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. 1983 Jun;154(3):1329–1338. doi: 10.1128/jb.154.3.1329-1338.1983

Suppressed nonsense mutations in the araC gene of Escherichia coli provide three novel variant proteins.

J B Schecter
PMCID: PMC217608  PMID: 6343350

Abstract

A total of 400 suppressible mutations have been isolated in the araC gene of Escherichia coli. Based on deletion mapping, growth patterns when suppressed, and intragenic recombination, 37 mutants have been determined to contain unique mutations. Rapid plate assays were developed to test for each of the three AraC protein functions: inducing araBAD, repressing araBAD, and araC self-repression. The 185 mutant proteins, resulting from 37 mutants each suppressed by five different suppressors, were assayed for each of the three AraC functions. These plate assays showed that: (i) for each function, some areas of the gene map are more sensitive to mutation than other areas, and (ii) three of the mutant AraC proteins were unlike previously characterized AraC mutants. Enzyme assays on the mutant proteins confirmed their novel character. The first mutant cannot induce araBAD but retains the capacity to perform both repression functions; and the second and third can each perform one of the two repression functions better than it can perform the other. These characteristics suggest that previously proposed models of ara regulation are incomplete.

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Selected References

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

  1. Beverin S., Sheppard D. E., Park S. S. D-Fucose as a gratuitous inducer of the L-arabinose operon in strains of Escherichia coli B-r mutant in gene araC. J Bacteriol. 1971 Jul;107(1):79–86. doi: 10.1128/jb.107.1.79-86.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Chase M, Doermann A H. High Negative Interference over Short Segments of the Genetic Structure of Bacteriophage T4. Genetics. 1958 May;43(3):332–353. doi: 10.1093/genetics/43.3.332. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Coulondre C., Miller J. H., Farabaugh P. J., Gilbert W. Molecular basis of base substitution hotspots in Escherichia coli. Nature. 1978 Aug 24;274(5673):775–780. doi: 10.1038/274775a0. [DOI] [PubMed] [Google Scholar]
  4. Coulondre C., Miller J. H. Genetic studies of the lac repressor. III. Additional correlation of mutational sites with specific amino acid residues. J Mol Biol. 1977 Dec 15;117(3):525–567. doi: 10.1016/0022-2836(77)90056-0. [DOI] [PubMed] [Google Scholar]
  5. ENGLESBERG E., ANDERSON R. L., WEINBERG R., LEE N., HOFFEE P., HUTTENHAUER G., BOYER H. L-Arabinose-sensitive, L-ribulose 5-phosphate 4-epimerase-deficient mutants of Escherichia coli. J Bacteriol. 1962 Jul;84:137–146. doi: 10.1128/jb.84.1.137-146.1962. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Englesberg E., Irr J., Power J., Lee N. Positive control of enzyme synthesis by gene C in the L-arabinose system. J Bacteriol. 1965 Oct;90(4):946–957. doi: 10.1128/jb.90.4.946-957.1965. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Englesberg E., Squires C., Meronk F., Jr The L-arabinose operon in Escherichia coli B-r: a genetic demonstration of two functional states of the product of a regulator gene. Proc Natl Acad Sci U S A. 1969 Apr;62(4):1100–1107. doi: 10.1073/pnas.62.4.1100. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Hirsh J., Schleif R. In vivo experiments on the mechanism of action of L-arabinose C gene activator and lactose repressor. J Mol Biol. 1973 Nov 5;80(3):433–444. doi: 10.1016/0022-2836(73)90414-2. [DOI] [PubMed] [Google Scholar]
  9. Hirsh J., Schleif R. The araC promoter: transcription, mapping and interaction with the araBAD promoter. Cell. 1977 Jul;11(3):545–550. doi: 10.1016/0092-8674(77)90072-1. [DOI] [PubMed] [Google Scholar]
  10. Lee N. L., Gielow W. O., Wallace R. G. Mechanism of araC autoregulation and the domains of two overlapping promoters, Pc and PBAD, in the L-arabinose regulatory region of Escherichia coli. Proc Natl Acad Sci U S A. 1981 Feb;78(2):752–756. doi: 10.1073/pnas.78.2.752. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Lee N., Wilcox G., Gielow W., Arnold J., Cleary P., Englesberg E. In vitro activation of the transcription of araBAD operon by araC activator. Proc Natl Acad Sci U S A. 1974 Mar;71(3):634–638. doi: 10.1073/pnas.71.3.634. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. 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]
  13. Miyada C. G., Horwitz A. H., Cass L. G., Timko J., Wilcox G. DNA sequence of the araC regulatory gene from Escherichia coli B/r. Nucleic Acids Res. 1980 Nov 25;8(22):5267–5274. doi: 10.1093/nar/8.22.5267. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Nathanson N. M., Schleif R. Paucity of sites mutable to constitutivity in the araC activator gene of the L-arabinose operon of Escherichia coli. J Mol Biol. 1975 Jul 25;96(1):185–199. doi: 10.1016/0022-2836(75)90190-4. [DOI] [PubMed] [Google Scholar]
  15. Ogden S., Haggerty D., Stoner C. M., Kolodrubetz D., Schleif R. The Escherichia coli L-arabinose operon: binding sites of the regulatory proteins and a mechanism of positive and negative regulation. Proc Natl Acad Sci U S A. 1980 Jun;77(6):3346–3350. doi: 10.1073/pnas.77.6.3346. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Pfahl M., Stockter C., Gronenborn B. Genetic analysis of the active sites of lac repressor. Genetics. 1974 Apr;76(4):669–679. doi: 10.1093/genetics/76.4.669. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Schleif R. Fine-structure deletion map of the Escherichia coli L-arabinose operon. Proc Natl Acad Sci U S A. 1972 Nov;69(11):3479–3484. doi: 10.1073/pnas.69.11.3479. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Stoner C. M., Schleif R. Is the amino acid but not the nucleotide sequence of the Escherichia coli araC gene conserved? J Mol Biol. 1982 Feb 5;154(4):649–652. doi: 10.1016/s0022-2836(82)80020-x. [DOI] [PubMed] [Google Scholar]
  19. Wallace R. G., Lee N., Fowler A. V. The araC gene of Escherichia coli: transcriptional and translational start-points and complete nucleotide sequence. Gene. 1980 Dec;12(3-4):179–190. doi: 10.1016/0378-1119(80)90100-6. [DOI] [PubMed] [Google Scholar]

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