Selective translation of leaderless mRNAs by specialized ribosomes generated by MazF in Escherichia coli

Cell. 2011 Sep 30;147(1):147-57. doi: 10.1016/j.cell.2011.07.047. Epub 2011 Sep 22.


Escherichia coli (E. coli) mazEF is a stress-induced toxin-antitoxin (TA) module. The toxin MazF is an endoribonuclease that cleaves single-stranded mRNAs at ACA sequences. Here, we show that MazF cleaves at ACA sites at or closely upstream of the AUG start codon of some specific mRNAs and thereby generates leaderless mRNAs. Moreover, we provide evidence that MazF also targets 16S rRNA within 30S ribosomal subunits at the decoding center, thereby removing 43 nucleotides from the 3' terminus. As this region comprises the anti-Shine-Dalgarno (aSD) sequence that is required for translation initiation on canonical mRNAs, a subpopulation of ribosomes is formed that selectively translates the described leaderless mRNAs both in vivo and in vitro. Thus, we have discovered a modified translation machinery that is generated in response to MazF induction and that probably serves for stress adaptation in Escherichia coli.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Base Sequence
  • Codon, Initiator
  • DNA-Binding Proteins / metabolism*
  • Endoribonucleases / metabolism*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Gene Expression Regulation, Bacterial*
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Biosynthesis*
  • RNA, Bacterial / chemistry
  • RNA, Bacterial / metabolism*
  • RNA, Messenger / metabolism*
  • RNA, Ribosomal, 16S / chemistry
  • RNA, Ribosomal, 16S / metabolism
  • Ribosomal Proteins / genetics
  • Ribosome Subunits, Small, Bacterial / metabolism*
  • Stress, Physiological


  • Codon, Initiator
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • MazF protein, E coli
  • RNA, Bacterial
  • RNA, Messenger
  • RNA, Ribosomal, 16S
  • Ribosomal Proteins
  • YfiD protein, E coli
  • ribosomal protein S21
  • Endoribonucleases