T-box

The T-box element is ann RNA switch that controls genes involved in amino acid metabolism.

In the absence of an amino acid, the uncharged tRNA binds the T-box region in the leader region of the mRNA of the controlled gene/ operon and thereby prevents the formation of a transcription terminator. The result is gene expression of the target gene in the absence of the specific amino acid.

Genes controlled by T-box elements

• Induction by alanine limitation
  • alaS

• Induction by aspartate limitation
  • hisS-aspS

• Induction by cysteine limitation
  • cysE-cysS-mrnC-yacO-yacP

• Induction by glycine limitation
  • glyQ-glyS

• Induction by histidine limitation
  • hisS-aspS

• Induction by isoleucine limitation
  • ileS

• Induction by leucine limitation
  • leuS

• Induction by phenyalanine limitation
  • pheS-pheT

• Induction by serine limitation
  • serS

• Induction by threonine limitation
  • thrS, thrZ

• Induction by tryptophan limitation
  • rtpA-ycbK

Reviews on T-box regulation

Ana Gutiérrez-Preciado, Tina M Henkin, Frank J Grundy, Charles Yanofsky, Enrique Merino
Biochemical features and functional implications of the RNA-based T-box regulatory mechanism.
Microbiol Mol Biol Rev: 2009, 73(1);36-61
[PubMed:19258532] [WorldCat.org] [DOI] (I p)