Overexpression of Cloned
            <i>RhsA</i>
            Sequences Perturbs the Cellular Translational Machinery in Escherichia coli

Aggarwal, Kunal; Lee, Kelvin H.

doi:10.1128/jb.05061-11

Cited by 13 publications

(8 citation statements)

References 18 publications

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“…Early studies found that the E. coli rhsA core extension inhibits recovery from stationary phase (17), and recent work suggests that this toxin inhibits protein synthesis (18). Additionally, a plasmid-encoded Rhs protein has been implicated in bacteriocin production in Pseudomonas savastanoi (19).…”

Section: Discussionmentioning

confidence: 99%

Rhs proteins from diverse bacteria mediate intercellular competition

Koskiniemi¹,

Lamoureux²,

Nikolakakis³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

367

437

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Rearrangement hotspot (Rhs) and related YD-peptide repeat proteins are widely distributed in bacteria and eukaryotes, but their functions are poorly understood. Here, we show that Gram-negative Rhs proteins and the distantly related wall-associated protein A (WapA) from Gram-positive bacteria mediate intercellular competition. Rhs and WapA carry polymorphic C-terminal toxin domains (Rhs-CT/WapA-CT), which are deployed to inhibit the growth of neighboring cells. These systems also encode sequence-diverse immunity proteins (RhsI/WapI) that specifically neutralize cognate toxins to protect rhs + /wapA + cells from autoinhibition. RhsA and RhsB from Dickeya dadantii 3937 carry nuclease domains that degrade target cell DNA. D. dadantii 3937 rhs genes do not encode secretion signal sequences but are linked to hemolysin-coregulated protein and valine-glycine repeat protein G genes from type VI secretion systems. Valine-glycine repeat protein G is required for inhibitor cell function, suggesting that Rhs may be exported from D. dadantii 3937 through a type VI secretion mechanism. In contrast, WapA proteins from Bacillus subtilis strains appear to be exported through the general secretory pathway and deliver a variety of tRNase toxins into neighboring target cells. These findings demonstrate that YD-repeat proteins from phylogenetically diverse bacteria share a common function in contact-dependent growth inhibition.

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Section: Discussionmentioning

confidence: 99%

Rhs proteins from diverse bacteria mediate intercellular competition

Koskiniemi¹,

Lamoureux²,

Nikolakakis³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

367

437

View full text Add to dashboard Cite

show abstract

“…There is also an rhsA gene and 3 rhs-like elements. RhsA, a nuclease, has been shown to affect the expression of genes involved in transcription, RNA processing, nucleotide biosynthesis and metabolism, and amino acid biosynthesis in E. coli (37). rhsA is also embedded in the T6SS gene cluster in Dickeya dadantii and is likely to be exported through the T6SS (38).…”

Section: Discussionmentioning

confidence: 99%

The Type VI Secretion System Modulates Flagellar Gene Expression and Secretion in Citrobacter freundii and Contributes to Adhesion and Cytotoxicity to Host Cells

et al. 2015

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eThe type VI secretion system (T6SS) as a virulence factor-releasing system contributes to virulence development of various pathogens and is often activated upon contact with target cells. Citrobacter freundii strain CF74 has a complete T6SS genomic island (GI) that contains clpV, hcp-2, and vgr T6SS genes. We constructed clpV, hcp-2, vgr, and T6SS GI deletion mutants in CF74 and analyzed their effects on the transcriptome overall and, specifically, on the flagellar system at the levels of transcription and translation. Deletion of the T6SS GI affected the transcription of 84 genes, with 15 and 69 genes exhibiting higher and lower levels of transcription, respectively. Members of the cell motility class of downregulated genes of the CF74⌬T6SS mutant were mainly flagellar genes, including effector proteins, chaperones, and regulators. Moreover, the production and secretion of FliC were also decreased in clpV, hcp-2, vgr, or T6SS GI deletion mutants in CF74 and were restored upon complementation. In swimming motility assays, the mutant strains were found to be less motile than the wild type, and motility was restored by complementation. The mutant strains were defective in adhesion to HEp-2 cells and were restored partially upon complementation. Further, the CF74⌬T6SS, CF74⌬clpV, and CF74⌬hcp-2 mutants induced lower cytotoxicity to HEp-2 cells than the wild type. These results suggested that the T6SS GI in CF74 regulates the flagellar system, enhances motility, is involved in adherence to host cells, and induces cytotoxicity to host cells. Thus, the T6SS plays a wide-ranging role in C. freundii.

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“…This effect could be impeded by the coexpression of a downstream gene (Vlazny & Hill, 1995), apparently functioning as an antitoxin module. Subsequently, Aggarwal and Lee demonstrated that the RhsA function interferes with transcription and translation, though the exact mechanism of its action remains unknown (Aggarwal & Lee, 2011). In P. savastanoi pv.…”

Section: Inhibitory Activities Of Rhs Systemsmentioning

confidence: 99%

Ribosomally encoded antibacterial proteins and peptides fromPseudomonas

2014

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Members of the Pseudomonas genus produce diverse secondary metabolites affecting other bacteria, fungi or predating nematodes and protozoa but are also equipped with the capacity to secrete different types of ribosomally encoded toxic peptides and proteins, ranging from small microcins to large tailocins. Studies with the human pathogen Pseudomonas aeruginosa have revealed that effector proteins of type VI secretion systems are part of the antibacterial armamentarium deployed by pseudomonads. A novel class of antibacterial proteins with structural similarity to plant lectins was discovered by studying antagonism among plant-associated Pseudomonas strains. A genomic perspective on pseudomonad bacteriocinogeny shows that the modular architecture of S pyocins of P. aeruginosa is retained in a large diversified group of bacteriocins, most of which target DNA or RNA. Similar modularity is present in as yet poorly characterized Rhs (recombination hot spot) proteins and CDI (contact-dependent inhibition) proteins. Well-delimited domains for receptor recognition or cytotoxicity enable the design of chimeric toxins with novel functionalities, which has been applied successfully for S and R pyocins. Little is known regarding how these antibacterials are released and ultimately reach their targets. Other remaining issues concern the identification of environmental triggers activating these systems and assessment of their ecological impact in niches populated by pseudomonads.

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Overexpression of Cloned RhsA Sequences Perturbs the Cellular Translational Machinery in Escherichia coli

Cited by 13 publications

References 18 publications

Rhs proteins from diverse bacteria mediate intercellular competition

Rhs proteins from diverse bacteria mediate intercellular competition

The Type VI Secretion System Modulates Flagellar Gene Expression and Secretion in Citrobacter freundii and Contributes to Adhesion and Cytotoxicity to Host Cells

Ribosomally encoded antibacterial proteins and peptides fromPseudomonas

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