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J Bacteriol. Jan 1994; 176(2): 531–534.
PMCID: PMC205081

Regulation of the Escherichia coli hfq gene encoding the host factor for phage Q beta.


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. The synthesis rate of HF-I at the exponential-growth phase is higher than at the stationary phase, and it increases concomitantly with the increase in cell growth rate. The intracellular level of HF-I is about 30,000 to 60,000 molecules per cell, the majority being associated with ribosomes as one of the salt wash proteins. Taken together, we suggest that HF-I is one of the growth-related proteins.

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Selected References

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  • Blumenthal T, Carmichael GG. RNA replication: function and structure of Qbeta-replicase. Annu Rev Biochem. 1979;48:525–548. [PubMed]
  • 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):3607–3612. [PubMed]
  • DuBow MS, Ryan T, Young RA, Blumenthal T. Host factor for coliphage Q beta RNA replication: presence in procaryotes and association with the 30S ribosomal subunit in Escherichia coli. Mol Gen Genet. 1977 May 20;153(1):39–43. [PubMed]
  • Eikhom TS, Stockley DJ, Spiegelman S. Direct participation of a host protein in the replication of viral RNA in vitro. Proc Natl Acad Sci U S A. 1968 Feb;59(2):506–512. [PMC free article] [PubMed]
  • Enami M, Ishihama A. Biosynthesis of RNA polymerase in Escherichia coli. XII. Noncoordinate synthesis of core enzyme subunits after suppression of cell growth. Mol Gen Genet. 1982;185(3):373–378. [PubMed]
  • Franze de Fernandez MT, Eoyang L, August JT. Factor fraction required for the synthesis of bacteriophage Qbeta-RNA. Nature. 1968 Aug 10;219(5154):588–590. [PubMed]
  • Franze de Fernandez MT, Hayward WS, August JT. Bacterial proteins required for replication of phage Q ribonucleic acid. Pruification and properties of host factor I, a ribonucleic acid-binding protein. J Biol Chem. 1972 Feb 10;247(3):824–831. [PubMed]
  • Haruna I, Spiegelman S. Recognition of size and sequence by an RNA replicase. Proc Natl Acad Sci U S A. 1965 Oct;54(4):1189–1193. [PMC free article] [PubMed]
  • Igarashi K, Ishihama A. Bipartite functional map of the E. coli RNA polymerase alpha subunit: involvement of the C-terminal region in transcription activation by cAMP-CRP. Cell. 1991 Jun 14;65(6):1015–1022. [PubMed]
  • Iwakura Y, Ito K, Ishihama A. Biosynthesis of RNA polymerase in Escherichia coli. I. Control of RNA polymerase content at various growth rates. Mol Gen Genet. 1974;133(1):1–23. [PubMed]
  • Kajitani M, Ishihama A. Identification and sequence determination of the host factor gene for bacteriophage Q beta. Nucleic Acids Res. 1991 Mar 11;19(5):1063–1066. [PMC free article] [PubMed]
  • Kamen R, Kondo M, Römer W, Weissmann C. Reconstitution of Q replicase lacking subunit with protein-synthesis-interference factor i. Eur J Biochem. 1972 Nov 21;31(1):44–51. [PubMed]
  • Kawakami K, Saitoh T, Ishihama A. Biosynthesis of RNA polymerase in Escherichia coli. IX. Growth-dependent variations in the synthesis rate, content and distribution of RNA polymerase. Mol Gen Genet. 1979 Jul 13;174(2):107–116. [PubMed]
  • Senear AW, Steitz JA. Site-specific interaction of Qbeta host factor and ribosomal protein S1 with Qbeta and R17 bacteriophage RNAs. J Biol Chem. 1976 Apr 10;251(7):1902–1912. [PubMed]
  • Shapiro L, Franze de Fernandez MT, August JT. Resolution of two factors required in the Q-beta-RNA polymerase reaction. Nature. 1968 Nov 2;220(5166):478–480. [PubMed]
  • Wada A. Analysis of Escherichia coli ribosomal proteins by an improved two dimensional gel electrophoresis. I. Detection of four new proteins. J Biochem. 1986 Dec;100(6):1583–1594. [PubMed]
  • Wada A, Yamazaki Y, Fujita N, Ishihama A. Structure and probable genetic location of a "ribosome modulation factor" associated with 100S ribosomes in stationary-phase Escherichia coli cells. Proc Natl Acad Sci U S A. 1990 Apr;87(7):2657–2661. [PMC free article] [PubMed]

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