Coupling between the Basic Replicon and the Kis-Kid Maintenance System of Plasmid R1: Modulation by  Kis Antitoxin Levels and Involvement in Control of  Plasmid Replication

López-Villarejo, Juan; Lobato‐Márquez, Damián; Dı́az-Orejas, Ramón

doi:10.3390/toxins7020478

Cited by 10 publications

(9 citation statements)

References 38 publications

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“…Mean data were taken as the relative expression levels of the proteins. Band densitometry was determined using Quantity One v.4.6.3 software (Bio-Rad, Berkeley, CA) as previously described (Molina-García and Giraldo, 2014 ; López-Villarejo et al, 2015 ).…”

Section: Methodsmentioning

confidence: 99%

Stabilization of the Virulence Plasmid pSLT of Salmonella Typhimurium by Three Maintenance Systems and Its Evaluation by Using a New Stability Test

Lobato‐Márquez

García

Moreno-Córdoba

et al. 2016

Front. Mol. Biosci.

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Certain Salmonella enterica serovars belonging to subspecies I carry low-copy-number virulence plasmids of variable size (50–90 kb). All of these plasmids share the spv operon, which is important for systemic infection. Virulence plasmids are present at low copy numbers. Few copies reduce metabolic burden but suppose a risk of plasmid loss during bacterial division. This drawback is counterbalanced by maintenance modules that ensure plasmid stability, including partition systems and toxin-antitoxin (TA) loci. The low-copy number virulence pSLT plasmid of Salmonella enterica serovar Typhimurium encodes three auxiliary maintenance systems: one partition system (parAB) and two TA systems (ccdABST and vapBC2ST). The TA module ccdABST has previously been shown to contribute to pSLT plasmid stability and vapBC2ST to bacterial virulence. Here we describe a novel assay to measure plasmid stability based on the selection of plasmid-free cells following elimination of plasmid-containing cells by ParE toxin, a DNA gyrase inhibitor. Using this new maintenance assay we confirmed a crucial role of parAB in pSLT maintenance. We also showed that vapBC2ST, in addition to contribute to bacterial virulence, is important for plasmid stability. We have previously shown that ccdABST encodes an inactive CcdBST toxin. Using our new stability assay we monitored the contribution to plasmid stability of a ccdABST variant containing a single mutation (R99W) that restores the toxicity of CcdBST. The “activation” of CcdBST (R99W) did not increase pSLT stability by ccdABST. In contrast, ccdABST behaves as a canonical type II TA system in terms of transcriptional regulation. Of interest, ccdABST was shown to control the expression of a polycistronic operon in the pSLT plasmid. Collectively, these results show that the contribution of the CcdBST toxin to pSLT plasmid stability may depend on its role as a co-repressor in coordination with CcdAST antitoxin more than on its toxic activity.

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Section: Methodsmentioning

confidence: 99%

Stabilization of the Virulence Plasmid pSLT of Salmonella Typhimurium by Three Maintenance Systems and Its Evaluation by Using a New Stability Test

Lobato‐Márquez

García

Moreno-Córdoba

et al. 2016

Front. Mol. Biosci.

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“…The kis/kid (killing suppression/killing determinant) type II TA system (pemI/pemK in plasmid R100 is identical to kis/kid) is encoded adjacent to the RepFII replicon of plasmid R1 and represents an example where the Kid (PemK) toxin is a sequence-specific RNase, thereby inhibiting translation of cellular mRNAs (53). It has also been shown that in case of a too-low-copy-number state before cell division, the Kid toxin can not only inhibit cell growth and division, but also stimulate plasmid replication by specifically inactivating the mRNA encoding the negative regulator CopB (26,54,55). The Kis/Kid type II TA system belongs to the MazEF superfamily (MazF CDD protein domain family: cl00995).…”

Section: Toxin-antitoxin Modules: Deadly Partners For Stable Maintenancementioning

confidence: 99%

Spread and Persistence of Virulence and Antibiotic Resistance Genes: A Ride on the F Plasmid Conjugation Module

Koraimann

2018

EcoSal Plus

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The F plasmid or F-factor is a large, 100-kbp, circular conjugative plasmid of and was originally described as a vector for horizontal gene transfer and gene recombination in the late 1940s. Since then, F and related F-like plasmids have served as role models for bacterial conjugation. At present, more than 200 different F-like plasmids with highly related DNA transfer genes, including those for the assembly of a type IV secretion apparatus, are completely sequenced. They belong to the phylogenetically related MOBA group. F-like plasmids are present in enterobacterial hosts isolated from clinical as well as environmental samples all over the world. As conjugative plasmids, F-like plasmids carry genetic modules enabling plasmid replication, stable maintenance, and DNA transfer. In this plasmid backbone of approximately 60 kbp, the DNA transfer genes occupy the largest and mostly conserved part. Subgroups of MOBA plasmids can be defined based on the similarity of TraJ, a protein required for DNA transfer gene expression. In addition, F-like plasmids harbor accessory cargo genes, frequently embedded within transposons and/or integrons, which harness their host bacteria with antibiotic resistance and virulence genes, causing increasingly severe problems for the treatment of infectious diseases. Here, I focus on key genetic elements and their encoded proteins present on the F-factor and other typical F-like plasmids belonging to the MOBA group of conjugative plasmids.

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“…Plasmid maintenance linked to the coordination of TAs with plasmid replication was initially reported by the Diaz-Orejas laboratory on the kis-kid TA encoded by plasmid R1 ( Ruiz-Echevarría et al, 1995a , b ), and further analyzed ( Pimentel et al, 2005 ; López-Villarejo et al, 2012 , 2015 ). Additional work revealed a further coordination of the kis-kid TA with cell cycle functions ( Pimentel et al, 2014 ).…”

Section: Functional Overlaps Between Chromosomal and Plasmid-encoded mentioning

confidence: 99%

The Importance of the Expendable: Toxin–Antitoxin Genes in Plasmids and Chromosomes

2017

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Toxin–antitoxin (TA) genes were first reported in plasmids and were considered expendable genetic cassettes involved in the stable maintenance of the plasmid replicon by interfering with growth and/or viability of bacteria in which the plasmid was lost. TAs were later found in bacterial chromosomes and also in integrated mobile genetic elements; they were proposed to be involved in the bacterial response to stressful situations. At present, 100s of TAs have been identified and classified in up to six families (I to VI), with those belonging to the type II (constituted by two protein components) being the most studied. Based on well-characterized examples of several type II TAs, we discuss in this review that irrespective of their locations in plasmids or chromosomes, TAs functionally overlap as indicated by: (i) in both locations they can mediate the maintenance of genetic elements to which they are physical linked, and (ii) they can induce persistence or virulence in response to stress situations. Examples of functional confluences in homologous TA systems with different locations are also given. We also consider whether the physiological role of TAs is due to their genetic organization as operons or to their inherent properties, like the short lifespan of the antitoxin component.

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Coupling between the Basic Replicon and the Kis-Kid Maintenance System of Plasmid R1: Modulation by Kis Antitoxin Levels and Involvement in Control of Plasmid Replication

Cited by 10 publications

References 38 publications

Stabilization of the Virulence Plasmid pSLT of Salmonella Typhimurium by Three Maintenance Systems and Its Evaluation by Using a New Stability Test

Stabilization of the Virulence Plasmid pSLT of Salmonella Typhimurium by Three Maintenance Systems and Its Evaluation by Using a New Stability Test

Spread and Persistence of Virulence and Antibiotic Resistance Genes: A Ride on the F Plasmid Conjugation Module

The Importance of the Expendable: Toxin–Antitoxin Genes in Plasmids and Chromosomes

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