Transgenic Drosophila carrying mammalian cytochrome P-4501A1: an application to toxicology testing.
Transgenic Drosophila which carry a canine cytochrome P-450 were established and evaluated for its value on toxicology testing. Dah1, a cDNA clone for the canine hepatic P-4501A1, was ligated between the promoter of Drosophila heat-shock protein gene and the terminator of actin 5C gene, and then microinjected into Drosophila embryos with a transposon P element. The injected DNA was stably integrated into chromosomal DNA in germ line cells. After heat-shock treatments, transgenic larvae produced mRNA and a detectable amount of protein that cross-reacted with antibodies against rat P-4501A1. The ability of transgenic flies to activate procarcinogens was monitored in the DNA repair test with the endpoint being preadult mortality of repair-defective mei-9a mei-41D5/Y males. Heat-shock treatments of larvae showed that the repair-defective males carrying the P-4501A1 transgene were killed by lower concentrations of 7,12-dimethylbenz[a]anthracene than their non-transgenic or non heat-shocked counterparts. Coadministration of alpha-naphthoflavone, one of the inhibitors of P-4501A subfamily, cancelled the enhanced mortality of transgenic males, supporting that 7,12-dimethylbenz[a]anthracene was metabolized to its genotoxic form by the expressed P-4501A1 enzyme. This study indicates a potential utility of transgenic Drosophila for screening mammalian promutagens and procarcinogens.
Komori
M
M
Division of Drug Metabolism, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Kitamura
R
R
Fukuta
H
H
Inoue
H
H
Baba
H
H
Yoshikawa
K
K
Kamataki
T
T
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000493:pharmacokinetics / Q000633:toxicity; D000818:Animals; D030801:Animals, Genetically Modified; D001711:Biotransformation; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000235:genetics; D004249:DNA Damage / Q000502:physiology; D004260:DNA Repair / Q000502:physiology; D004285:Dogs; D004330:Drosophila / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000235:genetics; D006358:Hot Temperature; D007527:Isoenzymes / Q000235:genetics*; D008297:Male; D010375:Pedigree; D014116:Toxicology / Q000379:methods*
D007527:Isoenzymes; D015127:9,10-Dimethyl-1,2-benzanthracene; D004247:DNA; D003577:Cytochrome P-450 Enzyme System