T-box

The T-box element is a 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 cysteine limitation

• • cysE-cysS-mrnC-yacO-yacP

• Induction by tryptophan limitation

• • rtpA-ycbK