Skip to main content
PMC home page
Journal of Bacteriology logoLink to Journal of Bacteriology
. 1991 Apr;173(7):2319–2327. doi: 10.1128/jb.173.7.2319-2327.1991

Further inducibility of a constitutive system: ultrainduction of the gal operon.

J P Tokeson 1, S Garges 1, S Adhya 1
PMCID: PMC207785  PMID: 2007555

Abstract

In wild-type Escherichia coli, expression of the gal operon is negatively regulated by the Gal repressor and is induced 10- to 15-fold when the repressor is inactivated by an inducer. In strains completely deleted for galR, the gene which encodes the Gal repressor, the operon is derepressed by only 10-fold without an inducer. But this derepression is increased further by threefold during cell growth in the presence of an inducer, D-galactose or D-fucose. This phenomenon of extreme induction in the absence of Gal repressor is termed ultrainduction--a manifestation of further inducibility in a constitutive setup. Construction and characterization of gene and operon fusion strains between galE and lacZ, encoding beta-galactosidase as a reporter gene, show that ultrainduction occurs at the level of transcription and not translation. Transcription of the operon, from both the cyclic AMP-dependent P1 and the cyclic nucleotide-independent P2 promoters, is subject to ultrainduction. The wild-type galR+ gene has an epistatic effect on ultrainducibility: ultrainduction is observed only in cells devoid of Gal repressor protein. Titration experiments show the existence of an ultrainducibility factor that acts like a repressor and functions by binding to DNA segments (operators) to which Gal repressor also binds to repress the operon.

Full text

PDF
2320

Selected References

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

  1. Adhya S. L., Shapiro J. A. The galactose operon of E. coli K-12. I. Structural and pleiotropic mutations of the operon. Genetics. 1969 Jun;62(2):231–247. doi: 10.1093/genetics/62.2.231. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Adhya S., Echols H. Glucose effect and the galactose enzymes of Escherichia coli: correlation between glucose inhibition of induction and inducer transport. J Bacteriol. 1966 Sep;92(3):601–608. doi: 10.1128/jb.92.3.601-608.1966. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Adhya S., Miller W. Modulation of the two promoters of the galactose operon of Escherichia coli. Nature. 1979 Jun 7;279(5713):492–494. doi: 10.1038/279492a0. [DOI] [PubMed] [Google Scholar]
  4. BUTTIN G. M'ECANISMES R'EGULATEURS DANS LA BIOSYNTH'ESE DES ENZYMES DU M'ETABOLISME DU GALACTOSE CHEZ ESCHERICHIA COLI K12. I. LA BIOSYNTH'ESE INDUITE DE LA GALACTOKINASE ET L'INDUCTION SIMULTAN'EE DE LA S'EQUENCE ENZYMATIQUE. J Mol Biol. 1963 Aug;7:164–182. doi: 10.1016/s0022-2836(63)80044-3. [DOI] [PubMed] [Google Scholar]
  5. BUTTIN G. M'ECANISMES R'EGULATEURS DANS LA BIOSYNTH'ESE DES ENZYMES DU M'ETABOLISME DU GALACTOSE CHEZ ESCHERICHIA COLI K12. II. LE D'ETERMINISME G'EN'ETIQUE DE LA R'EGULATION. J Mol Biol. 1963 Aug;7:183–205. doi: 10.1016/s0022-2836(63)80045-5. [DOI] [PubMed] [Google Scholar]
  6. Bolivar F. Construction and characterization of new cloning vehicles. III. Derivatives of plasmid pBR322 carrying unique Eco RI sites for selection of Eco RI generated recombinant DNA molecules. Gene. 1978 Oct;4(2):121–136. doi: 10.1016/0378-1119(78)90025-2. [DOI] [PubMed] [Google Scholar]
  7. Bolivar F., Rodriguez R. L., Greene P. J., Betlach M. C., Heyneker H. L., Boyer H. W., Crosa J. H., Falkow S. Construction and characterization of new cloning vehicles. II. A multipurpose cloning system. Gene. 1977;2(2):95–113. [PubMed] [Google Scholar]
  8. Bremer E., Silhavy T. J., Weinstock G. M. Transposable lambda placMu bacteriophages for creating lacZ operon fusions and kanamycin resistance insertions in Escherichia coli. J Bacteriol. 1985 Jun;162(3):1092–1099. doi: 10.1128/jb.162.3.1092-1099.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. ECHOLS H., REZNICHEK J., ADHYA S. COMPLEMENTATION, RECOMBINATION, AND SUPPRESSION IN GALACTOSE NEGATIVE MUTANTS OF E. COLI. Proc Natl Acad Sci U S A. 1963 Aug;50:286–293. doi: 10.1073/pnas.50.2.286. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Enquist L. W., Weisberg R. A. The red plaque test: a rapid method for identification of excision defective variants of bacteriophage lambda. Virology. 1976 Jul 1;72(1):147–153. doi: 10.1016/0042-6822(76)90319-6. [DOI] [PubMed] [Google Scholar]
  11. Feiss M., Adyha S., Court D. L. Isolation of plaque-forming, galactose-transducing strains of phage lambda. Genetics. 1972 Jun;71(2):189–206. doi: 10.1093/genetics/71.2.189. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Fritz H. J., Bicknäse H., Gleumes B., Heibach C., Rosahl S., Ehring R. Characterization of two mutations in the Escherichia coli galE gene inactivating the second galactose operator and comparative studies of repressor binding. EMBO J. 1983;2(12):2129–2135. doi: 10.1002/j.1460-2075.1983.tb01713.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Gottesman M. E., Yarmolinsky M. B. Integration-negative mutants of bacteriophage lambda. J Mol Biol. 1968 Feb 14;31(3):487–505. doi: 10.1016/0022-2836(68)90423-3. [DOI] [PubMed] [Google Scholar]
  14. Haber R., Adhya S. Interaction of spatially separated protein-DNA complexes for control of gene expression: operator conversions. Proc Natl Acad Sci U S A. 1988 Dec;85(24):9683–9687. doi: 10.1073/pnas.85.24.9683. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Irani M. H., Orosz L., Adhya S. A control element within a structural gene: the gal operon of Escherichia coli. Cell. 1983 Mar;32(3):783–788. doi: 10.1016/0092-8674(83)90064-8. [DOI] [PubMed] [Google Scholar]
  16. Irani M., Musso R., Adhya S. Cyclic-AMP-dependent switch in initiation of transcription from the two promoters of the Escherichia coli gal operon: identification and assay of 5'-triphosphate ends of mRNA by GTP:RNA guanyltransferase. J Bacteriol. 1989 Mar;171(3):1623–1630. doi: 10.1128/jb.171.3.1623-1630.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Irani M., Orosz L., Busby S., Taniguchi T., Adhya S. Cyclic AMP-dependent constitutive expression of gal operon: use of repressor titration to isolate operator mutations. Proc Natl Acad Sci U S A. 1983 Aug;80(15):4775–4779. doi: 10.1073/pnas.80.15.4775. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Jordan E., Saedler H., Starlinger P. O0 and strong-polar mutations in the gal operon are insertions. Mol Gen Genet. 1968;102(4):353–363. doi: 10.1007/BF00433726. [DOI] [PubMed] [Google Scholar]
  19. KALCKAR H. M., SUNDARARAJANTA Regulatory mechanisms in the synthesis of enzymes of galactose metabolism. II. Genetic defects in galactokinase activity and their relations to its function. Cold Spring Harb Symp Quant Biol. 1961;26:227–231. doi: 10.1101/sqb.1961.026.01.027. [DOI] [PubMed] [Google Scholar]
  20. Karin M. Too many transcription factors: positive and negative interactions. New Biol. 1990 Feb;2(2):126–131. [PubMed] [Google Scholar]
  21. Majumdar A., Adhya S. Demonstration of two operator elements in gal: in vitro repressor binding studies. Proc Natl Acad Sci U S A. 1984 Oct;81(19):6100–6104. doi: 10.1073/pnas.81.19.6100. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Majumdar A., Rudikoff S., Adhya S. Purification and properties of Gal repressor:pL-galR fusion in pKC31 plasmid vector. J Biol Chem. 1987 Feb 15;262(5):2326–2331. [PubMed] [Google Scholar]
  23. Maurizi M. R., Trisler P., Gottesman S. Insertional mutagenesis of the lon gene in Escherichia coli: lon is dispensable. J Bacteriol. 1985 Dec;164(3):1124–1135. doi: 10.1128/jb.164.3.1124-1135.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Merril C., Gottesman M., Court D., Adhya S. Disco-ordinate expression of the Escherichia coli gal operon after prophage lambda induction. J Mol Biol. 1978 Jan 15;118(2):241–245. doi: 10.1016/0022-2836(78)90415-1. [DOI] [PubMed] [Google Scholar]
  25. Musso R. E., Di Lauro R., Adhya S., de Crombrugghe B. Dual control for transcription of the galactose operon by cyclic AMP and its receptor protein at two interspersed promoters. Cell. 1977 Nov;12(3):847–854. doi: 10.1016/0092-8674(77)90283-5. [DOI] [PubMed] [Google Scholar]
  26. Nakanishi S., Adhya S., Gottesman M. E., Pastan I. In vitro repression of the transcription of gas operon by purified gal repressor. Proc Natl Acad Sci U S A. 1973 Feb;70(2):334–338. doi: 10.1073/pnas.70.2.334. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Saedler H., Gullon A., Fiethen L., Starlinger P. Negative control of the galactose operon in E. coli. Mol Gen Genet. 1968;102(1):79–88. doi: 10.1007/BF00341872. [DOI] [PubMed] [Google Scholar]
  28. Shapiro J. A., Adhya S. L. The galactose operon of E. coli K-12. II. A deletion analysis of operon structure and polarity. Genetics. 1969 Jun;62(2):249–264. doi: 10.1093/genetics/62.2.249. [DOI] [PMC free article] [PubMed] [Google Scholar]

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

RESOURCES