RNA antitoxins

Curr Opin Microbiol. 2007 Apr;10(2):117-24. doi: 10.1016/j.mib.2007.03.003. Epub 2007 Mar 21.


Recent genomic analyses revealed a surprisingly large number of toxin-antitoxin loci in free-living prokaryotes. The antitoxins are proteins or antisense RNAs that counteract the toxins. Two antisense RNA-regulated toxin-antitoxin gene families, hok/sok and ldr, are unrelated sequence-wise but have strikingly similar properties at the level of gene and RNA organization. Recently, two SOS-induced toxins were found to be regulated by RNA antitoxins. One such toxin, SymE, exhibits similarity with MazE antitoxin and, surprisingly, inhibits translation. Thus, it is possible that an ancestral antitoxin gene evolved into the present toxin gene (symE) whose translation is repressed by an RNA antitoxin (SymR).

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Bacteria / genetics*
  • Bacteria / metabolism
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Bacterial Toxins / antagonists & inhibitors*
  • Bacterial Toxins / metabolism*
  • DNA-Binding Proteins / metabolism
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / metabolism
  • Plasmids
  • RNA / genetics*
  • RNA, Antisense / metabolism*
  • RNA, Bacterial / metabolism*


  • Bacterial Proteins
  • Bacterial Toxins
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • Hok protein, E coli
  • LdrD protein, E coli
  • MazE protein, E coli
  • RNA, Antisense
  • RNA, Bacterial
  • Sok antisense RNA, E coli
  • RNA