Single transmembrane peptide DinQ modulates membrane-dependent activities

PLoS Genet. 2013;9(2):e1003260. doi: 10.1371/journal.pgen.1003260. Epub 2013 Feb 7.


The functions of several SOS regulated genes in Escherichia coli are still unknown, including dinQ. In this work we characterize dinQ and two small RNAs, agrA and agrB, with antisense complementarity to dinQ. Northern analysis revealed five dinQ transcripts, but only one transcript (+44) is actively translated. The +44 dinQ transcript translates into a toxic single transmembrane peptide localized in the inner membrane. AgrB regulates dinQ RNA by RNA interference to counteract DinQ toxicity. Thus the dinQ-agr locus shows the classical features of a type I TA system and has many similarities to the tisB-istR locus. DinQ overexpression depolarizes the cell membrane and decreases the intracellular ATP concentration, demonstrating that DinQ can modulate membrane-dependent processes. Augmented DinQ strongly inhibits marker transfer by Hfr conjugation, indicating a role in recombination. Furthermore, DinQ affects transformation of nucleoid morphology in response to UV damage. We hypothesize that DinQ is a transmembrane peptide that modulates membrane-dependent activities such as nucleoid compaction and recombination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Membrane* / genetics
  • Cell Membrane* / metabolism
  • Cell Membrane* / radiation effects
  • Cytoplasm
  • DNA Damage / radiation effects
  • Escherichia coli Proteins / genetics*
  • Escherichia coli Proteins / metabolism
  • Escherichia coli* / genetics
  • Escherichia coli* / metabolism
  • Gene Expression Regulation, Bacterial / radiation effects
  • Membrane Proteins / genetics*
  • Peptides / genetics
  • Peptides / metabolism
  • RNA, Antisense / genetics
  • RNA, Antisense / metabolism
  • RNA, Bacterial* / genetics
  • RNA, Bacterial* / metabolism
  • Recombination, Genetic / genetics
  • SOS Response, Genetics / radiation effects
  • Trans-Activators / genetics
  • Trans-Activators / metabolism
  • Ultraviolet Rays


  • ArsR protein, E coli
  • DinQ protein, E coli
  • Escherichia coli Proteins
  • Membrane Proteins
  • Peptides
  • RNA, Antisense
  • RNA, Bacterial
  • Trans-Activators

Grants and funding

The Research Council of Norway and the Norewegian Cancer Society supported this work. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.