Basal and benzo[a]pyrene-induced expression profile of phase I and II enzymes and ABC transporter mRNA in the early life stage of Chinese rare minnows (Gobiocypris rarus).
ATP-binding cassette (ABC) transporters together with phase I and II detoxification enzymes have been considered as included in a cellular detoxification system. Previous studies have highlighted the involvement of aryl hydrocarbon receptor (AHR) and Cyp1a in PAH-induced embryo toxicity. However, the response of other xenobiotic enzymes/transporters in PAH-mediated embryo toxicity is not fully characterized. In the present study, rare minnow embryos were exposed to 10 and 100µg/L BaP within 4h post-fertilization (hpf) up to 168 hpf. RNA was extracted at 24, 48, 96, and 168 hpf. The basal and BaP-induced expression of phase I enzyme genes (cyp1a, 1b1, and 1c1), phase II enzyme gene (gstm and ugt1a), and ABC transporter genes (abcb1, abcc1, abcc2, and abcg2) mRNA was determined using real-time PCR. Severe developmental defects (e.g., spinal deformities, pericardial and yolk-sac edema) were observed in the BaP treated groups. The basal expression showed that gstm was most strongly expressed, followed by abcb1, ugt1a, and abcc2, whereas cyp1a, 1b1, 1c1, and abcg2 showed weak expression. BaP significantly induced the mRNA expression of three CYP1s (cyp1a, 1b1, and 1c1) (p<0.05) and the ABC transporters (abcc1, abcc2, and abcg2) in a dose-dependent manner. However, the mRNA expression of Phase II enzymes (gstm, ugt1a) for the BaP treatments showed no significant difference with that of the controls. Furthermore, distinct induced patterns of these genes were observed during different exposure periods. Simultaneous up-regulation of the cyp and ABC transporter gene transcripts suggests that a possible involvement and cooperation in the detoxification process could provide protection against the BaP toxicity of rare minnows at the early life stage.
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, PR China; College of Fisheries, Huazhong Agricultural University, Wuhan, China.
Lilai
L
Yuan
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, PR China; College of Fisheries, Huazhong Agricultural University, Wuhan, China.
Biping
B
Lv
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, PR China. Electronic address: jmzha@rcees.ac.cn.
Jinmiao
J
Zha
College of Fisheries, Huazhong Agricultural University, Wuhan, China.
Weimin
W
Wang
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, PR China.
Zijian
Z
Wang
D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000818:Animals; D001564:Benzo(a)pyrene / Q000633:toxicity*; D003530:Cyprinidae / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D019848:Gene Expression Regulation, Archaeal / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics*; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D018528:ATP-Binding Cassette Transporters; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; D014874:Water Pollutants, Chemical; D001564:Benzo(a)pyrene
Embryo toxicity; PAHs; RT-PCR; Xenobiotic enzymes/transporters