hfq

Summary

Gene Symbol: hfq
Description: global sRNA chaperone; HF-I, host factor for RNA phage Q beta replication
Alias: ECK4168, JW4130
Species: Escherichia coli str. K-12 substr. MG1655

Top Publications

  1. Moll I, Afonyushkin T, Vytvytska O, Kaberdin V, Bl si U. Coincident Hfq binding and RNase E cleavage sites on mRNA and small regulatory RNAs. RNA. 2003;9:1308-14 pubmed
    The Escherichia coli RNA chaperone Hfq was discovered originally as an accessory factor of the phage Qbeta replicase...
  2. Ali Azam T, Iwata A, Nishimura A, Ueda S, Ishihama A. Growth phase-dependent variation in protein composition of the Escherichia coli nucleoid. J Bacteriol. 1999;181:6361-70 pubmed
    ..DnaA (DNA-binding protein A), Dps (DNA-binding protein from starved cells), Fis (factor for inversion stimulation), Hfq (host factor for phage Q(beta)), H-NS (histone-like nucleoid structuring protein), HU (heat-unstable nucleoid ..
  3. Sukhodolets M, Garges S. Interaction of Escherichia coli RNA polymerase with the ribosomal protein S1 and the Sm-like ATPase Hfq. Biochemistry. 2003;42:8022-34 pubmed publisher
    We report evidence that ribosomal protein S1 and nucleic acid-binding protein Hfq copurify in molar ratios with RNA polymerase (RNAP)...
  4. Repoila F, Majdalani N, Gottesman S. Small non-coding RNAs, co-ordinators of adaptation processes in Escherichia coli: the RpoS paradigm. Mol Microbiol. 2003;48:855-61 pubmed
    ..Environmental cues affect the synthesis and stability of specific sRNAs, resulting in specific sRNA-dependent translational control. ..
  5. Windbichler N, von Pelchrzim F, Mayer O, Csaszar E, Schroeder R. Isolation of small RNA-binding proteins from E. coli: evidence for frequent interaction of RNAs with RNA polymerase. RNA Biol. 2008;5:30-40 pubmed
    ..We consistently obtained RNA polymerase betasubunit, host factor Hfq and ribosomal protein S1 as sRNA-binding proteins in addition to several other factors...
  6. Viegas S, Pfeiffer V, Sittka A, Silva I, Vogel J, Arraiano C. Characterization of the role of ribonucleases in Salmonella small RNA decay. Nucleic Acids Res. 2007;35:7651-64 pubmed
    ..The stability of CsrB and CsrC seemed to be independent of the RNA chaperone, Hfq, whereas the decay of SraL and MicA was Hfq-dependent...
  7. Urban J, Vogel J. Translational control and target recognition by Escherichia coli small RNAs in vivo. Nucleic Acids Res. 2007;35:1018-37 pubmed
    ..Target regulation was also tested in mutants that lacked Hfq or RNase III, or which expressed a truncated RNase E (rne701)...
  8. Tsui H, Feng G, Winkler M. Negative regulation of mutS and mutH repair gene expression by the Hfq and RpoS global regulators of Escherichia coli K-12. J Bacteriol. 1997;179:7476-87 pubmed
    ..we tested whether the amounts of MutS, MutL, and MutH were regulated by two global regulators, RpoS (sigma38) and Hfq (HF-I [putative RNA chaperone]), which are involved in stationary-phase transition...
  9. Brennan R, Link T. Hfq structure, function and ligand binding. Curr Opin Microbiol. 2007;10:125-33 pubmed
    Recent studies on Hfq have provided a deeper understanding of the multiple functions of this pleiotropic post-transcriptional regulator. Insights into the mechanism of Hfq action have come from a variety of approaches...
  10. Nogueira T, Springer M. Post-transcriptional control by global regulators of gene expression in bacteria. Curr Opin Microbiol. 2000;3:154-8 pubmed
    ..This is the case for Hfq (HF-1), which is involved in the regulation of an increasing number of genes in Escherichia coli, and CsrA (RsmA) ..

Detail Information

Publications79

  1. Moll I, Afonyushkin T, Vytvytska O, Kaberdin V, Bl si U. Coincident Hfq binding and RNase E cleavage sites on mRNA and small regulatory RNAs. RNA. 2003;9:1308-14 pubmed
    The Escherichia coli RNA chaperone Hfq was discovered originally as an accessory factor of the phage Qbeta replicase...
  2. Ali Azam T, Iwata A, Nishimura A, Ueda S, Ishihama A. Growth phase-dependent variation in protein composition of the Escherichia coli nucleoid. J Bacteriol. 1999;181:6361-70 pubmed
    ..DnaA (DNA-binding protein A), Dps (DNA-binding protein from starved cells), Fis (factor for inversion stimulation), Hfq (host factor for phage Q(beta)), H-NS (histone-like nucleoid structuring protein), HU (heat-unstable nucleoid ..
  3. Sukhodolets M, Garges S. Interaction of Escherichia coli RNA polymerase with the ribosomal protein S1 and the Sm-like ATPase Hfq. Biochemistry. 2003;42:8022-34 pubmed publisher
    We report evidence that ribosomal protein S1 and nucleic acid-binding protein Hfq copurify in molar ratios with RNA polymerase (RNAP)...
  4. Repoila F, Majdalani N, Gottesman S. Small non-coding RNAs, co-ordinators of adaptation processes in Escherichia coli: the RpoS paradigm. Mol Microbiol. 2003;48:855-61 pubmed
    ..Environmental cues affect the synthesis and stability of specific sRNAs, resulting in specific sRNA-dependent translational control. ..
  5. Windbichler N, von Pelchrzim F, Mayer O, Csaszar E, Schroeder R. Isolation of small RNA-binding proteins from E. coli: evidence for frequent interaction of RNAs with RNA polymerase. RNA Biol. 2008;5:30-40 pubmed
    ..We consistently obtained RNA polymerase betasubunit, host factor Hfq and ribosomal protein S1 as sRNA-binding proteins in addition to several other factors...
  6. Viegas S, Pfeiffer V, Sittka A, Silva I, Vogel J, Arraiano C. Characterization of the role of ribonucleases in Salmonella small RNA decay. Nucleic Acids Res. 2007;35:7651-64 pubmed
    ..The stability of CsrB and CsrC seemed to be independent of the RNA chaperone, Hfq, whereas the decay of SraL and MicA was Hfq-dependent...
  7. Urban J, Vogel J. Translational control and target recognition by Escherichia coli small RNAs in vivo. Nucleic Acids Res. 2007;35:1018-37 pubmed
    ..Target regulation was also tested in mutants that lacked Hfq or RNase III, or which expressed a truncated RNase E (rne701)...
  8. Tsui H, Feng G, Winkler M. Negative regulation of mutS and mutH repair gene expression by the Hfq and RpoS global regulators of Escherichia coli K-12. J Bacteriol. 1997;179:7476-87 pubmed
    ..we tested whether the amounts of MutS, MutL, and MutH were regulated by two global regulators, RpoS (sigma38) and Hfq (HF-I [putative RNA chaperone]), which are involved in stationary-phase transition...
  9. Brennan R, Link T. Hfq structure, function and ligand binding. Curr Opin Microbiol. 2007;10:125-33 pubmed
    Recent studies on Hfq have provided a deeper understanding of the multiple functions of this pleiotropic post-transcriptional regulator. Insights into the mechanism of Hfq action have come from a variety of approaches...
  10. Nogueira T, Springer M. Post-transcriptional control by global regulators of gene expression in bacteria. Curr Opin Microbiol. 2000;3:154-8 pubmed
    ..This is the case for Hfq (HF-1), which is involved in the regulation of an increasing number of genes in Escherichia coli, and CsrA (RsmA) ..
  11. Udekwu K, Wagner E. Sigma E controls biogenesis of the antisense RNA MicA. Nucleic Acids Res. 2007;35:1279-88 pubmed
    ..This regulation is Hfq-dependent and occurs by MicA-dependent translational inhibition which facilitates mRNA decay...
  12. Takada A, Wachi M, Nagai K. Negative regulatory role of the Escherichia coli hfq gene in cell division. Biochem Biophys Res Commun. 1999;266:579-83 pubmed
    We found that the hfq::cat mutant strain produced minicells at high frequency...
  13. Robinson K, Orans J, Kovach A, Link T, Brennan R. Mapping Hfq-RNA interaction surfaces using tryptophan fluorescence quenching. Nucleic Acids Res. 2014;42:2736-49 pubmed publisher
    b>Hfq is a posttranscriptional riboregulator and RNA chaperone that binds small RNAs and target mRNAs to effect their annealing and message-specific regulation in response to environmental stressors...
  14. Arluison V, Hohng S, Roy R, Pellegrini O, Regnier P, Ha T. Spectroscopic observation of RNA chaperone activities of Hfq in post-transcriptional regulation by a small non-coding RNA. Nucleic Acids Res. 2007;35:999-1006 pubmed
    b>Hfq protein is vital for the function of many non-coding small (s)RNAs in bacteria but the mechanism by which Hfq facilitates the function of sRNA is still debated...
  15. Folichon M, Arluison V, Pellegrini O, Huntzinger E, Regnier P, Hajnsdorf E. The poly(A) binding protein Hfq protects RNA from RNase E and exoribonucleolytic degradation. Nucleic Acids Res. 2003;31:7302-10 pubmed
    The Hfq protein, which shares sequence and structural homology with the Sm and Lsm proteins, binds to various RNAs, primarily recognizing AU-rich single-stranded regions...
  16. Vecerek B, Rajkowitsch L, Sonnleitner E, Schroeder R, Blasi U. The C-terminal domain of Escherichia coli Hfq is required for regulation. Nucleic Acids Res. 2008;36:133-43 pubmed
    The Escherichia coli RNA chaperone Hfq is involved in riboregulation of target mRNAs by small trans-encoded non-coding (ncRNAs)...
  17. Guisbert E, Rhodius V, Ahuja N, Witkin E, Gross C. Hfq modulates the sigmaE-mediated envelope stress response and the sigma32-mediated cytoplasmic stress response in Escherichia coli. J Bacteriol. 2007;189:1963-73 pubmed
    b>Hfq, a chaperone for small noncoding RNAs, regulates many processes in Escherichia coli, including the sigma(S)-mediated general stress response...
  18. Vecerek B, Moll I, Afonyushkin T, Kaberdin V, Blasi U. Interaction of the RNA chaperone Hfq with mRNAs: direct and indirect roles of Hfq in iron metabolism of Escherichia coli. Mol Microbiol. 2003;50:897-909 pubmed
    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...
  19. Vecerek B, Moll I, Blasi U. Translational autocontrol of the Escherichia coli hfq RNA chaperone gene. RNA. 2005;11:976-84 pubmed
    The conserved bacterial RNA chaperone Hfq has been shown to play an important role in post-transcriptional regulation. Here, we demonstrate that Hfq synthesis is autoregulated at the translational level...
  20. Thompson K, Rhodius V, Gottesman S. SigmaE regulates and is regulated by a small RNA in Escherichia coli. J Bacteriol. 2007;189:4243-56 pubmed
    RybB is a small, Hfq-binding noncoding RNA originally identified in a screen of conserved intergenic regions in Escherichia coli...
  21. Azam T, Ishihama A. Twelve species of the nucleoid-associated protein from Escherichia coli. Sequence recognition specificity and DNA binding affinity. J Biol Chem. 1999;274:33105-13 pubmed
    ..DnaA (DNA-binding protein A), Dps (DNA-binding protein from starved cells), Fis (factor for inversion stimulation), Hfq (host factor for phage Q(beta)), H-NS (histone-like nucleoid structuring protein), HU (heat-unstable nucleoid ..
  22. Peng Y, Curtis J, Fang X, Woodson S. Structural model of an mRNA in complex with the bacterial chaperone Hfq. Proc Natl Acad Sci U S A. 2014;111:17134-9 pubmed publisher
    The Sm-like protein Hfq (host factor Q-beta phage) facilitates regulation by bacterial small noncoding RNAs (sRNAs) in response to stress and other environmental signals...
  23. Udekwu K, Darfeuille F, Vogel J, Reimegård J, Holmqvist E, Wagner E. Hfq-dependent regulation of OmpA synthesis is mediated by an antisense RNA. Genes Dev. 2005;19:2355-66 pubmed
    ..Regulation of ompA (outer membrane protein A), previously attributed to Hfq/mRNA binding, is lost upon deletion of the micA gene, whereas overexpression of MicA inhibits the synthesis of OmpA...
  24. Brescia C, Mikulecky P, Feig A, Sledjeski D. Identification of the Hfq-binding site on DsrA RNA: Hfq binds without altering DsrA secondary structure. RNA. 2003;9:33-43 pubmed
    ..DsrA activates the translation of RpoS while repressing the translation of H-NS. The RNA-binding protein Hfq is necessary for DsrA to function in vivo...
  25. Muffler A, Traulsen D, Fischer D, Lange R, Hengge Aronis R. The RNA-binding protein HF-I plays a global regulatory role which is largely, but not exclusively, due to its role in expression of the sigmaS subunit of RNA polymerase in Escherichia coli. J Bacteriol. 1997;179:297-300 pubmed
    The hfq-encoded RNA-binding protein HF-I has long been known as a host factor for phage Qbeta RNA replication and has recently been shown to be essential for translation of rpoS, which encodes the sigmaS subunit of RNA polymerase...
  26. Wachi M, Takada A, Nagai K. Overproduction of the outer-membrane proteins FepA and FhuE responsible for iron transport in Escherichia coli hfq::cat mutant. Biochem Biophys Res Commun. 1999;264:525-9 pubmed
    We found that 82- and 76-kDa proteins in the outer-membrane fractions were overproduced in the hfq::cat mutant cells when grown in synthetic media...
  27. Jousselin A, Metzinger L, Felden B. On the facultative requirement of the bacterial RNA chaperone, Hfq. Trends Microbiol. 2009;17:399-405 pubmed publisher
    The pleiotropic post-transcriptional regulator Hfq is an RNA chaperone that facilitates pairing interactions between small regulatory RNAs (sRNAs) and their mRNA targets in several bacteria...
  28. Lee T, Feig A. The RNA binding protein Hfq interacts specifically with tRNAs. RNA. 2008;14:514-23 pubmed publisher
    b>Hfq is an RNA binding protein that has been studied extensively for its role in the biology of small noncoding RNAs (ncRNAs) in bacteria, where it facilitates post-transcriptional gene regulation during stress responses...
  29. Morita T, Maki K, Aiba H. RNase E-based ribonucleoprotein complexes: mechanical basis of mRNA destabilization mediated by bacterial noncoding RNAs. Genes Dev. 2005;19:2176-86 pubmed
    b>Hfq-binding antisense small RNAs of Escherichia coli, SgrS and RyhB, mediate the destabilization of target mRNAs in an RNase E-dependent manner...
  30. Link T, Valentin Hansen P, Brennan R. Structure of Escherichia coli Hfq bound to polyriboadenylate RNA. Proc Natl Acad Sci U S A. 2009;106:19292-7 pubmed publisher
    b>Hfq is a small, highly abundant hexameric protein that is found in many bacteria and plays a critical role in mRNA expression and RNA stability...
  31. Azam T, Hiraga S, Ishihama A. Two types of localization of the DNA-binding proteins within the Escherichia coli nucleoid. Genes Cells. 2000;5:613-26 pubmed
    ..Here we show that the majority of Hfq is present in cytoplasm together with ribosomal proteins L7/L12 and RMF. The DNA-binding proteins of E...
  32. Vytvytska O, Moll I, Kaberdin V, von Gabain A, Blasi U. Hfq (HF1) stimulates ompA mRNA decay by interfering with ribosome binding. Genes Dev. 2000;14:1109-18 pubmed
    ..Recently, host factor I (Hfq/HF1) was shown to be involved in the regulation of ompA mRNA stability under slow growth conditions...
  33. Mass E, Gottesman S. A small RNA regulates the expression of genes involved in iron metabolism in Escherichia coli. Proc Natl Acad Sci U S A. 2002;99:4620-5 pubmed publisher
    ..RyhB requires the RNA-binding protein, Hfq, for activity...
  34. Arluison V, Folichon M, Marco S, Derreumaux P, Pellegrini O, Seguin J, et al. The C-terminal domain of Escherichia coli Hfq increases the stability of the hexamer. Eur J Biochem. 2004;271:1258-65 pubmed
    The Hfq (Host factor 1) polypeptide is a nucleic acid binding protein involved in the synthesis of many polypeptides. Hfq particularly affects the translation and the stability of several RNAs...
  35. Mohanty B, Maples V, Kushner S. The Sm-like protein Hfq regulates polyadenylation dependent mRNA decay in Escherichia coli. Mol Microbiol. 2004;54:905-20 pubmed
    ..Here we show that the inactivation of Hfq (hfq), an abundant RNA-binding protein, leads to the reduction in the ability of PAP I to add poly(A) tails at the ..
  36. Sauter C, Basquin J, Suck D. Sm-like proteins in Eubacteria: the crystal structure of the Hfq protein from Escherichia coli. Nucleic Acids Res. 2003;31:4091-8 pubmed
    The Hfq protein was discovered in Escherichia coli in the early seventies as a host factor for the Qbeta phage RNA replication...
  37. Le Derout J, Folichon M, Briani F, Deh G, R gnier P, Hajnsdorf E. Hfq affects the length and the frequency of short oligo(A) tails at the 3' end of Escherichia coli rpsO mRNAs. Nucleic Acids Res. 2003;31:4017-23 pubmed
    ..and distribution of poly(A) tails at the 3'-end of rpsO transcripts in vivo in the presence and absence of Hfq, a host factor that in vitro stimulates the activity of PAP I, and found that Hfq affects all three parameters...
  38. Vytvytska O, Jakobsen J, Balcunaite G, Andersen J, Baccarini M, von Gabain A. Host factor I, Hfq, binds to Escherichia coli ompA mRNA in a growth rate-dependent fashion and regulates its stability. Proc Natl Acad Sci U S A. 1998;95:14118-23 pubmed
    ..An RNA-binding protein with affinity for the 5' untranslated region ompA was purified and identified as Hfq, a host factor initially recognized for its function in phage Qbeta replication...
  39. Updegrove T, Wartell R. The influence of Escherichia coli Hfq mutations on RNA binding and sRNA•mRNA duplex formation in rpoS riboregulation. Biochim Biophys Acta. 2011;1809:532-40 pubmed publisher
    The Escherichia coli RNA binding protein Hfq plays an important role in regulating mRNA translation through its interactions with small non-coding RNAs (sRNAs) and specific mRNAs sites...
  40. Arluison V, Derreumaux P, Allemand F, Folichon M, Hajnsdorf E, R gnier P. Structural Modelling of the Sm-like Protein Hfq from Escherichia coli. J Mol Biol. 2002;320:705-12 pubmed
    The Hfq polypeptide of Escherichia coli is a nucleic acid-binding protein involved in the expression of many proteins...
  41. Antal M, Bordeau V, Douchin V, Felden B. A small bacterial RNA regulates a putative ABC transporter. J Biol Chem. 2005;280:7901-8 pubmed
    ..In vivo, RydC binds to the RNA-binding protein Hfq, and it is unstable when Hfq is absent...
  42. Moll I, Leitsch D, Steinhauser T, Bl si U. RNA chaperone activity of the Sm-like Hfq protein. EMBO Rep. 2003;4:284-9 pubmed publisher
    The Escherichia coli Sm-like host factor I (Hfq) protein is thought to function in post-transcriptional regulation by modulating the function of small regulatory RNAs. Hfq also interferes with ribosome binding on E...
  43. Kawamoto H, Morita T, Shimizu A, Inada T, Aiba H. Implication of membrane localization of target mRNA in the action of a small RNA: mechanism of post-transcriptional regulation of glucose transporter in Escherichia coli. Genes Dev. 2005;19:328-38 pubmed
    ..The stimulation of ptsG-crp mRNA degradation was completely eliminated when either the hfq or sgrS gene is inactivated...
  44. Altuvia S. Identification of bacterial small non-coding RNAs: experimental approaches. Curr Opin Microbiol. 2007;10:257-61 pubmed
    ..Consequently, unique sRNAs such as those that are species-specific, sRNA genes that are transcribed under unique conditions or genes located on the antisense strand of protein-encoding genes, were probably missed. ..
  45. Scheibe M, Bonin S, Hajnsdorf E, Betat H, Mörl M. Hfq stimulates the activity of the CCA-adding enzyme. BMC Mol Biol. 2007;8:92 pubmed
    The bacterial Sm-like protein Hfq is known as an important regulator involved in many reactions of RNA metabolism. A prominent function of Hfq is the stimulation of RNA polyadenylation catalyzed by E. coli poly(A) polymerase I (PAP)...
  46. Sonnleitner E, Napetschnig J, Afonyushkin T, Ecker K, Vecerek B, Moll I, et al. Functional effects of variants of the RNA chaperone Hfq. Biochem Biophys Res Commun. 2004;323:1017-23 pubmed
    The ring-shaped RNA chaperone Hfq has recently received much attention owing to its multiple roles in RNA metabolism...
  47. Soper T, Mandin P, Majdalani N, Gottesman S, Woodson S. Positive regulation by small RNAs and the role of Hfq. Proc Natl Acad Sci U S A. 2010;107:9602-7 pubmed publisher
    ..of gene expression by pairing with mRNAs; in Escherichia coli, this regulation often requires the RNA chaperone Hfq. Three small regulatory RNAs (sRNAs), DsrA, RprA, and ArcZ, positively regulate translation of the sigma factor ..
  48. Kawamoto H, Koide Y, Morita T, Aiba H. Base-pairing requirement for RNA silencing by a bacterial small RNA and acceleration of duplex formation by Hfq. Mol Microbiol. 2006;61:1013-22 pubmed
    SgrS is an Hfq-binding small antisense RNA that is induced upon phosphosugar stress...
  49. Kajitani M, Kato A, Wada A, Inokuchi Y, Ishihama A. Regulation of the Escherichia coli hfq gene encoding the host factor for phage Q beta. J Bacteriol. 1994;176:531-4 pubmed
    The host factor (HF-I) for phage Q beta RNA replication is a small protein of 102 amino acid residues encoded by the hfq gene at 94.8 min on the Escherichia coli chromosome...
  50. Zhang A, Altuvia S, Tiwari A, Argaman L, Hengge Aronis R, Storz G. The OxyS regulatory RNA represses rpoS translation and binds the Hfq (HF-I) protein. EMBO J. 1998;17:6061-8 pubmed
    ..This repression is dependent on the hfq-encoded RNA-binding protein (also denoted host factor I, HF-I)...
  51. 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;97:1501-5 pubmed
    ..Here, we show that host factor Hfq is also involved in poly(A) tail metabolism...
  52. Sledjeski D, Whitman C, Zhang A. Hfq is necessary for regulation by the untranslated RNA DsrA. J Bacteriol. 2001;183:1997-2005 pubmed
    ..b>Hfq is an E. coli protein necessary for the in vitro and in vivo replication of the RNA phage Qbeta...
  53. M ller T, Franch T, H jrup P, Keene D, B chinger H, Brennan R, et al. Hfq: a bacterial Sm-like protein that mediates RNA-RNA interaction. Mol Cell. 2002;9:23-30 pubmed
    The bacterial Hfq protein modulates the stability or the translation of mRNAs and has recently been shown to interact with small regulatory RNAs in E. coli...
  54. Hengge Aronis R. Signal transduction and regulatory mechanisms involved in control of the sigma(S) (RpoS) subunit of RNA polymerase. Microbiol Mol Biol Rev. 2002;66:373-95, table of contents pubmed
    ..rpoS translation is controlled by several proteins (Hfq and HU) and small regulatory RNAs that probably affect the secondary structure of rpoS mRNA...
  55. Geissmann T, Touati D. Hfq, a new chaperoning role: binding to messenger RNA determines access for small RNA regulator. EMBO J. 2004;23:396-405 pubmed
    The Sm-like protein Hfq is involved in post-transcriptional regulation by small, noncoding RNAs in Escherichia coli that act by base pairing...
  56. Mass E, Escorcia F, Gottesman S. Coupled degradation of a small regulatory RNA and its mRNA targets in Escherichia coli. Genes Dev. 2003;17:2374-83 pubmed publisher
    ..RyhB requires the RNA chaperone Hfq. In the absence of Hfq, RyhB is unstable, even when general transcription is inhibited; degradation is dependent ..
  57. Soper T, Woodson S. The rpoS mRNA leader recruits Hfq to facilitate annealing with DsrA sRNA. RNA. 2008;14:1907-17 pubmed publisher
    ..regulate the response of bacteria to environmental stress in conjunction with the Sm-like RNA binding protein Hfq. DsrA sRNA stimulates translation of the RpoS stress response factor in Escherichia coli by base-pairing with the 5'..
  58. Zhang A, Wassarman K, Rosenow C, Tjaden B, Storz G, Gottesman S. Global analysis of small RNA and mRNA targets of Hfq. Mol Microbiol. 2003;50:1111-24 pubmed
    b>Hfq, a bacterial member of the Sm family of RNA-binding proteins, is required for the action of many small regulatory RNAs that act by basepairing with target mRNAs. Hfq binds this family of small RNAs efficiently...
  59. Arluison V, Mura C, Guzmán M, Liquier J, Pellegrini O, Gingery M, et al. Three-dimensional structures of fibrillar Sm proteins: Hfq and other Sm-like proteins. J Mol Biol. 2006;356:86-96 pubmed
    b>Hfq is a nucleic acid-binding protein that functions as a global regulator of gene expression by virtue of its interactions with several small, non-coding RNA species...
  60. Johansen J, Rasmussen A, Overgaard M, Valentin Hansen P. Conserved small non-coding RNAs that belong to the sigmaE regulon: role in down-regulation of outer membrane proteins. J Mol Biol. 2006;364:1-8 pubmed
    ..Here, we show that two Hfq-binding small RNAs, MicA and RybB, are under positive control of sigmaE...
  61. Valentin Hansen P, Eriksen M, Udesen C. The bacterial Sm-like protein Hfq: a key player in RNA transactions. Mol Microbiol. 2004;51:1525-33 pubmed
    The conserved RNA-binding protein Hfq, originally discovered in Escherichia coli as a host factor for Qbeta replicase, has emerged as a pleiotropic regulator that modulates the stability or the translation of an increasing number of ..
  62. Sharma A, Payne S. Induction of expression of hfq by DksA is essential for Shigella flexneri virulence. Mol Microbiol. 2006;62:469-79 pubmed
    b>Hfq plays an important role in cellular physiology by regulating the expression of several genes. Hfq synthesis in Escherichia coli is subject to auto-repression at translational level...
  63. Sun X, Wartell R. Escherichia coli Hfq binds A18 and DsrA domain II with similar 2:1 Hfq6/RNA stoichiometry using different surface sites. Biochemistry. 2006;45:4875-87 pubmed
    b>Hfq is a RNA-binding protein in Escherichia coli that plays an essential role in post-transcriptional regulation of mRNAs by facilitating pairing of noncoding RNAs (ncRNAs) to mRNA target sites. Recent work has provided evidence that E...
  64. Moon K, Gottesman S. Competition among Hfq-binding small RNAs in Escherichia coli. Mol Microbiol. 2011;82:1545-62 pubmed publisher
    ..RNAs (sRNAs) regulate translation and mRNA stability by pairing with target mRNAs, dependent upon the RNA chaperone Hfq. Hfq, related to the Lsm/Sm families of splicing proteins, binds the sRNAs and stabilizes them in vivo and ..
  65. Takada A, Wachi M, Kaidow A, Takamura M, Nagai K. DNA binding properties of the hfq gene product of Escherichia coli. Biochem Biophys Res Commun. 1997;236:576-9 pubmed
    ..N-terminal amino acid residues of the 15-kDa protein was identical with the host factor I (HF-I) encoded by the hfq gene at 95 min on the Escherichia coli chromosome map, which is known to be required for bacteriophage Qbeta ..
  66. Hussein R, Lim H. Disruption of small RNA signaling caused by competition for Hfq. Proc Natl Acad Sci U S A. 2011;108:1110-5 pubmed publisher
    ..At the center of this large sRNA regulatory network is the Hfq protein...
  67. Zhang A, Wassarman K, Ortega J, Steven A, Storz G. The Sm-like Hfq protein increases OxyS RNA interaction with target mRNAs. Mol Cell. 2002;9:11-22 pubmed
    The Escherichia coli host factor I, Hfq, binds to many small regulatory RNAs and is required for OxyS RNA repression of fhlA and rpoS mRNA translation...
  68. Rasmussen A, Eriksen M, Gilany K, Udesen C, Franch T, Petersen C, et al. Regulation of ompA mRNA stability: the role of a small regulatory RNA in growth phase-dependent control. Mol Microbiol. 2005;58:1421-9 pubmed
    ..b>Hfq binds to this region, is essential for controlling the stability and has been suggested to directly regulate ompA ..
  69. Folichon M, Allemand F, Regnier P, Hajnsdorf E. Stimulation of poly(A) synthesis by Escherichia coli poly(A)polymerase I is correlated with Hfq binding to poly(A) tails. FEBS J. 2005;272:454-63 pubmed
    The bacterial Lsm protein, host factor I (Hfq), is an RNA chaperone involved in many types of RNA transactions such as replication and stability, control of small RNA activity and polyadenylation...
  70. Sonnleitner E, Moll I, Bl si U. Functional replacement of the Escherichia coli hfq gene by the homologue of Pseudomonas aeruginosa. Microbiology. 2002;148:883-91 pubmed publisher
    The 102 aa Hfq protein of Escherichia coli (Hfq(Ec)) was first described as a host factor required for phage Qbeta replication. More recently, Hfq was shown to affect the stability of several E...
  71. Ziolkowska K, Derreumaux P, Folichon M, Pellegrini O, Regnier P, Boni I, et al. Hfq variant with altered RNA binding functions. Nucleic Acids Res. 2006;34:709-20 pubmed
    The interaction between Hfq and RNA is central to multiple regulatory processes...
  72. Tsui H, Leung H, Winkler M. Characterization of broadly pleiotropic phenotypes caused by an hfq insertion mutation in Escherichia coli K-12. Mol Microbiol. 1994;13:35-49 pubmed
    The region immediately downstream from the miaA tRNA modification gene at 94.8 min contains the hfq gene and the hflA region, which are important in the bacteriophage Q beta and lambda life cycles...
  73. Aiba H. Mechanism of RNA silencing by Hfq-binding small RNAs. Curr Opin Microbiol. 2007;10:134-9 pubmed
    ..small RNAs SgrS and RyhB in Escherichia coli form a specific ribonucleoprotein complex with RNAse E and Hfq resulting in translation inhibition, RNAse E-dependent degradation of target mRNAs...
  74. Vecerek B, Beich Frandsen M, Resch A, Blasi U. Translational activation of rpoS mRNA by the non-coding RNA DsrA and Hfq does not require ribosome binding. Nucleic Acids Res. 2010;38:1284-93 pubmed publisher
    ..the stationary phase sigma-factor, sigma(S), involves the small regulatory RNA (sRNA) DsrA and the RNA chaperone Hfq. The Hfq-mediated DsrA-rpoS interaction relieves an intramolecular secondary structure that impedes ribosome access ..
  75. Mikulecky P, Kaw M, Brescia C, Takach J, Sledjeski D, Feig A. Escherichia coli Hfq has distinct interaction surfaces for DsrA, rpoS and poly(A) RNAs. Nat Struct Mol Biol. 2004;11:1206-14 pubmed
    The bacterial Sm-like protein Hfq facilitates RNA-RNA interactions involved in post-transcriptional regulation of the stress response. Specifically, Hfq helps pair noncoding RNAs (ncRNAs) with complementary regions of target mRNAs...
  76. Muffler A, Fischer D, Hengge Aronis R. The RNA-binding protein HF-I, known as a host factor for phage Qbeta RNA replication, is essential for rpoS translation in Escherichia coli. Genes Dev. 1996;10:1143-51 pubmed
    ..Here, we identify the hfq-encoded RNA-binding protein HF-I, which has been known previously only as a host factor for the replication of ..