Mutations of the withered (whd) gene in Drosophila melanogaster confer hypersensitivity to oxidative stress and are lesions of the carnitine palmitoyltransferase I (CPT I) gene.
Since some oxygen defense mutants of Drosophila melanogaster exhibit a crinkled wing phenotype, a screen was performed on strains bearing mutant alleles conferring a visible wing phenotype to determine whether any were hypersensitive to oxidative stress. One mutant, withered (whd), was found to be sensitive to both dietary paraquat and hyperoxia. New alleles of whd were induced on a defined genetic background and strains carrying these alleles were also found to be sensitive to oxidative stress. To identify the product of the whd gene we used a sequence-based positional candidate approach and by this method we determined that whd encodes carnitine palmitoyltransferase I (CPT I), an enzyme of the outer mitochondrial membrane that is required for the import of long-chain fatty acids into the mitochondria for beta-oxidation. Although this function is not vital under laboratory conditions, whd adults were found to be highly sensitive to starvation and to heavy metal toxicity relative to controls. This work uncovers a novel relationship between fatty acid metabolism and reactive oxygen metabolism. Further, these results in conjunction with past research on whd and on mammalian CPT I support the hypothesis that CPT I serves a vital function in the response to thymine supplementation.
Strub
Benjamin R
BR
Department of Biology, York University, 4700 Keele Street, Toronto, ON M3J1P3, Canada.
Parkes
Tony L
TL
Mukai
Spencer T
ST
Bahadorani
Sepehr
S
Coulthard
Alistair B
AB
Hall
Nichole
N
Phillips
John P
JP
Hilliker
Arthur J
AJ
D000818:Animals; D030801:Animals, Genetically Modified; D002334:Carnitine O-Palmitoyltransferase / Q000235:genetics*; D002874:Chromosome Mapping; D029721:Drosophila Proteins / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D004342:Drug Hypersensitivity; D005260:Female; D005720:Gamma Rays; D018496:Hyperoxia / Q000150:complications; D007814:Larva / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects; D008297:Male; D019216:Metals, Heavy / Q000633:toxicity; D009154:Mutation / Q000235:genetics*; D018384:Oxidative Stress; D010269:Paraquat / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D014921:Wings, Animal / Q000166:cytology / Q000378:metabolism
D029721:Drosophila Proteins; D019216:Metals, Heavy; D002334:Carnitine O-Palmitoyltransferase; D010269:Paraquat