Transcriptomic changes of Escherichia coli expressing BnTR1 at normal and heat stress conditions

The heat shock response is critical for organisms to survive at a high temperature. Heterologous expression of eukaryotic molecular chaperons protects Escherichia coli against heat stress. Here we report that expression of the plant E3 ligase BnTR1 significantly increase the thermotolerance of Escherichia coli. Different from eukaryotic chaperones, BnTR1 post-transcriptionally regulates the heat shock factor σ32 though zinc fingers of the RING domain, which interacts with DnaK resulting in stabilizing σ32 and subsequently up-regulating heat shock proteins. Our findings indicate the expression of BnTR1 confers thermoprotective effects on E. coli cells, and it may provide useful clues to engineer thermophilic bacterial strains. E. coli cells transformed with pET-28a or pET-28a-BnTR1 (OD600nm = 0.6) were induced with 0.1 mM IPTG at 37°C for 1 hour. Then cells were transferred and incubated at 37°C and 42°C for 1 hour, respectively.