Regulation of the Bacillus subtilis trp operon by an RNA-binding protein

Mol Microbiol. 1994 Mar;11(6):991-7. doi: 10.1111/j.1365-2958.1994.tb00377.x.


The Bacillus subtilis tryptophan (trpEDCFBA) operon is regulated by transcription attenuation. Transcription is controlled by two alternative RNA secondary structures, which form in the leader transcript. In the presence of L-tryptophan, a transcription terminator forms and the operon is not expressed, whereas in the absence of tryptophan, an antiterminator structure forms allowing transcription of the operon. The mechanism of selection between these alternative structures involves a trans-acting RNA-binding regulatory protein. This protein is the product of the mtrB gene and is called TRAP for trp attenuation protein. TRAP has been shown to bind specifically to trp leader RNA, and to cause transcription of the trp operon to terminate in the leader region. The model for regulation suggests that in the presence of tryptophan, TRAP binds to the leader RNA and induces formation of the transcription terminator structure, whereas in the absence of tryptophan, the protein does not bind and the antiterminator is formed.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Bacillus subtilis / genetics*
  • Bacterial Proteins*
  • Base Sequence
  • Gene Expression Regulation, Bacterial*
  • Molecular Sequence Data
  • Operon / genetics*
  • RNA-Binding Proteins / metabolism*
  • Transcription Factors / metabolism*
  • Transcription, Genetic
  • Tryptophan / biosynthesis*


  • Bacterial Proteins
  • MtrB protein, Bacteria
  • RNA-Binding Proteins
  • Transcription Factors
  • Tryptophan