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.