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Genetic manipulations restored the growth fitness of reduced-genome Escherichia coli

Paper ID Volume ID Publish Year Pages File Format Full-Text
20850 43194 2013 7 PDF Available
Title
Genetic manipulations restored the growth fitness of reduced-genome Escherichia coli
Abstract

Microbes with smaller genomes would be better chassis for analysis, design, and improvement in the fields of metabolic engineering, synthetic biology, and molecular breeding. To create an Escherichia coli strain with a smaller genome, we used a stepwise genome reduction approach. Beginning with strain MGF-01, which has a genome of 3.62 megabase pairs (Mbp), we generated two E. coli K-12 strains without any insertion sequence (IS), DGF-327 and DGF-298, with reduced genome sizes of 3.27 and 2.98 Mbp, respectively. During the strain construction, intrinsic mutations of ilvG and rph were functionally restored to accelerate initial growth after inoculation. The genomes of the two strains were sequenced, and their structures were confirmed. Both strains showed no auxotrophy, and had better growth fitness, especially in the initial phase, and better cell yield in a rich medium than the wild type K-12 strain. Transcriptome analysis revealed that ibpAB and lon, which encode a heat-shock chaperone and a protease for abnormal proteins, respectively, are down-regulated in DGF strains, compared to the ancestral strains with larger genomes. We concluded that down-regulation of the genes encoding chaperones and proteases is one of the factors that improve the fitness of DGF strains. The DGF strains with fewer genes and better cell yield will be good hosts for applications.

Keywords
Escherichia coli; Genome reduction; Metabolic engineering; Synthetic biology; Molecular breeding
First Page Preview
Genetic manipulations restored the growth fitness of reduced-genome Escherichia coli
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 116, Issue 1, July 2013, Pages 52–58
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering