title: An E3 ubiquitin ligase from Brassica napus induces a typical heat-shock response in its own way in Escherichia coli.
abstract: Previously, we have identified a novel E3 ubiquitin ligase, BNTR1, which plays a key role in heat stress response in Brassica napus. In this study, we accidentally found that BNTR1 can also improve thermal tolerance and reduce growth inhibition at 42°C in Escherichia coli, in a manner different from that in plant. We show that BNTR1 activates E. coli heat-shock response at low concentration in soluble form instead of in inclusion body, but BNTR1 is not functioning as a heat-shock protein (HSP) because deficient temperature-sensitive mutants of HSP genes display unconspicuous thermal tolerance in the presence of BNTR1. Our further studies show that BNTR1 triggers heat-shock response by competing with σ32 (σ32, heat-shock transcription factor) to its binding proteins DnaJ (HSP40) and DnaK (HSP70), which results in the release and accumulation of σ32, thereby promoting the heat-shock response, even under the non-heat-shock conditions. At 37°C, accumulation of the HSPs induced by BNTR1 could make cells much more tolerant than those without BNTR1 at 42°C. Thus, our results suggest that BNTR1 may potentially be a promising target in fermentation industry for reducing impact from temperature fluctuation, where E. coli works as bioreactors.
authors.affiliation: Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Huang
authors.affiliation: Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Niu
authors.affiliation: Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Liu
authors.affiliation: CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Weifeng
authors.initials: W
authors.lastname: Liu
authors.affiliation: Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China.
authors.forename: Xufeng
authors.initials: X
authors.lastname: Li
authors.affiliation: Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610064, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Tan
authors.affiliation: Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D029688:Brassica napus / Q000201:enzymology* / Q000235:genetics; D003593:Cytoplasm / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D050956:HSP40 Heat-Shock Proteins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism*; D018869:Heat-Shock Response / Q000235:genetics; D008856:Microscopy, Fluorescence; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014170:Transformation, Genetic; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: C494635:DnaJ protein, E coli; D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D044767:Ubiquitin-Protein Ligases; C063842:dnaK protein, E coli
keywords: E3 ubiquitin ligase; heat-shock response; thermal resistance; σ32