coli Proteins; D006861:Hydrogen Peroxide