TY - JOUR
T1 - Insights into the cotranscriptional and translational control mechanisms of the Escherichia coli tbpA thiamin pyrophosphate riboswitch
AU - Grondin, Jonathan P.
AU - Geffroy, Mélanie
AU - Simoneau-Roy, Maxime
AU - Chauvier, Adrien
AU - Turcotte, Pierre
AU - St-Pierre, Patrick
AU - Dubé, Audrey
AU - Moreau, Julie
AU - Massé, Eric
AU - Penedo, J. Carlos
AU - Lafontaine, Daniel A.
N1 - Funding: This work was supported by the Canadian Institutes of Health Research, the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Fonds de recherche du Québec en Natures et Technologies (FRQNT). J.C.P. thanks the School of Biology at the University of St Andrews for financial support.
PY - 2024/10/17
Y1 - 2024/10/17
N2 - Riboswitches regulate gene expression by modulating their structure upon metabolite binding. These RNA orchestrate several layers of regulation to achieve genetic control. Although Escherichia coli riboswitches modulate translation initiation, several cases have been reported where riboswitches also modulate mRNA levels. Here, we characterize the regulation mechanisms of the thiamin pyrophosphate (TPP) tbpA riboswitch in E. coli. Our results indicate that the tbpA riboswitch modulates both levels of translation and transcription and that TPP sensing is achieved more efficiently cotranscriptionally than post-transcriptionally. The preference for cotranscriptional binding is also observed when monitoring the TPP-dependent inhibition of translation initiation. Using single-molecule approaches, we observe that the aptamer domain freely fluctuates between two main structures involved in TPP recognition. Our results suggest that translation initiation is controlled through the ligand-dependent stabilization of the riboswitch structure. This study demonstrates that riboswitch cotranscriptional sensing is the primary determinant in controlling translation and mRNA levels.
AB - Riboswitches regulate gene expression by modulating their structure upon metabolite binding. These RNA orchestrate several layers of regulation to achieve genetic control. Although Escherichia coli riboswitches modulate translation initiation, several cases have been reported where riboswitches also modulate mRNA levels. Here, we characterize the regulation mechanisms of the thiamin pyrophosphate (TPP) tbpA riboswitch in E. coli. Our results indicate that the tbpA riboswitch modulates both levels of translation and transcription and that TPP sensing is achieved more efficiently cotranscriptionally than post-transcriptionally. The preference for cotranscriptional binding is also observed when monitoring the TPP-dependent inhibition of translation initiation. Using single-molecule approaches, we observe that the aptamer domain freely fluctuates between two main structures involved in TPP recognition. Our results suggest that translation initiation is controlled through the ligand-dependent stabilization of the riboswitch structure. This study demonstrates that riboswitch cotranscriptional sensing is the primary determinant in controlling translation and mRNA levels.
U2 - 10.1038/s42003-024-07008-5
DO - 10.1038/s42003-024-07008-5
M3 - Article
SN - 2399-3642
VL - 7
JO - Communications Biology
JF - Communications Biology
M1 - 1345
ER -