| Structural highlights
Function
HFQ_ECOLI RNA chaperone that binds small regulatory RNA (sRNAs) and mRNAs to facilitate mRNA translational regulation in response to envelope stress, environmental stress and changes in metabolite concentrations. Involved in the regulation of stress responses mediated by the sigma factors RpoS, sigma-E and sigma-32. Binds with high specificity to tRNAs. In vitro, stimulates synthesis of long tails by poly(A) polymerase I. Required for RNA phage Qbeta replication.[1] [2] [3] [4] [5] Seems to play a role in persister cell formation; upon overexpression decreases persister cell formation while deletion increases persister formation.[6] [7] [8] [9] [10]
Publication Abstract from PubMed
Polynucleotide phosphorylase (PNPase) is an ancient exoribonuclease conserved in the course of evolution and is found in species as diverse as bacteria and humans. Paradoxically, Escherichia coli PNPase can act not only as an RNA degrading enzyme but also by an unknown mechanism as a chaperone for small regulatory RNAs (sRNAs), with pleiotropic consequences for gene regulation. We present structures of the ternary assembly formed by PNPase, the RNA chaperone Hfq, and sRNA and show that this complex boosts sRNA stability in vitro. Comparison of structures for PNPase in RNA carrier and degradation modes reveals how the RNA is rerouted away from the active site through interactions with Hfq and the KH and S1 domains. Together, these data explain how PNPase is repurposed to protect sRNAs from cellular ribonucleases such as RNase E and could aid RNA presentation to facilitate regulatory actions on target genes.
A cooperative PNPase-Hfq-RNA carrier complex facilitates bacterial riboregulation.,Dendooven T, Sinha D, Roeselova A, Cameron TA, De Lay NR, Luisi BF, Bandyra KJ Mol Cell. 2021 Jun 17. pii: S1097-2765(21)00445-7. doi:, 10.1016/j.molcel.2021.05.032. PMID:34157309[11]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Carmichael GG, Weber K, Niveleau A, Wahba AJ. The host factor required for RNA phage Qbeta RNA replication in vitro. Intracellular location, quantitation, and purification by polyadenylate-cellulose chromatography. J Biol Chem. 1975 May 25;250(10):3607-612. PMID:805130
- ↑ Hajnsdorf E, Regnier P. Host factor Hfq of Escherichia coli stimulates elongation of poly(A) tails by poly(A) polymerase I. Proc Natl Acad Sci U S A. 2000 Feb 15;97(4):1501-5. PMID:10677490 doi:10.1073/pnas.040549897
- ↑ Sledjeski DD, Whitman C, Zhang A. Hfq is necessary for regulation by the untranslated RNA DsrA. J Bacteriol. 2001 Mar;183(6):1997-2005. PMID:11222598 doi:10.1128/JB.183.6.1997-2005.2001
- ↑ Guisbert E, Rhodius VA, Ahuja N, Witkin E, Gross CA. Hfq modulates the sigmaE-mediated envelope stress response and the sigma32-mediated cytoplasmic stress response in Escherichia coli. J Bacteriol. 2007 Mar;189(5):1963-73. Epub 2006 Dec 8. PMID:17158661 doi:10.1128/JB.01243-06
- ↑ Kim Y, Wood TK. Toxins Hha and CspD and small RNA regulator Hfq are involved in persister cell formation through MqsR in Escherichia coli. Biochem Biophys Res Commun. 2010 Jan 1;391(1):209-13. doi:, 10.1016/j.bbrc.2009.11.033. Epub 2009 Nov 10. PMID:19909729 doi:10.1016/j.bbrc.2009.11.033
- ↑ Carmichael GG, Weber K, Niveleau A, Wahba AJ. The host factor required for RNA phage Qbeta RNA replication in vitro. Intracellular location, quantitation, and purification by polyadenylate-cellulose chromatography. J Biol Chem. 1975 May 25;250(10):3607-612. PMID:805130
- ↑ Hajnsdorf E, Regnier P. Host factor Hfq of Escherichia coli stimulates elongation of poly(A) tails by poly(A) polymerase I. Proc Natl Acad Sci U S A. 2000 Feb 15;97(4):1501-5. PMID:10677490 doi:10.1073/pnas.040549897
- ↑ Sledjeski DD, Whitman C, Zhang A. Hfq is necessary for regulation by the untranslated RNA DsrA. J Bacteriol. 2001 Mar;183(6):1997-2005. PMID:11222598 doi:10.1128/JB.183.6.1997-2005.2001
- ↑ Guisbert E, Rhodius VA, Ahuja N, Witkin E, Gross CA. Hfq modulates the sigmaE-mediated envelope stress response and the sigma32-mediated cytoplasmic stress response in Escherichia coli. J Bacteriol. 2007 Mar;189(5):1963-73. Epub 2006 Dec 8. PMID:17158661 doi:10.1128/JB.01243-06
- ↑ Kim Y, Wood TK. Toxins Hha and CspD and small RNA regulator Hfq are involved in persister cell formation through MqsR in Escherichia coli. Biochem Biophys Res Commun. 2010 Jan 1;391(1):209-13. doi:, 10.1016/j.bbrc.2009.11.033. Epub 2009 Nov 10. PMID:19909729 doi:10.1016/j.bbrc.2009.11.033
- ↑ Dendooven T, Sinha D, Roeselova A, Cameron TA, De Lay NR, Luisi BF, Bandyra KJ. A cooperative PNPase-Hfq-RNA carrier complex facilitates bacterial riboregulation. Mol Cell. 2021 Jun 17. pii: S1097-2765(21)00445-7. doi:, 10.1016/j.molcel.2021.05.032. PMID:34157309 doi:http://dx.doi.org/10.1016/j.molcel.2021.05.032
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