Identification of an overexpressed yeast gene which prevents aminoglycoside toxicity.

Aminoglycoside antibiotics, used to treat bacterial infections by interfering with proofreading during protein synthesis, cause sensorineural hearing loss in genetically susceptible individuals. The only aminoglycoside-hypersensitivity mutations which have been described in humans are in the mitochondrial 125 rRNA gene, potentially allowing increased antibiotic binding to mitochondrial ribosomes. To identify additional predisposing mutations, a yeast model system was used to isolate genes which interact with or bypass the effects of aminoglycoside antibiotics. A novel yeast gene was isolated which, in high copy, confers neomycin resistance to yeast transformants. The neomycin-resistance 1 gene (NEO1) encodes a potential 1151 as integral membrane protein, most homologous to the yeast DRS2 gene product, a Ca(2+)-ATPase involved in cytoplasmic ribosome assembly. The N-terminus of Neo1p is partially homologous to abrin A-chain, another protein which interacts with cytoplasmic ribosomes. Mutagenesis experiments demonstrate that the NEO1 product is essential for vegetative growth and that the drug-resistance phenotype requires ATPase function.