Type II Toxin-Antitoxin Loci: The Unusual mqsRA Locus

  • Niilo Kaldalu
  • Villu Kasari
  • Gemma Atkinson
  • Tanel Tenson


The mqsRA locus of Escherichia coli K-12 codes for a translation-independent GCU site-specific endoribonuclease MqsR and an antitoxin MqsA, which has an additional function as a transcriptional regulator of other genes. Besides binding to the regulatory region of its own promoter, the antitoxin MqsA binds to the promoter regions of cspD, rpoS, spy, and mcbR. By repressing these target genes, MqsRA participates in regulation of the general stress response and biofilm formation. Structural analyses have shown that MqsR belongs to the RelE superfamily and MqsR is thus the first known ribosome-independent mRNase belonging to this toxin family.


Persister Cell Persister Formation Alternative Transcription Start Site Lactococcus Phage Persister Frequency 
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Our research on the TA systems is supported by European Regional Development Fund through the Centre of Excellence in Chemical Biology and by grant 8822 from Estonian Science Foundation.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Niilo Kaldalu
    • 1
  • Villu Kasari
    • 1
  • Gemma Atkinson
    • 1
  • Tanel Tenson
    • 1
  1. 1.Institute of TechnologyUniversity of TartuTartuEstonia

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