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DNA fingerprint analysis in chemically mutagenized Chinese hamster lung cells
1Department of Toxicology, Hita Research Laboratories, Chemicals Inspection and Testing Institute, Ohita, Japan.
Abstract:
Using a multi-locus minisatellite Per-6 DNA probe, we performed DNA fingerprint analysis. Chinese hamster lung (CHL) cells were treated with six model chemicals: N-methyl-N'-nitro-N-nitrosoguanidine, mitomycin C, methyl methanesulfonate, furylfuramide, 2-acetylamino-fluorene, and cyclophosphamide, with or without S9 mix. 771 hypoxanthine phosphoribosyltransferase deficient clones (749 from mutagen-treated cells and 22 from untreated cells) and 90 unselected clones from untreated cells were isolated and analyzed. The spontaneous mutation frequency at CHL cell minisatellite loci was 0.31-0.63%. All the chemicals increased mutation frequencies. Almost all mutations localized to the three specific minisatellite loci corresponding to 4.2, 3.8, and 2.4 kb bands, suggesting that these regions are more unstable and susceptible to mutation. DNA fingerprint analysis is a promising technique for detecting mutations at neutral DNA regions, especially recombinational mutations, and may be useful for surveying genetic instability related to heritable defects or aging.
Insights
DNA fingerprinting revealed that common chemicals significantly increase mutation frequencies in Chinese hamster lung cells. Specific minisatellite regions showed higher instability, indicating their susceptibility to genetic damage.
Area of Science:
- Genetics
- Toxicology
- Molecular Biology
Background:
- Minisatellite DNA regions are prone to mutations.
- Assessing chemical-induced genetic instability is crucial for risk assessment.
Purpose of the Study:
- To evaluate the utility of DNA fingerprinting for detecting chemical-induced mutations.
- To identify specific DNA regions susceptible to mutagenesis in Chinese hamster lung (CHL) cells.
Main Methods:
- DNA fingerprint analysis using a Per-6 minisatellite probe.
- Treatment of CHL cells with six model chemicals (mutagens) +/- S9 mix.
- Isolation and analysis of hypoxanthine phosphoribosyltransferase deficient and unselected clones.
Main Results:
- Spontaneous mutation frequency at minisatellite loci was 0.31-0.63%.
- All tested chemicals elevated mutation frequencies.
- Mutations predominantly occurred at specific minisatellite loci (4.2, 3.8, and 2.4 kb bands).
Conclusions:
- DNA fingerprinting is effective for detecting mutations in neutral DNA regions, particularly recombinational mutations.
- Specific minisatellite loci in CHL cells exhibit heightened instability and susceptibility to mutagens.
- This technique can aid in surveying genetic instability linked to aging and heritable defects.