Molecular and General Genetics MGG

, Volume 224, Issue 1, pp 81–90 | Cite as

The osmZ (bglY) gene encodes the DNA-binding protein H-NS (H1a), a component of the Escherichia coli K12 nucleoid

  • Gerhard May
  • Petra Dersch
  • Martin Haardt
  • Anke Middendorf
  • Erhard Bremer


A class of trans-acting mutations, which alter the osmoregulated expression of the Escherichia coli proU operon, maps at 27 min on the chromosome in a locus we have called osmZ. Mutations in osmZ are allelic to bglY, pilG and virR, affect gene expression, increase the frequency of the site-specific DNA inversion mediating fimbrial phase variation, stimulate the formation of deletions, and influence in vivo supercoiling of reporter plasmids. We have cloned the osmZ+ gene, mapped it at 1307 kb of the E. coli restriction map, identified its gene product as a 16 kDa protein, and determined the nucleotide sequence of the osmZ+ gene. The deduced amino acid sequence for OsmZ predicts a protein of 137 amino acid residues with a calculated molecular weight of 15 530. The primary sequence of OsmZ is identical to that of H-NS (H1a), a DNA-binding protein that affects DNA topology and is known to be associated with the bacterial nucleoid. Thus, osmZ is the structural gene for the H-NS (H1a) protein. The nucleotide sequence of osmZ is almost identical to that of hns; however, hns was incorrectly located at 6.1 min on the E. coli linkage map. Increased osmZ gene dosage leads to cell filament formation, altered gene expression, and reduced frequency of fimbrial phase variation. Our results suggest that the nucleoid-associated DNA-binding protein H-NS (H1a) plays a critical role in gene expression and in determining the structure of the genetic material.

Key words

Cell morphology DNA topology Gene expression Gene mapping Osmoregulation 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Abraham JM, Freitag CS, Clements JR, Eisenstein BI (1985) An invertable element of DNA controls phase variation of type I fimbriae of Escherichia coli. Proc Natl Acad Sci USA 82:5724–5727Google Scholar
  2. Barron A, May G, Bremer E, Villarejo M (1986) Regulation of envelope protein composition during adaptation to osmotic stress in Escherichia coli. J Bacteriol 167:433–438Google Scholar
  3. Cairney J, Booth IR, Higgins CF (1985) Osmoregulation of gene expression in Salmonella typhimurium: proU encodes an osmotically induced betaine transport system. J Bacteriol 164:1224–1232Google Scholar
  4. Carter P, Beduelle H, Winter G (1985) Improved oligonucleotide site-directed mutagenesis using M13 vectors. Nucleic Acids Res 13:4431–4443Google Scholar
  5. Casadaban MJ (1976) Transposition and fusion of the lac genes to selected promoters in Escherichia coli using bacteriophage lambda and Mu. J Mol Biol 104:541–555Google Scholar
  6. Csonka LN (1989) Physiological and genetic responses of bacteria to osmotic stress. Microbiol Rev 53:121–147Google Scholar
  7. Cukier-Kahn R, Jacquet M, Gros F (1972) Two heat-resistant, low molecular weight proteins from Escherichia coli that stimulate DNA-directed RNA synthesis. Proc Natl Acad Sci USA 69:3643–3647Google Scholar
  8. de Bruijn FG, Lupski JR (1984) The usage of transposon Tn5 mutagenesis in the rapid generation of correlated physical and genetic maps of DNA segments cloned into multicopy plasmids — a review. Gene 27:131–149Google Scholar
  9. Defez R, DeFelice M (1981) Cryptic operon for β-glucoside metabolism in Escherichia coli K12: genetic evidence for a regulatory protein. Genetics 97:11–25Google Scholar
  10. Dorman CJ, Ni Bhriain N, Higgins CF (1990) DNA supercoiling and the environmental regulation of virulence gene expression in Shigella flexneri. Nature 344:789–792Google Scholar
  11. Drlica K (1987) The nucleoid. In: Neidhardt FC (ed), Escherichia coli and Salmonella typhimurium. Cellular and Molecular Biology. American Society for Microbiology, Washington, DC, pp 91–103Google Scholar
  12. Drlica K, Rouviere-Yaniv J (1987) Histonelike proteins of bacteria. Microbiol Rev 51:301–319Google Scholar
  13. Druger-Liotta J, Prange VJ, Overdier DG, Csonka LN (1987) Selection of mutations that alter the osmotic control of transcription of the Salmonella typhimurium proU operon. J Bacteriol 169:2449–2459Google Scholar
  14. Dunlap VJ, Csonka LN (1985) Osmotic regulation of L-proline transport in Salmonella typhimurium. J Bacteriol 163:296–304Google Scholar
  15. Falconi M, Gualtieri MT, La Teana A, Losso MA, Pon CL (1988) Proteins from the prokaryotic nucleoid: primary and quaternary structure of the 15-kD Escherichia coli DNA binding protein H-NS. Mol Microbiol 2:323–329Google Scholar
  16. Freitag CS, Abraham J, Clements J, Eisenstein BI (1985) Genetic analysis of the phase variation control of expression of type 1 fimbriae in Escherichia coli. J Bacteriol 162:668–675Google Scholar
  17. Glasgow AC, Hughes KT, Simon MI (1989) Bacterial DNA inversion systems. In: Berg DE, Howe MM (eds) Mobile DNA. American Society for Microbiology, Washington, DC, pp 637–659Google Scholar
  18. Gowrishankar J (1985) Identification of osmoresponsive genes in Escherichia coli: evidence for participation of potassium and proline transport systems in osmoregulation. J Bacteriol 164:434–445Google Scholar
  19. Graeme-Cook KA, May G, Bremer E, Higgins CF (1989) Osmotic regulation of porin expression: a role for DNA supercoiling. Mol Microbiol 3:1287–1294Google Scholar
  20. Groisman EA, Casadaban MJ (1986) Mini-Mu bacteriophage with plasmid replicons for in vivo cloning and lac gene fusing. J Bacteriol 168:357–364Google Scholar
  21. Gualerzi CO, Losso MA, Lammi M, Friedrich K, Pawlik RT, Canonaco MA, Gianfranceschi G, Pingoud A, Pon CL (1986) Proteins from the prokaryotic nucleoid. Structural and functional characterization of the Escherichia coli DNA-binding proteins NS (HU) and H-NS. In: Gualerzi CO, Pon CL (eds) Bacterial chromatin. Springer-Verlag, Berlin, Heidelberg, pp 101–134Google Scholar
  22. Gutierrez C, Barondess J, Manoil C, Beckwith J (1987) The use of transposon TnphoA to detect genes for cell envelope proteins subject to a common regulatory stimulus. J Mol Biol 195:289–297Google Scholar
  23. Higgins CF, Dorman C, Stirling DA, Wadell L, Booth IR, May G, Bremer E (1988) A physiological role for DNA supercoiling in the osmotic regulation of gene expression in S. typhimurium and E. coli. Cell 52:569–584Google Scholar
  24. Hiraga S, Niki H, Ogara T, Ichinose C, Mori H, Ezaki B, Jaffe A (1989) Chromosome partitioning in Escherichia coli: novel mutants producing anucleate cells. J Bacteriol 171:1496–1505Google Scholar
  25. Jacquet M, Cukier-Kahn R, Pla J, Gros F (1971) A thermostable protein factor acting on in vitro transcription. Biochem Biophys Res Commun 45:1597–1607Google Scholar
  26. Kohara Y, Akyama K, Isono K (1987) The physical map of the whole E. coli chromosome: application of a new strategy for rapid analysis and sorting of a large genomic library. Cell 50:495–508Google Scholar
  27. La Teana A, Falconi M, Scarlato V, Lammi M, Pon CL (1989) Characterization of the structural genes for the DNA-binding protein H-NS in Enterobacteriaceae. FEBS Lett 244:34–38Google Scholar
  28. Laemmli UK (1970) Cleavage of the structural proteins during assembly of bacteriophage T4. Nature 227:680–685Google Scholar
  29. Laine B, Sautiere P, Spassky A, Rimsky S (1984) A DNA-binding protein from E. coli: isolation, characterization and its relationship with proteins H1 and B1. Biochem Biophys Res Commun 119:1147–1153Google Scholar
  30. Lejeune P, Danchin A (1990) Mutations in bglY increase the frequency of spontaneous deletions in Escherichia coli K-12. Proc Natl Acad Sci USA 87:360–363Google Scholar
  31. Mahadevan S, Reynolds AE, Wright A (1987) Positive and negative regulation of the bgl operon in Escherichia coli. J Bacteriol 169:2570–2578Google Scholar
  32. Maniatis T, Fritsch EF, Sambrook J (1982) Molecular cloning: A laboratory manual. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New YorkGoogle Scholar
  33. Mann BJ, Holroyd CD, Bradbeer C, Kadner RJ (1986) Reduced activity of TonB-dependent functions in strains of Escherichia coli. FEMS Microbiol Lett 33:255–260Google Scholar
  34. Maurelli AT, Sansonetti PJ (1988) Identification of a chromosomal gene controlling temperature-regulated expression of Shigella virulence. Proc Natl Acad Sci USA 85:2820–2824Google Scholar
  35. May G, Faatz E, Villarejo M, Bremer E (1986) Binding protein dependent transport of glycine betaine and its osmotic regulation in Escherichia coli K-12. Mol Gen Genet 205:225–233Google Scholar
  36. May G, Faatz E, Lucht JM, Haardt M, Bollinger M, Bremer E (1989) Characterization of the osmoregulated Escherichia coli proU promoter and identification of ProV as a membrane-associated protein. Mol Microbiol 3:1521–1531Google Scholar
  37. Mulligan ME, Hawley DK, Entriken R, McClure WR (1984) Escherichia coli promoter sequences predict in vitro RNA polymerase selectivity. Nucleic Acids Res 12:789–800Google Scholar
  38. Norrander J, Kempe T, Messing J (1983) Construction of improved M13 vectors using oligodeoxynucleotide-directed mutagenesis. Gene 26:101–106Google Scholar
  39. Pettijohn DE (1988) Histone-like proteins and bacterial chromosome structure. J Biol Chem 263:12793–12796Google Scholar
  40. Pon CL, Calogero RA, Gualerzi CO (1988) Identification, cloning, nucleotide sequence and chromosomal map location of hns, the structural gene for Escherichia coli DNA-binding protein H-NS. Mol Gen Genet 212:199–202Google Scholar
  41. Rimsky S, Spassky A (1986) Escherichia coli protein H1a strongly compacts DNA in vitro. In: Gualerzi CO, Pon CL (eds) Bacterial chromatin. Springer-Verlag, Berlin, Heidelberg, pp 167–174Google Scholar
  42. Sancar A, Hack AM, Rupp WD (1979) Simple method for identification of plasmid coded proteins. J Bacteriol 137:692–693Google Scholar
  43. Sanger F, Nicklen S, Coulson AR (1977) DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci USA 74:5463–5467Google Scholar
  44. Schnetz K, Toloczyki C, Rak B (1987) β-glucoside (bgl) operon of Escherichia coli K-12: nucteotidesequence, genetic organization, and possible evolutionary relationship to regulatory components of two Bacillus subtilis genes. J Bacteriol 169:2579–2590Google Scholar
  45. Silhavy TJ, Berman ML, Enquist LW (1984) Experiments with gene fusions. Cold Spring Harbor Laboratory, Cold Spring Harbor, New YorkGoogle Scholar
  46. Simon R, Quandt J, Klipp W (1989) New derivatives of transposon Tn5 suitable for mobilization of replicons, generation of operon fusions and induction of genes in Gram-negative bacteria. Gene 80:161–169Google Scholar
  47. Southern EM (1975) Detection of specific sequences among DNA fragments by gel electrophoresis. J Mol Biol 98:503–517Google Scholar
  48. Spassky A, Rimsky S, Garreau H, Buc H (1984) H1a, an E. coli DNA-binding protein which accumulates in stationary phase, strongly compacts DNA in vitro. Nucleic Acids Res 12:5321–5340Google Scholar
  49. Spears PA, Schauer D, Orndorff PE (1986) Metastable regulation of type 1 pilation in Escherichia coli and isolation and characterization of a phenotypically stable mutant. J Bacteriol 168:179–185Google Scholar
  50. Sutherland L, Cairney J, Elmore MJ, Booth IR, Higgins CF (1986) Osmotic regulation of transcription: induction of the proU betaine transport gene is dependent on accumulation of intracellular potassium. J Bacteriol 168:805–814Google Scholar
  51. Takeshita S, Sato M, Toba M, Masahashi W, Hashimoto-Gotoh T (1987) High-copy-number and low-copy-number plasmid vectors for lacZ α-complementation and chloramphenicol or kanamycin selection. Gene 61:63–74Google Scholar
  52. Worcel A, Burgi E (1972) On the structure of the folded chromosome of Escherichia coli. J Mol Biol 71:127–147Google Scholar

Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • Gerhard May
    • 1
  • Petra Dersch
    • 1
  • Martin Haardt
    • 1
  • Anke Middendorf
    • 1
  • Erhard Bremer
    • 1
  1. 1.Department of BiologyUniversity of KonstanzKonstanzFederal Republic of Germany

Personalised recommendations