| 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
The RNA chaperone Hfq plays crucial roles in bacterial gene expression and is a major facilitator of small regulatory RNA (sRNA) action. The toroidal architecture of the Hfq hexamer presents three well-characterized surfaces that allow it to bind sRNAs to stabilize them and engage target transcripts. Hfq-interacting sRNAs are categorized into two classes based on the surfaces they use to bind Hfq. By characterizing a systematic alanine mutant library of Hfq to identify amino acid residues that impact survival of Escherichia coli experiencing nitrogen (N) starvation, we corroborated the important role of the three RNA-binding surfaces for Hfq function. We uncovered two, previously uncharacterized, conserved residues, V22 and G34, in the hydrophobic core of Hfq, to have a profound impact on Hfq's RNA-binding activity in vivo. Transcriptome-scale analysis revealed that V22A and G34A Hfq mutants cause widespread destabilization of both sRNA classes, to the same extent as seen in bacteria devoid of Hfq. However, the alanine substitutions at these residues resulted in only modest alteration in stability and structure of Hfq. We propose that V22 and G34 have impact on Hfq function, especially critical under cellular conditions when there is an increased demand for Hfq, such as N starvation.
Transcriptome-scale analysis uncovers conserved residues in the hydrophobic core of the bacterial RNA chaperone Hfq required for small regulatory RNA stability.,McQuail J, Krepl M, Katsuya-Gaviria K, Tabib-Salazar A, Burchell L, Bischler T, Grafenhan T, Brear P, Sponer J, Luisi BF, Wigneshweraraj S Nucleic Acids Res. 2025 Jan 24;53(3):gkaf019. doi: 10.1093/nar/gkaf019. PMID:39868539[11]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
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
- ↑ McQuail J, Krepl M, Katsuya-Gaviria K, Tabib-Salazar A, Burchell L, Bischler T, Gräfenhan T, Brear P, Šponer J, Luisi BF, Wigneshweraraj S. Transcriptome-scale analysis uncovers conserved residues in the hydrophobic core of the bacterial RNA chaperone Hfq required for small regulatory RNA stability. Nucleic Acids Res. 2025 Jan 24;53(3):gkaf019. PMID:39868539 doi:10.1093/nar/gkaf019
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