Different mutational profiles induced by N-nitroso-N-ethylurea: Effects of dose and error-prone DNA repair and correlations with DNA adducts

M. Zielenska, Joseph Guttenplan, J. B. Guttenplan

Research output: Contribution to journalArticle

Abstract

The DNA adducts and mutational profile produced by N-nitroso-N-ethylurea (ENU) in Salmonella are examined. The adduct profile produced by ENU in isolated DNA and at two doses in Salmonella were similar, with one exception: O6-ethylguanine (O6-EtG) was not detected at the low dose in Salmonella. This adduct was presumably repaired by a constitutive repair system. The premutagenic adducts, O2-ethylthymidine (O2-EtdT) and O4-ethylthymidine (O4-EtdT) were detected, with the former adduct present at higher levels. The mutational profile was also determined at the same doses by utilizing a system involving a series of histidine auxotrophs of Salmonella with differing mutagenic specificities and a further subclassification of the revertants. Four different patterns of mutagenesis were observed; these were dependent on dose and on the presence or absence of the plasmid pKM101. The mutational spectrum produced at the higher dose in strains without the plasmid consisted mainly of GC→AT transitions. At the high dose, in strains harboring pKM101, three base changes contributed importantly to the mutational spectrum: GC→AT, AT→GC, and AT→CG. At the low dose in the strains without pKM101, little mutagenesis was observed, and in strains containing pKM101, mutagenesis was greatly enhanced with the most frequent mutations resulting from AT→GC and AT→CG base changes. O6-EtG was presumably responsible for the bulk of the GC→AT transitions at the high dose. Calculations and evidence are presented indicating that O2-EtdT is responsible for at least some of the mutagenesis that occurs at AT base pairs. O4-EtdT and O2-EtdT are probably responsible for a major fraction of the AT→GC transitions, and we suggest that error-prone repair activity acting on O2-EtdT and/or O4-EtdT results in the AT→CG transversions.

Original languageEnglish (US)
Pages (from-to)473-485
Number of pages13
JournalEnvironmental and Molecular Mutagenesis
Volume11
Issue number4
StatePublished - 1988

Fingerprint

Mutagenesis
Salmonella
DNA Adducts
DNA Repair
repair
Repair
DNA
Plasmids
plasmid
Histidine
Base Pairing
Mutation
ethylurea
dose
effect
Aeromonas hydrophilia lipase-acyltransferase
mutation
salmonella

ASJC Scopus subject areas

  • Genetics
  • Environmental Science(all)
  • Environmental Chemistry
  • Health, Toxicology and Mutagenesis
  • Genetics(clinical)
  • Toxicology

Cite this

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title = "Different mutational profiles induced by N-nitroso-N-ethylurea: Effects of dose and error-prone DNA repair and correlations with DNA adducts",
abstract = "The DNA adducts and mutational profile produced by N-nitroso-N-ethylurea (ENU) in Salmonella are examined. The adduct profile produced by ENU in isolated DNA and at two doses in Salmonella were similar, with one exception: O6-ethylguanine (O6-EtG) was not detected at the low dose in Salmonella. This adduct was presumably repaired by a constitutive repair system. The premutagenic adducts, O2-ethylthymidine (O2-EtdT) and O4-ethylthymidine (O4-EtdT) were detected, with the former adduct present at higher levels. The mutational profile was also determined at the same doses by utilizing a system involving a series of histidine auxotrophs of Salmonella with differing mutagenic specificities and a further subclassification of the revertants. Four different patterns of mutagenesis were observed; these were dependent on dose and on the presence or absence of the plasmid pKM101. The mutational spectrum produced at the higher dose in strains without the plasmid consisted mainly of GC→AT transitions. At the high dose, in strains harboring pKM101, three base changes contributed importantly to the mutational spectrum: GC→AT, AT→GC, and AT→CG. At the low dose in the strains without pKM101, little mutagenesis was observed, and in strains containing pKM101, mutagenesis was greatly enhanced with the most frequent mutations resulting from AT→GC and AT→CG base changes. O6-EtG was presumably responsible for the bulk of the GC→AT transitions at the high dose. Calculations and evidence are presented indicating that O2-EtdT is responsible for at least some of the mutagenesis that occurs at AT base pairs. O4-EtdT and O2-EtdT are probably responsible for a major fraction of the AT→GC transitions, and we suggest that error-prone repair activity acting on O2-EtdT and/or O4-EtdT results in the AT→CG transversions.",
author = "M. Zielenska and Joseph Guttenplan and Guttenplan, {J. B.}",
year = "1988",
language = "English (US)",
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pages = "473--485",
journal = "Environmental and Molecular Mutagenesis",
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T1 - Different mutational profiles induced by N-nitroso-N-ethylurea

T2 - Effects of dose and error-prone DNA repair and correlations with DNA adducts

AU - Zielenska, M.

AU - Guttenplan, Joseph

AU - Guttenplan, J. B.

PY - 1988

Y1 - 1988

N2 - The DNA adducts and mutational profile produced by N-nitroso-N-ethylurea (ENU) in Salmonella are examined. The adduct profile produced by ENU in isolated DNA and at two doses in Salmonella were similar, with one exception: O6-ethylguanine (O6-EtG) was not detected at the low dose in Salmonella. This adduct was presumably repaired by a constitutive repair system. The premutagenic adducts, O2-ethylthymidine (O2-EtdT) and O4-ethylthymidine (O4-EtdT) were detected, with the former adduct present at higher levels. The mutational profile was also determined at the same doses by utilizing a system involving a series of histidine auxotrophs of Salmonella with differing mutagenic specificities and a further subclassification of the revertants. Four different patterns of mutagenesis were observed; these were dependent on dose and on the presence or absence of the plasmid pKM101. The mutational spectrum produced at the higher dose in strains without the plasmid consisted mainly of GC→AT transitions. At the high dose, in strains harboring pKM101, three base changes contributed importantly to the mutational spectrum: GC→AT, AT→GC, and AT→CG. At the low dose in the strains without pKM101, little mutagenesis was observed, and in strains containing pKM101, mutagenesis was greatly enhanced with the most frequent mutations resulting from AT→GC and AT→CG base changes. O6-EtG was presumably responsible for the bulk of the GC→AT transitions at the high dose. Calculations and evidence are presented indicating that O2-EtdT is responsible for at least some of the mutagenesis that occurs at AT base pairs. O4-EtdT and O2-EtdT are probably responsible for a major fraction of the AT→GC transitions, and we suggest that error-prone repair activity acting on O2-EtdT and/or O4-EtdT results in the AT→CG transversions.

AB - The DNA adducts and mutational profile produced by N-nitroso-N-ethylurea (ENU) in Salmonella are examined. The adduct profile produced by ENU in isolated DNA and at two doses in Salmonella were similar, with one exception: O6-ethylguanine (O6-EtG) was not detected at the low dose in Salmonella. This adduct was presumably repaired by a constitutive repair system. The premutagenic adducts, O2-ethylthymidine (O2-EtdT) and O4-ethylthymidine (O4-EtdT) were detected, with the former adduct present at higher levels. The mutational profile was also determined at the same doses by utilizing a system involving a series of histidine auxotrophs of Salmonella with differing mutagenic specificities and a further subclassification of the revertants. Four different patterns of mutagenesis were observed; these were dependent on dose and on the presence or absence of the plasmid pKM101. The mutational spectrum produced at the higher dose in strains without the plasmid consisted mainly of GC→AT transitions. At the high dose, in strains harboring pKM101, three base changes contributed importantly to the mutational spectrum: GC→AT, AT→GC, and AT→CG. At the low dose in the strains without pKM101, little mutagenesis was observed, and in strains containing pKM101, mutagenesis was greatly enhanced with the most frequent mutations resulting from AT→GC and AT→CG base changes. O6-EtG was presumably responsible for the bulk of the GC→AT transitions at the high dose. Calculations and evidence are presented indicating that O2-EtdT is responsible for at least some of the mutagenesis that occurs at AT base pairs. O4-EtdT and O2-EtdT are probably responsible for a major fraction of the AT→GC transitions, and we suggest that error-prone repair activity acting on O2-EtdT and/or O4-EtdT results in the AT→CG transversions.

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EP - 485

JO - Environmental and Molecular Mutagenesis

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