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Sensitivity of drosophila mutants to chemical carcinogens
Abstract:
7 single-mutant and five double-mutant strains of Drosophila melanogaster were tested for their relative sensitivity to the chemical carcinogens: 1-acetylaminofluorene, benzo(alpha)pyrene, N-methyl-N'-nitro-N-nitrosoguanidine, 4-nitro quinoline-1-oxide and aflatoxin B1. Among the single mutants, mei-9a, mei-41D5 and mus(1)104D1 are hypersensitive to all 5 chemicals, whereas mus(1)107D1 is hypersensitive only to 4-nitroquinoline-1-oxide and is slightly sensitive to benzo(alpha)pyrene. The mei-9a mei-41D5 double-mutant is the most sensitive of 5 tested double-mutants which carry the mei-9a allele. When treated with 0.025 mM benzo(alpha)pyrene this double-mutant produces significantly more sex-linked recessive lethals and dominant lethals than does the control. Analysis of double-mutants reveals that the mei-9+ product functions in a different repair pathway of methyl methanesulfonate-induced damage than do the normal products of the mus(1)103, mus(1)104 and mus(1)107 loci. Our findings suggest that the sensitivity of Drosophila repair-deficient mutants could be exploited in screening for potential mutagens and carcinogens.
Insights
Drosophila melanogaster mutants show varying sensitivities to chemical carcinogens. Specific repair-deficient mutants, like mei-9a mei-41D5, are highly sensitive, suggesting their use in mutagen and carcinogen screening.
Area of Science:
- Genetics
- Toxicology
- Molecular Biology
Background:
- Chemical carcinogens pose significant health risks.
- Understanding DNA repair mechanisms is crucial for toxicology.
- Drosophila melanogaster serves as a model organism for genetic studies.
Purpose of the Study:
- To assess the sensitivity of Drosophila melanogaster mutants to various chemical carcinogens.
- To identify specific mutations conferring hypersensitivity to carcinogens.
- To explore the potential of these mutants in mutagen and carcinogen screening.
Main Methods:
- Testing 7 single-mutant and 5 double-mutant Drosophila melanogaster strains.
- Exposure to chemical carcinogens: 1-acetylaminofluorene, benzo(alpha)pyrene, N-methyl-N'-nitro-N-nitrosoguanidine, 4-nitroquinoline-1-oxide, and aflatoxin B1.
- Analysis of sex-linked recessive lethals and dominant lethals.
Main Results:
- Single mutants mei-9a, mei-41D5, and mus(1)104D1 were hypersensitive to all tested carcinogens.
- The mei-9a mei-41D5 double-mutant exhibited the highest sensitivity.
- The mei-9+ gene product functions in a distinct DNA repair pathway compared to mus(1)103, mus(1)104, and mus(1)107.
Conclusions:
- Drosophila melanogaster repair-deficient mutants display differential sensitivities to chemical carcinogens.
- The mei-9a mei-41D5 double-mutant is a highly sensitive indicator for genotoxicity.
- Exploiting these mutants offers a promising approach for screening potential mutagens and carcinogens.