Cytochrome P4501A (CYP1A) has been used as a specific biomarker for monitoring water contamination such as PAHs, PCBs and dioxins. In the present study, the cyp1a gene of Gambusia affinis was cloned and sequenced and their expressions under PAHs exposure were characterized. The newly identified cyp1a encodes a protein with 521 amino acids that shared 96–80% identity with other Cyprinodontiformes fishes. RT-PCR analysis revealed that the basal mRNA level of cyp1a was highly expressed in liver and intestine. The expression level of cyp1a was significantly induced by exposure to 100 μg/L 3, 4-Benzopyrene (BaP) for 5 days in the muscle, testis, brain, liver and intestine of adult male fish. Except in the testis, the induced mRNA level of cyp1a ultimately decreased after prolonging the exposure time to 25 days. As for testis, the induced mRNA level of cyp1a was maintained at a high level during the entire exposure time under 100 μg/L BaP exposure. Furthermore, the expression of cyp1a increased with exposure time under a relatively low exposure concentrations 1 μg/L. Regarding the effects of other PAHs, D(a,h)A, BbF, and BaA showed a statistically significant effect of induction on mRNA level of cyp1a in the muscle, testis, brain, liver and intestine.

中文翻译：

---

牙龈肌中的细胞色素P450 1A mRNA及其对几种PAH的反应。

细胞色素P4501A（CYP1A）已用作监测PAH，PCB和二恶英等水污染的特定生物标志物。在本研究中，CYP1A的基因食蚊被克隆和测序及其多环芳烃曝光下表达进行表征。新鉴定的cyp1a编码一种具有521个氨基酸的蛋白质，与其他犬齿类鱼类共有96-80％的同一性。RT-PCR分析显示cyp1a的基础mRNA水平在肝和肠中高表达。cyp1a的表达水平在成年雄性鱼类的肌肉，睾丸，脑，肝和肠中，暴露于100μg/ L 3，4-苯并yr（BaP）5天，可显着诱导其被诱导。除了在睾丸中，将暴露时间延长至25天后，cyp1a的诱导mRNA水平最终下降。至于睾丸，在整个暴露时间内，在100μg/ L BaP暴露下，cyp1a的诱导mRNA水平保持较高水平。此外，在相对低的暴露浓度1μg/ L下，cyp1a的表达随暴露时间的延长而增加。关于其他PAHs的影响，D（a，h）A，BbF和BaA对肌肉，睾丸，脑，肝和肠中cyp1a的mRNA表达具有统计学意义的诱导作用。