Comparative mutagenic efficiencies of the DNA adducts from the cooked-food-related mutagens Trp-P-2 and IQ in CHO cells

Kerry W. Brookman, E. P. Salazar, L. H. Thompson

Research output: Contribution to journalArticle

19 Scopus citations


The relationship between DNA-adduct formation and mutagenicity of two heterocyclic aromatic amines associated with cooked foods was determined in a CHO cell strain lacking nucleotide excision repair. Cells were exposed to tritiated IQ (2-amino-3-methylimidazo[4,5-F]quinoline) or Trp-P-2 (3-amino-1-methyl-5H-pyrido[4,3-b]indole) supplemented with hamster S9 microsomal fraction for metabolic activation. DNA from nuclei was isolated by DNAase-mediated elution from polycarbonate filters after RNAase and proteinase treatment. The presumed metabolites of both compounds bound to DNA in a dose-dependent fashion. Although the dose required to produce 50% cell killing was 15 times higher for IQ than Trp-P-2, the amount of radioactive material bound to DNA at that dose was about 10-fold lower with IQ. When mutations at the hprt and aprt loci were compared with the estimated levels of adducts, the calculated mutagenic efficiency of the adducts was bout 4 mutations per 1000 adducts for both compounds, assuming a target sequence of 1000 base pairs for either locus. We conclude that IQ is acting as a weak mutagen in this system because its extracellular metabolites either do not reach or do not react efficiently with the DNA of the CHO cells.

Original languageEnglish (US)
Pages (from-to)249-255
Number of pages7
JournalMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
Issue number2
StatePublished - 1985
Externally publishedYes


ASJC Scopus subject areas

  • Molecular Biology
  • Health, Toxicology and Mutagenesis
  • Medicine(all)

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