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Isolation of overexpressed yeast genes which prevent aminoglycoside toxicity
D F Johnson1, T R Prezant, B Lubavin
1Ahmanson Department of Pediatrics, Steven Spielberg Pediatric Research Center, The Cedars-Sinai Medical Center Burns and Allen Research Institute and UCLA School of Medicine, Los Angeles, CA 90048, USA.
Abstract:
Aminoglycoside antibiotics at non-toxic levels can cause sensorineural hearing loss in genetically predisposed individuals. The major aminoglycoside hypersensitivity mutation that has been described in humans is at position 1555 in the mitochondrial 12S ribosomal RNA gene. In order to identify additional candidate genes for genetic susceptibility mutations in humans and possibly develop therapeutic interventions, we are using yeast as a model organism to identify genes whose products interact with aminoglycosides or bypass the effects of aminoglycoside poisoning. We have selected yeast genomic DNAs that, when cloned into a high copy number plasmid, confer neomycin resistance. We have previously described the first gene identified through this approach [Prezant, Chaltraw and Fischel-Ghodsian, Microbiology 142 (1996) 3407 3414] and have now completed this search by the exhaustive screening of 35 yeast genome equivalents. This has resulted in the identification of seven additional chromosomal regions. All seven chromosomal regions have been characterized and the most likely gene responsible for aminoglycoside resistance has been identified for each of them. While the mechanism of aminoglycoside resistance can be inferred for some of the gene products, it remains to be determined for others.
Insights
Researchers used yeast to find genes linked to aminoglycoside antibiotic resistance, identifying seven new genetic regions. This research may help understand genetic susceptibility to hearing loss and develop new therapies.
Area of Science:
- Genetics
- Microbiology
- Pharmacology
Background:
- Aminoglycoside antibiotics can cause hearing loss in susceptible individuals.
- A known mutation at position 1555 in the mitochondrial 12S ribosomal RNA gene is linked to this hypersensitivity.
- Identifying additional genetic factors is crucial for understanding susceptibility and developing interventions.
Purpose of the Study:
- To identify novel genes conferring genetic susceptibility to aminoglycoside-induced hearing loss.
- To utilize yeast as a model organism for discovering genes interacting with aminoglycosides.
- To explore potential therapeutic targets for aminoglycoside poisoning.
Main Methods:
- Yeast genomic DNA was screened for genes conferring neomycin resistance when cloned into high copy number plasmids.
- An exhaustive screening of 35 yeast genome equivalents was performed.
- Identified chromosomal regions were characterized to pinpoint responsible genes.
Main Results:
- Seven additional chromosomal regions conferring aminoglycoside resistance were identified.
- The most likely gene responsible for resistance was identified in each of the seven regions.
- The mechanisms of resistance for some identified gene products were inferred, while others require further investigation.
Conclusions:
- This study successfully identified new candidate genes associated with aminoglycoside resistance using a yeast model.
- The findings expand the understanding of genetic factors influencing aminoglycoside hypersensitivity.
- Further research is needed to elucidate the resistance mechanisms for all identified gene products and their therapeutic implications.