Impairment of Ribosome Maturation or Function Confers Salt Resistance on Escherichia coli Cells

Hase, Yoichi; Tarusawa, Takefusa; Muto, Akira; Himeno, Hyouta

doi:10.1371/journal.pone.0065747

Cited by 11 publications

(9 citation statements)

References 40 publications

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“…A range of SNPs in intergenic regions and the coding sequences of various other genes were also detected, including a synonymous substitution in treR, a negative regulator of trehalose biosynthesis, in G3 and the S6 ribosomal protein rpsA in G6. Other mutations of ribosomal proteins have been found to confer salt tolerance as well (40) by impairing ribosome maturation, but further investigation is needed to understand the functional consequences of this particular point mutation.…”

Section: Resultsmentioning

confidence: 99%

Evolved Osmotolerant Escherichia coli Mutants Frequently Exhibit Defective N -Acetylglucosamine Catabolism and Point Mutations in Cell Shape-Regulating Protein MreB

Winkler

Garcı́a

Olson

et al. 2014

Appl Environ Microbiol

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c Biocatalyst robustness toward stresses imposed during fermentation is important for efficient bio-based production. Osmotic stress, imposed by high osmolyte concentrations or dense populations, can significantly impact growth and productivity. In order to better understand the osmotic stress tolerance phenotype, we evolved sexual (capable of in situ DNA exchange) and asexual Escherichia coli strains under sodium chloride (NaCl) stress. All isolates had significantly improved growth under selection and could grow in up to 0.80 M (47 g/liter) NaCl, a concentration that completely inhibits the growth of the unevolved parental strains. Whole genome resequencing revealed frequent mutations in genes controlling N-acetylglucosamine catabolism (nagC, nagA), cell shape (mrdA, mreB), osmoprotectant uptake (proV), and motility (fimA). Possible epistatic interactions between nagC, nagA, fimA, and proV deletions were also detected when reconstructed as defined mutations. Biofilm formation under osmotic stress was found to be decreased in most mutant isolates, coupled with perturbations in indole secretion. Transcriptional analysis also revealed significant changes in ompACGL porin expression and increased transcription of sulfonate uptake systems in the evolved mutants. These findings expand our current knowledge of the osmotic stress phenotype and will be useful for the rational engineering of osmotic tolerance into industrial strains in the future. Escherichia coli, an important industrial microorganism for the production of a wide variety of fine chemicals, fuels, and proteins, has been extensively targeted to improve its suitability as a biofactory. Strain development efforts have focused on improving tolerance of feedstocks containing toxic compounds (1, 2) or products (3, 4). Many environmental variables, including osmotic pressure, can negatively impact biocatalyst performance (5). Use of nonconventional waste streams, such as waste glycerol or brackish water sources, to support microbial growth can also reduce process costs (6, 7) while reducing pressure on fresh water resources; however, these carbon and water sources generally contain high concentrations of salt that may be inhibitory to microbial growth. In addition to osmotic stresses, excess Na ϩ can disrupt the ion homeostasis in E. coli as well (8). Previous studies have attempted to engineer improved osmotic tolerance in E. coli (9, 10), but overall, knowledge of the genetic mechanisms that confer tolerance of osmotic stress in general or to specific osmolytes remains limited. A detailed analysis of E. coli osmotolerance to osmolytes would therefore provide new insight into the molecular mechanisms underlying this complex phenotype.Adaptive laboratory evolution (11) is a promising approach to identify potentially novel osmotic tolerance mechanisms, as this technique requires no assumptions about the underlying genotype-phenotype relationship. Complex phenotypes, such as enhanced resistance to biofuels (3,4,12), lignocellulosic hydrolysates (2, 13), antibiot...

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Section: Resultsmentioning

confidence: 99%

Evolved Osmotolerant Escherichia coli Mutants Frequently Exhibit Defective N -Acetylglucosamine Catabolism and Point Mutations in Cell Shape-Regulating Protein MreB

Winkler

Garcı́a

Olson

et al. 2014

Appl Environ Microbiol

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“…In other words, the salt in the in vitro experiments partially compensates the functional role of assembly factors, by preventing the formation of kinetic traps. Indeed, a very interesting observation is that deletion of assembly factor genes confers salt resistance to E. coli cells (Hase et al, 2013 ; Hase et al, 2009 ), which also seems to suggest an equivalency between assembly factors and the salt ions.…”

Section: Discussionmentioning

confidence: 99%

Structural insights into the assembly of the 30S ribosomal subunit in vivo: functional role of S5 and location of the 17S rRNA precursor sequence

Yang¹,

Guo²,

Goto³

et al. 2014

Protein Cell

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The in vivo assembly of ribosomal subunits is a highly complex process, with a tight coordination between protein assembly and rRNA maturation events, such as folding and processing of rRNA precursors, as well as modifications of selected bases. In the cell, a large number of factors are required to ensure the efficiency and fidelity of subunit production. Here we characterize the immature 30S subunits accumulated in a factor-null Escherichia coli strain (∆rsgA∆rbfA). The immature 30S subunits isolated with varying salt concentrations in the buffer system show interesting differences on both protein composition and structure. Specifically, intermediates derived under the two contrasting salt conditions (high and low) likely reflect two distinctive assembly stages, the relatively early and late stages of the 3′ domain assembly, respectively. Detailed structural analysis demonstrates a mechanistic coupling between the maturation of the 5′ end of the 17S rRNA and the assembly of the 30S head domain, and attributes a unique role of S5 in coordinating these two events. Furthermore, our structural results likely reveal the location of the unprocessed terminal sequences of the 17S rRNA, and suggest that the maturation events of the 17S rRNA could be employed as quality control mechanisms on subunit production and protein translation.Electronic supplementary materialThe online version of this article (doi:10.1007/s13238-014-0044-1) contains supplementary material, which is available to authorized users.

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“…It should also be noted that under stress conditions, dissociation of ribosomes into its subunits occurs (i) when cells are subjected to a high salt concentration (Hase et al . ) or (ii) precedes ribosome degradation during carbon starvation (Zundel et al . ).…”

Section: Introductionmentioning

confidence: 99%

“…During translation, in the post-termination stage, the 70S ribosomes are dissociated into stable subunits by cooperative action of three translation factors: ribosome recycling factor (RRF), elongation factor G (EF-G) and initiation factor 3 (IF3), a step necessary for sustenance of translation initiation (Hirokawa et al 2005). It should also be noted that under stress conditions, dissociation of ribosomes into its subunits occurs (i) when cells are subjected to a high salt concentration (Hase et al 2013) or (ii) precedes ribosome degradation during carbon starvation (Zundel et al 2009). Since the peptidyl transferase centre (PTC) located on the domain V of 23S rRNA of the large ribosomal subunit is the site of interaction of the unfolded protein during ribosomeassisted protein folding, we investigated the effect of PTC-binding antibiotics chloramphenicol and blasticidin (Polacek and Mankin 2005) on the unfolded protein and factor-mediated ribosome subunit dissociation.…”

Section: Introductionmentioning

confidence: 99%

Inhibition of Escherichia coli ribosome subunit dissociation by chloramphenicol and Blasticidin: a new mode of action of the antibiotics

Pathak

Mondal

Barat

2016

Lett Appl Microbiol

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Ribosome synthesizes protein in all organisms and is the target for multiple antimicrobial agents. Our study demonstrates that chloramphenicol and blasticidin S that target the peptidyl transferase centre of the bacterial ribosome can then inhibit dissociation of 70S ribosome mediated by (i) unfolded protein, (ii) translation factors or (iii) low Mg concentrations in vitro and thereby suppresses ribosomal degradation during carbon starvation in vivo. The demonstration of this new mode of action furthers the understanding of these broad-spectrum antibiotics that differentially inhibit protein synthesis in prokaryotic and eukaryotic cells.

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Impairment of Ribosome Maturation or Function Confers Salt Resistance on Escherichia coli Cells

Cited by 11 publications

References 40 publications

Evolved Osmotolerant Escherichia coli Mutants Frequently Exhibit Defective N -Acetylglucosamine Catabolism and Point Mutations in Cell Shape-Regulating Protein MreB

Evolved Osmotolerant Escherichia coli Mutants Frequently Exhibit Defective N -Acetylglucosamine Catabolism and Point Mutations in Cell Shape-Regulating Protein MreB

Structural insights into the assembly of the 30S ribosomal subunit in vivo: functional role of S5 and location of the 17S rRNA precursor sequence

Inhibition of Escherichia coli ribosome subunit dissociation by chloramphenicol and Blasticidin: a new mode of action of the antibiotics

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