Skip to main content
PMC home page
Journal of Bacteriology logoLink to Journal of Bacteriology
. 1987 May;169(5):2158–2164. doi: 10.1128/jb.169.5.2158-2164.1987

Regulation of the aroH operon of Escherichia coli by the tryptophan repressor.

C L Grove, R P Gunsalus
PMCID: PMC212118  PMID: 3106331

Abstract

Regulation of expression of aroH, the structural gene for the tryptophan-sensitive 3-deoxy-D-arabinoheptulosonic acid-7-phosphate synthetase, by the tryptophan repressor and its corepressor, L-tryptophan, was studied in vivo by using aroH-lacZ fusions. Protein and operon fusions were constructed on multicopy plasmids and subsequently crossed in single copy to the bacterial chromosome via the specialized transducing bacteriophage lambda RZ5. Analysis of the resulting lysogens demonstrated that aroH-lacZ expression in a trpR mutant strain varied four- to fivefold relative to an isogenic trpR+ strain under fully repressing conditions. In trpR+ strains containing either fusion, a modest (ca. 50%) change in activity was seen in response to the addition of L-tryptophan to the culture medium. These data demonstrate that aroH gene expression is only moderately regulated by the tryptophan repressor and that this regulation is at the level of transcription. Addition of L-phenylalanine, L-tyrosine, or Casamino Acids (Difco Laboratories, Detroit, Mich.) to the cell culture medium resulted in a tryptophan repressor-dependent derepression of aroH expression. We believe that this effect is caused by L-tryptophan limitation as a result of repression and feedback inhibition of the tyrosine- and phenylalanine-specific 3-deoxy-D-arabinoheptulosonic acid-7-phosphate synthetase isoenzymes. Derepression of aroH expression by the L-tryptophan analogs, 3-beta-indoleacrylic acid and indole-3-propionic acid, is also documented.

Full text

PDF

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Arvidson D. N., Bruce C., Gunsalus R. P. Interaction of the Escherichia coli trp aporepressor with its ligand, L-tryptophan. J Biol Chem. 1986 Jan 5;261(1):238–243. [PubMed] [Google Scholar]
  2. Bachmann B. J. Linkage map of Escherichia coli K-12, edition 7. Microbiol Rev. 1983 Jun;47(2):180–230. doi: 10.1128/mr.47.2.180-230.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Birnboim H. C., Doly J. A rapid alkaline extraction procedure for screening recombinant plasmid DNA. Nucleic Acids Res. 1979 Nov 24;7(6):1513–1523. doi: 10.1093/nar/7.6.1513. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Bogosian G., Somerville R. L. Analysis in vivo of factors affecting the control of transcription initiation at promoters containing target sites for trp repressor. Mol Gen Genet. 1984;193(1):110–118. doi: 10.1007/BF00327423. [DOI] [PubMed] [Google Scholar]
  5. Brown K. D. Regulation of aromatic amino acid biosynthesis Escherichia coli K12. Genetics. 1968 Sep;60(1):31–48. doi: 10.1093/genetics/60.1.31. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Camakaris H., Pittard J. Regulation of tyrosine and phenylalanine biosynthesis in Escherichia coli K-12: properties of the tyrR gene product. J Bacteriol. 1973 Sep;115(3):1135–1144. doi: 10.1128/jb.115.3.1135-1144.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Camakaris J., Pittard J. Purification and properties of 3-deoxy-D-arabionheptulosonic acid-7-phosphate synthetase (trp) from Escherichia coli. J Bacteriol. 1974 Nov;120(2):590–597. doi: 10.1128/jb.120.2.590-597.1974. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Casadaban M. J., Chou J., Cohen S. N. In vitro gene fusions that join an enzymatically active beta-galactosidase segment to amino-terminal fragments of exogenous proteins: Escherichia coli plasmid vectors for the detection and cloning of translational initiation signals. J Bacteriol. 1980 Aug;143(2):971–980. doi: 10.1128/jb.143.2.971-980.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Cornish E. C., Argyropoulos V. P., Pittard J., Davidson B. E. Structure of the Escherichia coli K12 regulatory gene tyrR. Nucleotide sequence and sites of initiation of transcription and translation. J Biol Chem. 1986 Jan 5;261(1):403–410. [PubMed] [Google Scholar]
  10. Doolittle W. F., Yanofsky C. Mutants of Escherichia coli with an altered tryptophanyl-transfer ribonucleic acid synthetase. J Bacteriol. 1968 Apr;95(4):1283–1294. doi: 10.1128/jb.95.4.1283-1294.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Fowler A. V., Zabin I. Purification, structure, and properties of hybrid beta-galactosidase proteins. J Biol Chem. 1983 Dec 10;258(23):14354–14358. [PubMed] [Google Scholar]
  12. Gowrishankar J., Pittard J. Regulation of phenylalanine biosynthesis in Escherichia coli K-12: control of transcription of the pheA operon. J Bacteriol. 1982 Jun;150(3):1130–1137. doi: 10.1128/jb.150.3.1130-1137.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Gunsalus R. P., Miguel A. G., Gunsalus G. L. Intracellular Trp repressor levels in Escherichia coli. J Bacteriol. 1986 Jul;167(1):272–278. doi: 10.1128/jb.167.1.272-278.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Gunsalus R. P., Yanofsky C. Nucleotide sequence and expression of Escherichia coli trpR, the structural gene for the trp aporepressor. Proc Natl Acad Sci U S A. 1980 Dec;77(12):7117–7121. doi: 10.1073/pnas.77.12.7117. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Gunsalus R. P., Zurawski G., Yanofsky C. Structural and functional analysis of cloned deoxyribonucleic acid containing the trpR-thr region of the Escherichia coli chromosome. J Bacteriol. 1979 Oct;140(1):106–113. doi: 10.1128/jb.140.1.106-113.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Kelley R. L., Yanofsky C. Trp aporepressor production is controlled by autogenous regulation and inefficient translation. Proc Natl Acad Sci U S A. 1982 May;79(10):3120–3124. doi: 10.1073/pnas.79.10.3120. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Miller J. H., Ganem D., Lu P., Schmitz A. Genetic studies of the lac repressor. I. Correlation of mutational sites with specific amino acid residues: construction of a colinear gene-protein map. J Mol Biol. 1977 Jan 15;109(2):275–298. doi: 10.1016/s0022-2836(77)80034-x. [DOI] [PubMed] [Google Scholar]
  18. Pittard J., Camakaris J., Wallace B. J. Inhibition of 3-deoxy-d-arabinoheptulosonic acid-7-phosphate synthetase (trp) in Escherichia coli. J Bacteriol. 1969 Mar;97(3):1242–1247. doi: 10.1128/jb.97.3.1242-1247.1969. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Rose J. K., Squires C. L., Yanofsky C., Yang H. L., Zubay G. Regulation of in vitro transcription of the tryptophan operon by purified RNA polymerase in the presence of partially purified repressor and tryptophan. Nat New Biol. 1973 Oct 3;245(144):133–137. doi: 10.1038/newbio245133a0. [DOI] [PubMed] [Google Scholar]
  20. Sanger F., Nicklen S., Coulson A. R. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. doi: 10.1073/pnas.74.12.5463. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. VOGEL H. J., BONNER D. M. Acetylornithinase of Escherichia coli: partial purification and some properties. J Biol Chem. 1956 Jan;218(1):97–106. [PubMed] [Google Scholar]
  22. Wallace B. J., Pittard J. Genetic and biochemical analysis of the isoenzymes concerned in the first reaction of aromatic biosynthesis in Escherichia coli. J Bacteriol. 1967 Jan;93(1):237–244. doi: 10.1128/jb.93.1.237-244.1967. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Yanofsky C. Comparison of regulatory and structural regions of genes of tryptophan metabolism. Mol Biol Evol. 1984 Feb;1(2):143–161. doi: 10.1093/oxfordjournals.molbev.a040307. [DOI] [PubMed] [Google Scholar]
  24. Yanofsky C., Kelley R. L., Horn V. Repression is relieved before attenuation in the trp operon of Escherichia coli as tryptophan starvation becomes increasingly severe. J Bacteriol. 1984 Jun;158(3):1018–1024. doi: 10.1128/jb.158.3.1018-1024.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Yanofsky C. Tryptophan biosynthesis in Escherichia coli. Genetic determination of the proteins involved. JAMA. 1971 Nov 15;218(7):1026–1035. [PubMed] [Google Scholar]
  26. Zurawski G., Gunsalus R. P., Brown K. D., Yanofsky C. Structure and regulation of aroH, the structural gene for the tryptophan-repressible 3-deoxy-D-arabino-heptulosonic acid-7-phosphate synthetase of Escherichia coli. J Mol Biol. 1981 Jan 5;145(1):47–73. doi: 10.1016/0022-2836(81)90334-x. [DOI] [PubMed] [Google Scholar]

Articles from Journal of Bacteriology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES