Article ; Online: An upstream Hfq binding site in the fhlA mRNA leader region facilitates the OxyS-fhlA interaction.
2010 Volume 5, Issue 9
Abstract: Background: To survive, bacteria must be able to adapt to environmental stresses. Small regulatory RNAs have been implicated as intermediates in a variety of stress-response pathways allowing dynamic gene regulation. The RNA binding protein Hfq ... ...
| Abstract | Background: To survive, bacteria must be able to adapt to environmental stresses. Small regulatory RNAs have been implicated as intermediates in a variety of stress-response pathways allowing dynamic gene regulation. The RNA binding protein Hfq facilitates this process in many cases, helping sRNAs base pair with their target mRNAs and initiate gene regulation. Although Hfq has been identified as a critical component in many RNPs, the manner by which Hfq controls these interactions is not known. Methodology/principal findings: To test the requirement of Hfq in these mRNA-sRNA complexes, the OxyS-fhlA system was used as a model. OxyS is induced in response to oxidative stress and down regulates the translation of fhlA, a gene encoding a transcriptional activator for formate metabolism. Biophysical characterization of this system previously used a minimal construct of the fhlA mRNA which inadvertently removed a critical element within the leader sequence of this mRNA that effected thermodynamics and kinetics for the interaction with Hfq. Conclusions/significance: Herein, we report thermodynamic, kinetic and structural mapping studies during binary and ternary complex formation between Hfq, OxyS and fhlA mRNA. Hfq binds fhlA mRNA using both the proximal and distal surfaces and stimulates association kinetics between the sRNA and mRNA but remains bound to fhlA forming a ternary complex. The upstream Hfq binding element within fhlA is similar to (ARN)(x) elements recently identified in other mRNAs regulated by Hfq. This work leads to a kinetic model for the dynamics of these complexes and the regulation of gene expression by bacterial sRNAs. |
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| MeSH term(s) | 5' Untranslated Regions ; Base Sequence ; Binding Sites ; Escherichia coli/chemistry ; Escherichia coli/genetics ; Escherichia coli/metabolism ; Escherichia coli Proteins/chemistry ; Escherichia coli Proteins/genetics ; Escherichia coli Proteins/metabolism ; Host Factor 1 Protein/genetics ; Host Factor 1 Protein/metabolism ; Models, Molecular ; Molecular Sequence Data ; Nucleic Acid Conformation ; Protein Binding ; RNA, Messenger/chemistry ; RNA, Messenger/genetics ; RNA, Messenger/metabolism ; Repressor Proteins/genetics ; Repressor Proteins/metabolism ; Trans-Activators/chemistry ; Trans-Activators/genetics ; Trans-Activators/metabolism |
| Chemical Substances | 5' Untranslated Regions ; Escherichia coli Proteins ; Hfq protein, E coli ; Host Factor 1 Protein ; RNA, Messenger ; Repressor Proteins ; Trans-Activators ; oxyS small RNA, E coli ; fhlA protein, E coli (131689-36-6) |
| Language | English |
| Publishing date | 2010-09-28 |
| Publishing country | United States |
| Document type | Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't |
| ZDB-ID | 2267670-3 |
| ISSN | 1932-6203 ; 1932-6203 |
| ISSN (online) | 1932-6203 |
| ISSN | 1932-6203 |
| DOI | 10.1371/journal.pone.0013028 |
| Database | MEDical Literature Analysis and Retrieval System OnLINE |
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