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. 1979 Jan;137(1):568–573. doi: 10.1128/jb.137.1.568-573.1979

Isolation and characterization of amber mutations in the lexA gene of Escherichia coli K-12.

L Z Pacelli, S H Edmiston, D W Mount
PMCID: PMC218484  PMID: 368030

Abstract

We describe the isolation and characterization of amber mutations in the lexA gene of Escherichia coli K-12. These mutations, designated spr(Am), were isolated and characterized in a lexA tif sfi genetic background. They abolished the sensitivity of the strain to UV light and resulted in high rates of synthesis of recA protein. Phage lambda+ failed to lysogenize the strains as observed with similar strains carrying non-amber spr mutations described previously, thereby indicating a constitutive expression of the phage induction pathway. Introduction of an amber suppressor mutation into a strain bearing the spr(Am) mutation restored expression of the LexA mutant phenotype. We conclude that spr mutations either inactivate or prevent synthesis of the lexA gene product and that loss of this product results in constitutive expression of the E. coli induction system in the tif sfi genetic background.

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Selected References

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

  1. Bachmann B. J., Low K. B., Taylor A. L. Recalibrated linkage map of Escherichia coli K-12. Bacteriol Rev. 1976 Mar;40(1):116–167. doi: 10.1128/br.40.1.116-167.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. CLARK A. J., MARGULIES A. D. ISOLATION AND CHARACTERIZATION OF RECOMBINATION-DEFICIENT MUTANTS OF ESCHERICHIA COLI K12. Proc Natl Acad Sci U S A. 1965 Feb;53:451–459. doi: 10.1073/pnas.53.2.451. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Castellazzi M., George J., Buttin G. [Prophage induction and cell division in E. coli. II. Linked (recA, zab) and unlinked (lex) suppressors of tif-1-mediated induction and filamentation]. Mol Gen Genet. 1972;119(2):153–174. doi: 10.1007/BF00269134. [DOI] [PubMed] [Google Scholar]
  4. DAVIS B. D., MINGIOLI E. S. Mutants of Escherichia coli requiring methionine or vitamin B12. J Bacteriol. 1950 Jul;60(1):17–28. doi: 10.1128/jb.60.1.17-28.1950. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. George J., Castellazzi M., Buttin G. Prophage induction and cell division in E. coli. III. Mutations sfiA and sfiB restore division in tif and lon strains and permit the expression of mutator properties of tif. Mol Gen Genet. 1975 Oct 22;140(4):309–332. [PubMed] [Google Scholar]
  6. Gudas L. J., Mount D. W. Identification of the recA (tif) gene product of Escherichia coli. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5280–5284. doi: 10.1073/pnas.74.12.5280. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Gudas L. J., Pardee A. B. DNA synthesis inhibition and the induction of protein X in Escherichia coli. J Mol Biol. 1976 Mar 15;101(4):459–477. doi: 10.1016/0022-2836(76)90240-0. [DOI] [PubMed] [Google Scholar]
  8. Gudas L. J. The induction of protein X in DNA repair and cell division mutants of Escherichia coli. J Mol Biol. 1976 Jul 5;104(3):567–587. doi: 10.1016/0022-2836(76)90121-2. [DOI] [PubMed] [Google Scholar]
  9. Inouye M., Pardee A. B. Changes of membrane proteins and their relation to deoxyribonucleic acid synthesis and cell division of Escherichia coli. J Biol Chem. 1970 Nov 10;245(21):5813–5819. [PubMed] [Google Scholar]
  10. Kaplan S., Stretton A. O., Brenner S. Amber suppressors: efficiency of chain propagation and suppressor specific amino acids. J Mol Biol. 1965 Dec;14(2):528–533. doi: 10.1016/s0022-2836(65)80202-9. [DOI] [PubMed] [Google Scholar]
  11. LURIA S. E., BURROUS J. W. Hybridization between Escherichia coli and Shigella. J Bacteriol. 1957 Oct;74(4):461–476. doi: 10.1128/jb.74.4.461-476.1957. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Laemmli U. K., Favre M. Maturation of the head of bacteriophage T4. I. DNA packaging events. J Mol Biol. 1973 Nov 15;80(4):575–599. doi: 10.1016/0022-2836(73)90198-8. [DOI] [PubMed] [Google Scholar]
  13. Little J. W., Hanawalt P. C. Induction of protein X in Escherichia coli. Mol Gen Genet. 1977 Feb 15;150(3):237–248. doi: 10.1007/BF00268122. [DOI] [PubMed] [Google Scholar]
  14. Little J. W., Kleid D. G. Escherichia coli protein X is the recA gene product. J Biol Chem. 1977 Sep 25;252(18):6251–6252. [PubMed] [Google Scholar]
  15. McEntee K. Protein X is the product of the recA gene of Escherichia coli. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5275–5279. doi: 10.1073/pnas.74.12.5275. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Moody E. E., Hayes W. Chromosome transfer by autonomous transmissible plasmids: the role of the bacterial recombination (rec) system. J Bacteriol. 1972 Jul;111(1):80–85. doi: 10.1128/jb.111.1.80-85.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Mound D. W., Walker A. C., Kosel C. Suppression of lex mutations affecting deoxyribonucleic acid repair in Escherichia coli K-12 by closely linked thermosensitive mutations. J Bacteriol. 1973 Nov;116(2):950–956. doi: 10.1128/jb.116.2.950-956.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Mount D. W. A mutant of Escherichia coli showing constitutive expression of the lysogenic induction and error-prone DNA repair pathways. Proc Natl Acad Sci U S A. 1977 Jan;74(1):300–304. doi: 10.1073/pnas.74.1.300. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Mount D. W., Kosel C. Ultraviolet light-induced mutation in UV-resistant, thermosensitive derivatives of lexA-strains of Escherichia coli K-12. Mol Gen Genet. 1975;136(2):95–106. doi: 10.1007/BF00272033. [DOI] [PubMed] [Google Scholar]
  20. Mount D. W., Low K. B., Edmiston S. J. Dominant mutations (lex) in Escherichia coli K-12 which affect radiation sensitivity and frequency of ultraviolet lght-induced mutations. J Bacteriol. 1972 Nov;112(2):886–893. doi: 10.1128/jb.112.2.886-893.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Roberts J. W., Roberts C. W. Proteolytic cleavage of bacteriophage lambda repressor in induction. Proc Natl Acad Sci U S A. 1975 Jan;72(1):147–151. doi: 10.1073/pnas.72.1.147. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. West S. C., Emmerson P. T. Induction of protein synthesis in Escherichia coli following UV- or gamma-irradiation, mitomycin C treatment or tif Expression. Mol Gen Genet. 1977 Feb 28;151(1):57–67. doi: 10.1007/BF00446913. [DOI] [PubMed] [Google Scholar]
  23. Witkin E. M. Ultraviolet mutagenesis and inducible DNA repair in Escherichia coli. Bacteriol Rev. 1976 Dec;40(4):869–907. doi: 10.1128/br.40.4.869-907.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]

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