Rho-dependent transcription termination: mechanisms and roles in bacterial fitness and adaptation to environmental changes

uORF-dependent attenuation-by-RDTT. (A) Diagram depicting the regulation of the E. coli tnaCAB operon by tryptophan. At high concentration, tryptophan prevents release of the ribosome from the termination codon, shielding the downstream Rut site and allowing expression of tnaAB. (B) Diagram depicting the regulation of the Bordetella pertussis tnaCAB cruR-bfrG-bp2921 operon by Cu ions. The ribosome is stalled on the cruR stop codon in absence of Cu ions, shielding the intragenic Rut site and allowing expression of the putative Cu importer bfrG. In the presence of Cu ions, the ribosome is efficiently released from the cruR stop codon, allowing RDTT and silencing of bfrG (Roy et al. 2022).