Isolation and characterization of X linked mutants of Drosophila melanogaster which are sensitive to mutagens

Abstract

Thirteen X linked mutants have been isolated in Drosophila melanogaster which render male and homozygous female larvae sensitive to the mutagen methyl methanesulfonate. Their characterization and preliminary assignment to functional groups is described. Four of these mutants are alleles of mei 41. Like previously isolated alleles of this locus, these mutants reduce fertility and increase loss and nondisjunction of the X chromosome in homozygous females. The remaining mutants have been tentatively assigned to 6 functional groups (2 mutants to the mus(1)101 locus, 2 to mus(1)102, 2 to mus(1)103, and 1 each to mus(1)104, mus(1)105, and mus(1)106. Several of the complementation groups can be distinguished on the basis of nondisjunction and cross sensitivity to mutagens. Females homozygous for the mei 41, mus(1)101 and mus(1)102 mutants exhibit elevated levels of nondisjunction. Mutants belonging to complementation groups mei 41, mus(1)101, and mus(1)104 are sensitive to nitrogen mustard (HN2) in addition to their MMS sensitivity. Among these mutants there is currently a direct correlation between sensitivity to HN2, sensitivity to 2 acetylaminofluorene and a deficiency in postreplication repair. Only the mei 41 mutants are hypersensitive to UV radiation, although several of the mutants exhibit sensitivity to γ rays. Semidominance is observed in female larvae of the mei 41, mus(1)104, and mus(1)103 mutants after exposure to high concentrations of MMS. The properties of the mutants generally conform to a pattern which has been established for related mutants in yeast. Additional properties of these mutants are summarized.