Abstract
A wide number of bacteria have been found to govern virulence and heat shock responses using temperature-sensing RNAs known as RNA thermometers. A prime example is the agsA thermometer known to regulate the production of the AgsA heat shock protein in Salmonella enterica using a “fourU” structural motif. Using the SHAPE-Seq RNA structure-probing method in vivo and in vitro, we found that the regulator functions by a subtle shift in equilibrium RNA structure populations that lead to a partial melting of the helix containing the ribosome binding site. We also demonstrate that ribosome binding to the agsA mRNA causes changes to the thermometer structure that appear to facilitate thermometer helix unwinding. These results demonstrate how subtle RNA structural changes can govern gene expression and illuminate the function of an important bacterial regulatory motif.
Footnotes
This work was supported by the National Science Foundation Graduate Research Fellowship Program [grant number DGE-1144153 to SM] and a New Innovator Award through the National Institute of General Medical Sciences of the National Institutes of Health [grant number 1DP2GM110838 to JBL]. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
>Abbreviations
- RNA
- ribonucleic acid
- RBS
- ribosome binding site
- ROSE
- repression of heat shock gene expression
- UTR
- untranslated region
- SD
- Shine-Dalgarno
- NMR
- nuclear magnetic resonance
- SHAPE-Seq
- Selective 2’-hydroxyl acylation analyzed by primer extension sequencing
- WT
- wild-type
- SFGFP
- superfolder green fluorescent protein
- LB
- Lysogeny broth
- OD
- optical density
- 1M7
- 1-methyl-7-nitroisatoic anhydride
- DMSO
- dimethyl sulfoxide
- MFE
- minimum free energy
- MDS
- multidimensional scaling
- TIC
- translation initiation complex
