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Identification of an overexpressed yeast gene which prevents aminoglycoside toxicity
T R Prezant1, W E Chaltraw, N Fischel-Ghodsian
1Ahmanson Department of Pediatrics, Steven Spielberg Pediatric Research Center, Los Angeles, CA, USA. tPrezant@mailgate.csmc.edu
Abstract:
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.
Insights
Researchers identified a new yeast gene, NEO1, that confers resistance to aminoglycoside antibiotics. This discovery could help understand genetic predispositions to antibiotic-induced hearing loss.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Aminoglycoside antibiotics treat bacterial infections by inhibiting protein synthesis.
- Genetic susceptibility can lead to aminoglycoside-induced sensorineural hearing loss.
- Human hypersensitivity mutations are primarily in the mitochondrial 12S rRNA gene.
Purpose of the Study:
- To identify novel genes predisposing individuals to aminoglycoside hypersensitivity.
- To investigate mechanisms of aminoglycoside antibiotic resistance and interaction.
Main Methods:
- Utilized a yeast model system to screen for genes interacting with or bypassing aminoglycoside effects.
- Isolated a novel gene conferring neomycin resistance in yeast transformants.
- Performed mutagenesis experiments to analyze gene function and drug resistance phenotype.
Main Results:
- Identified and isolated the neomycin-resistance 1 (NEO1) gene.
- NEO1 encodes a putative integral membrane protein homologous to yeast DRS2 (a Ca(2+)-ATPase).
- NEO1 is essential for yeast vegetative growth, and its ATPase function is critical for neomycin resistance.
Conclusions:
- The NEO1 gene product plays a role in cellular processes potentially related to ribosome assembly or function.
- This yeast model provides a new avenue for studying aminoglycoside-antibiotic interactions and genetic hypersensitivity.
- Understanding NEO1's function may offer insights into preventing aminoglycoside-induced hearing loss.