Usually found in gram-positive bacteria, the T box leader sequence is an RNA element that controls gene expression through the regulation of translation by binding directly to a specific tRNA and sensing its aminoacylation state.

[6] Although the exact mechanism of T box leader is still unclear and currently being studied, it has recently been recognized as a member of an expanding group of RNAs that are phylogenetically conserved across many gram-positive bacteria.

[2] They are structurally complex and able to directly sense physiological signals which results in the control of downstream gene expression.

[1] The stem I region forms an arched conformation, with the apex containing a complex loop-loop interaction between the conserved adenine-guanine bulge and distal loop.

[8] If the length or orientation of these two recognition points is altered or mismatched, the T box riboswitch and tRNA complex is disrupted, and proper functioning of transcriptional regulation cannot occur.