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Interaction of the RNA chaperone Hfq with mRNAs: direct and indirect roles of Hfq in iron metabolism of Escherichia coli.
- Source :
-
Molecular microbiology [Mol Microbiol] 2003 Nov; Vol. 50 (3), pp. 897-909. - Publication Year :
- 2003
-
Abstract
- The Escherichia coli Sm-like host factor I (Hfq) is thought to play direct and indirect roles in post-transcriptional regulation by targeting small regulatory RNAs and mRNAs. In this study, we have used proteomics to identify new mRNA targets of Hfq. We have identified 11 candidate proteins, synthesis of which was differentially affected in a hfq- background. The effect of Hfq on some of the corresponding mRNAs including fur, gapA, metF, ppiB and sodB mRNA was assessed, using different in vitro and in vivo methods. This allowed us to distinguish between direct and indirect effects of Hfq in modulating the translational activities of these mRNAs. From the collection of mRNAs tested, only fur and sodB mRNA, encoding the master regulator of iron metabolism and the iron superoxide dismutase, respectively, were found to be regulated by Hfq. Fur is known to be a negative regulator of transcription of the small RNA RyhB. Mutations in the sodB leader and compensating mutations in RyhB revealed that RyhB in turn represses translation of sodB mRNA, explaining the previously reported positive control of sodB by Fur. These data assign a role to Hfq in regulation of iron uptake and in switching off of iron scavenger genes.
- Subjects :
- 5,10-Methylenetetrahydrofolate Reductase (FADH2) genetics
Bacterial Proteins genetics
Bacterial Proteins metabolism
Base Sequence
Carrier Proteins genetics
Cyclophilins genetics
Escherichia coli genetics
Escherichia coli Proteins genetics
Gene Expression Regulation, Bacterial
Host Factor 1 Protein genetics
Molecular Chaperones genetics
Molecular Chaperones metabolism
Molecular Sequence Data
Peptidylprolyl Isomerase
Protein Biosynthesis
Proteomics methods
RNA Stability
RNA, Small Nuclear genetics
RNA, Small Nuclear metabolism
Repressor Proteins genetics
Repressor Proteins metabolism
Escherichia coli metabolism
Escherichia coli Proteins metabolism
Host Factor 1 Protein metabolism
Iron metabolism
RNA, Messenger metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0950-382X
- Volume :
- 50
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Molecular microbiology
- Publication Type :
- Academic Journal
- Accession number :
- 14617150
- Full Text :
- https://doi.org/10.1046/j.1365-2958.2003.03727.x