Characterization of Saccharomyces cerevisiae mutants supersensitive to aminoglycoside antibiotics.

We describe mutants of Saccharomyces cerevisiae that are more sensitive than the wild type to the aminoglycoside antibiotics G418, hygromycin B, destomycin A, and gentamicin X2. In addition, the mutants are sensitive to apramycin, kanamycin B, lividomycin A, neamine, neomycin, paromomycin, and tobramycin--antibiotics which do not inhibit wild-type strains. Mapping studies suggest that supersensitivity is caused by mutations in at least three genes, denoted AGS1, AGS2, and AGS3 (for aminoglycoside antibiotic sensitivity). Mutations in all three genes are required for highest antibiotic sensitivity; ags1 ags2 double mutants have intermediate antibiotic sensitivity. AGS1 was mapped 8 centimorgans distal from LEU2 on chromosome III. Analyses of yeast strains transformed with vectors carrying antibiotic resistance genes revealed that G418, gentamicin X2, kanamycin B, lividomycin A, neamine, and paromomycin are inactivated by the Tn903 phosphotransferase and that destomycin A is inactivated by the hygromycin B phosphotransferase. ags strains are improved host strains for vectors carrying the phosphotransferase genes because a wide spectrum of aminoglycoside antibiotics can be used to select for plasmid maintenance.