DNA Microarray of Global Transcription Factor Mutant Reveals Membrane-Related Proteins Involved in n-Butanol Tolerance in Escherichia coli

We successfully isolated an E. coli strain harboring rpoD mutant B8 with 2% (v/v) butanol tolerance using global transcriptional machinery engineering approach. DNA microarrays were employed to assess the transcriptome profile of n-butanol tolerance strain B8 and control strain E. coli JM109. The goal of this study is therefore to identify E. coli genes that are involved in n-butanol tolerance. E. coli strains harboring σ70 mutant B8 and WT were cultured overnight and inoculated (1%) into fresh medium. n-Butanol (0.8%, v/v) was added at 0.8 OD660 and further incubated for 1.5 h. Cells were harvested by centrifugation (5500 g, 4°C). Total RNA was extracted using Qiagen RNeasy kit (Hilden, Germany) following manufacturer’s instructions. Qualified total RNA was further purified by Qiagen RNeasy mini kit and RNase-Free DNase Set. Three biological replicates of RNA samples were used to further DNA microarrays analysis.