Up-regulation of hepatic ABCC2, ABCG2, CYP1A1 and GST in multixenobiotic-resistant killifish (Fundulus heteroclitus) from the Sydney Tar Ponds, Nova Scotia, Canada.
Cellular defence against accumulation of toxic xenobiotics includes metabolism by phase I and II enzymes and export of toxicants and their metabolites via ATP-binding cassette (ABC) transporters. Liver gene expression of representatives of these three protein groups was examined in a population of multixenobiotic-resistant killifish (Fundulus heteroclitus) from the Sydney Tar Ponds, Nova Scotia, Canada. The Tar Ponds are heavily polluted with polycyclic aromatic hydrocarbons, polychlorinated biphenyls and heavy metals. The relationship among ABC transporters ABCB1, ABCB11, ABCC2, ABCG2, phase I enzyme cytochrome P4501A1 (CYP1A1) and phase II enzyme glutathione-S-transferase (GST-mu) was investigated by quantifying hepatic transcript abundance. In Tar Pond killifish, hepatic mRNA expression levels of ABCC2, ABCG2, CYP1A1 and GST-mu were elevated compared to reference sites, suggesting that hydrophobic contaminants undergo phase I and II metabolism and are then excreted into the bile of these fish. Hepatic ABCB1 and ABCB11 mRNA were not up-regulated in Tar Pond fish compared to two reference sites, indicating that these two proteins are not involved in conferring multixenobiotic resistance to Tar Pond killifish. The results suggest instead that liver up-regulation of phase I and II enzymes and complementary ABC transporters ABCC2 and ABCG2 may confer contaminant resistance to Tar Pond fish.
Paetzold
S Christine
SC
Biology Department, Dalhousie University, Halifax, Nova Scotia, Canada. paetzold_christine@yahoo.co.uk
Ross
Neil W
NW
Richards
Robert C
RC
Jones
Martha
M
Hellou
Jocelyne
J
Bard
Shannon M
SM
D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics / Q000378:metabolism*; D018432:Drug Resistance, Multiple / Q000235:genetics; D004784:Environmental Monitoring; D023781:Fundulidae / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D019015:Geologic Sediments / Q000032:analysis; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism*; D008658:Inactivation, Metabolic / Q000235:genetics; D008099:Liver / Q000201:enzymology; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism*; D009674:Nova Scotia; D011078:Polychlorinated Biphenyls / Q000378:metabolism; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism; D015854:Up-Regulation; D014874:Water Pollutants, Chemical / Q000378:metabolism; D015262:Xenobiotics / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D019363:Cytochrome P-450 CYP1A1; D005982:Glutathione Transferase; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D011078:Polychlorinated Biphenyls; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D015262:Xenobiotics