Dataset Information

Escherichia coli toxin/antitoxin pair MqsR/MqsA regulate toxin CspD.

ABSTRACT: Previously we identified that the Escherichia coli protein MqsR (YgiU) functions as a toxin and that it is involved in the regulation of motility by quorum sensing signal autoinducer-2 (AI-2). Furthermore, MqsR is directly associated with biofilm development and is linked to the development of persister cells. Here we show that MqsR and MqsA (YgiT) are a toxin/antitoxin (TA) pair, which, in significant difference to other TA pairs, regulates additional loci besides its own. We have recently identified that MqsR functions as an RNase. However, using three sets of whole-transcriptome studies and two nickel-enrichment DNA binding microarrays coupled with cell survival studies in which MqsR was overproduced in isogenic mutants, we identified eight genes (cspD, clpX, clpP, lon, yfjZ, relB, relE and hokA) that are involved in a mode of MqsR toxicity in addition to its RNase activity. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) showed that (i) the MqsR/MqsA complex (and MqsA alone) represses the toxin gene cspD, (ii) MqsR overproduction induces cspD, (iii) stress induces cspD, and (iv) stress fails to induce cspD when MqsR/MqsA are overproduced or when mqsRA is deleted. Electrophoretic mobility shift assays show that the MqsA/MqsR complex binds the promoter of cspD. In addition, proteases Lon and ClpXP are necessary for MqsR toxicity. Together, these results indicate the MqsR/MqsA complex represses cspD which may be derepressed by titrating MqsA with MqsR or by degrading MqsA via stress conditions through proteases Lon and ClpXP. Hence, we demonstrate that the MqsR/MqsA TA system controls cell physiology via its own toxicity as well as through its regulation of another toxin, CspD.

SUBMITTER: Kim Y

PROVIDER: S-EPMC3980499 | biostudies-literature | 2010 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Escherichia coli toxin/antitoxin pair MqsR/MqsA regulate toxin CspD.

Kim Younghoon Y Wang Xiaoxue X Zhang Xue-Song XS Grigoriu Simina S Page Rebecca R Peti Wolfgang W Wood Thomas K TK

Environmental microbiology 20100126 5

Previously we identified that the Escherichia coli protein MqsR (YgiU) functions as a toxin and that it is involved in the regulation of motility by quorum sensing signal autoinducer-2 (AI-2). Furthermore, MqsR is directly associated with biofilm development and is linked to the development of persister cells. Here we show that MqsR and MqsA (YgiT) are a toxin/antitoxin (TA) pair, which, in significant difference to other TA pairs, regulates additional loci besides its own. We have recently iden ...[more]

PMID: 20105222

Similar Datasets

Project description:Toxin-antitoxin (TA) systems are broadly distributed modules whose biological roles remain mostly unknown. The mqsRA system is a noncanonical TA system in which the toxin and antitoxins genes are organized in operon but with the particularity that the toxin gene precedes that of the antitoxin. This system was shown to regulate global processes such as resistance to bile salts, motility, and biofilm formation. In addition, the MqsA antitoxin was shown to be a master regulator that represses the transcription of the csgD, cspD, and rpoS global regulator genes, thereby displaying a pleiotropic regulatory role. Here, we identified two promoters located in the toxin sequence driving the constitutive expression of mqsA, allowing thereby excess production of the MqsA antitoxin compared to the MqsR toxin. Our results show that both antitoxin-specific and operon promoters are not regulated by stresses such as amino acid starvation, oxidative shock, or bile salts. Moreover, we show that the MqsA antitoxin is not a global regulator as suggested, since the expression of csgD, cspD and rpoS is similar in wild-type and ΔmqsRA mutant strains. Moreover, these two strains behave similarly in terms of biofilm formation and sensitivity to oxidative stress or bile salts.IMPORTANCE There is growing controversy regarding the role of chromosomal toxin-antitoxin systems in bacterial physiology. mqsRA is a peculiar toxin-antitoxin system, as the gene encoding the toxin precedes that of the antitoxin. This system was previously shown to play a role in stress response and biofilm formation. In this work, we identified two promoters specifically driving the constitutive expression of the antitoxin, thereby decoupling the expression of antitoxin from the toxin. We also showed that mqsRA contributes neither to the regulation of biofilm formation nor to the sensitivity to oxidative stress and bile salts. Finally, we were unable to confirm that the MqsA antitoxin is a global regulator. Altogether, our data are ruling out the involvement of the mqsRA system in Escherichia coli regulatory networks.

Dataset Information

Escherichia coli toxin/antitoxin pair MqsR/MqsA regulate toxin CspD.

Publications

Escherichia coli toxin/antitoxin pair MqsR/MqsA regulate toxin CspD.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets