Mutational specificities of environmental carcinogens in the lacl gene of Escherichia coli H. V: DNA sequence analysis of mutations in bacteria recovered from the liver of Swiss mice exposed to 1,2-dimethylhydrazine, azoxymethane, and methylazoxymethanolacetate
- Department of Radiation Genetics and Chemical Mutagenesis, Sylvius Laboratory, University of Leiden (Netherlands)
The host-mediated assay (HMA) was used to determine the spectra of mutations induced in the lacl gene of Escherichia coli cells recovered from the livers of Swiss mice exposed to the carcinogens 1,2-dimethylhydrazine (SDMH), azoxymethane (AOM), and methylazoxymethanolacetate (MAMA). These spectra were further compared with changes induced by dimethylnitrosamine (DMNA) in the HMA methodology. A total of 177 independent lacl mutations arising in the HMA following exposure to SDMH, AOM, and MAMA were analyzed. Single-base substitutions accounted for 97% of all mutations analyzed. The vast majority of the single-base substitutions consisted of G:C----A:T transitions (94% of all mutations). The remaining mutations consisted of A:T----G:C transitions (3% of all mutations) while non-base substitutions accounted for only 3% of the total mutagenesis. The latter mutations consisted of one frameshift mutation and four lacO deletions. The distribution of G:C----A:T transitions induced by the three chemicals in the first 200 bp of the lacl gene was not random, but rather clustered at sites where a target guanine was flanked at the 5{prime} site by a purine residue.
- OSTI ID:
- 5388843
- Journal Information:
- Mol. Carcinog; (United States), Vol. 4:3; ISSN 0899-1987
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALKYLATING AGENTS
MUTAGENESIS
NITROSAMINES
CARCINOGENS
DNA SEQUENCING
ESCHERICHIA COLI
GENE MUTATIONS
LIVER
MICE
AMINES
ANIMALS
BACTERIA
BODY
DIGESTIVE SYSTEM
GLANDS
MAMMALS
MICROORGANISMS
MUTATIONS
NITROSO COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
RODENTS
STRUCTURAL CHEMICAL ANALYSIS
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology