Significant Rewiring of the Transcriptome and Proteome of an Escherichia coli Strain Harboring a Tailored Exogenous Global Regulator IrrE

Tingjian Chen,Zhanglin Lin,Lingli Zeng,Jianqing Wang,Yilu Chen,Jicong Li,Rizong Li,Mark Isalan

doi:10.1371/journal.pone.0037126

Tingjian Chen, Zhanglin Lin + Show 6 more

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https://doi.org/10.1371/journal.pone.0037126

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Journal: PLoS ONE	Publication Date: Jul 5, 2012
Citations: 81	License type: CC BY 4.0

Affiliation: Tsinghua University, Nanjing Tech University

Abstract

Cell reprogramming for microorganisms via engineered or artificial transcription factors and RNA polymerase mutants has presented a powerful tool for eliciting complex traits that are practically useful particularly for industrial strains, and for understanding at the global level the regulatory network of gene transcription. We previously further showed that an exogenous global regulator IrrE (derived from the extreme radiation-resistant bacterium Deinococcus radiodurans) can be tailored to confer Escherichia coli (E. coli) with significantly enhanced tolerances to different stresses. In this work, based on comparative transcriptomic and proteomic analyses of the representative strains E1 and E0, harboring the ethanol-tolerant IrrE mutant E1 and the ethanol-intolerant wild type IrrE, respectively, we found that the transcriptome and proteome of E. coli were extensively rewired by the tailored IrrE protein. Overall, 1196 genes (or approximately 27% of E. coli genes) were significantly altered at the transcriptomic level, including notably genes in the nitrate-nitrite-nitric oxide (NO) pathway, and genes for non-coding RNAs. The proteomic profile revealed significant up- or downregulation of several proteins associated with syntheses of the cell membrane and cell wall. Analyses of the intracellular NO level and cell growth under reduced temperature supported a close correlation between NO and ethanol tolerance, and also suggests a role for membrane fluidity. The significantly different omic profiles of strain E1 indicate that IrrE functions as a global regulator in E. coli, and that IrrE may be evolved for other cellular tolerances. In this sense, it will provide synthetic biology with a practical and evolvable regulatory “part” that operates at a higher level of complexity than local regulators. This work also suggests a possibility of introducing and engineering other exogenous global regulators to rewire the genomes of microorganism cells.

Highlights

In recent years, it has been shown that the transcriptomes of microorganisms can be altered by artificial transcription factors, mutants of innate transcription factors and RNA polymerase, and an exogenous global regulator (IrrE) and its mutants, leading to significantly altered cellular phenotypes [1,2,3,4,5,6,7]
Transcriptome Profiles of the Strains E1 and E0 To directly analyze the alterations at the transcriptomic and proteomic levels in E. coli achieved by the engineered IrrE mutant E1 that confers ethanol tolerance while the wild type IrrE does not, we compared the global transcriptome and proteome between E. coli DH5a strains E1 and E0, harboring the irrE mutant E1 and the wild type irrE gene, respectively, under ethanol stress
We show that the transcriptomic and proteomic profiles of E. coli strain E1 harboring the ethanol-tolerant global regulator mutant E1 were significantly different from those of the starting strain E0 containing the wild type IrrE, which does not confer ethanol tolerance

Summary

Introduction

It has been shown that the transcriptomes of microorganisms can be altered by artificial transcription factors, mutants of innate transcription factors and RNA polymerase, and an exogenous global regulator (IrrE) and its mutants, leading to significantly altered cellular phenotypes [1,2,3,4,5,6,7]. This suggests a clearly complex but amendable regulatory network for a given genome.

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