Willett Kristine L, Ganesan Shobana, Patel Monali, Metzger Christine, Quiniou Sylvie, Waldbieser Geoff, Scheffler Brian
Department of Pharmacology and Environmental Toxicology Research Program, University of Mississippi, University, MS 38677, USA.
Mar Environ Res. 2006 Jul;62 Suppl:S332-6. doi: 10.1016/j.marenvres.2006.04.015. Epub 2006 Apr 18.
Our goal was to study the induction of CYP1B mRNA expression in channel catfish (Ictalurus punctatus). CYP1B belongs to the cytochrome P450 superfamily of genes, is involved in the oxidation of endogenous and exogenous compounds, and could potentially be a useful biomarker in fish for exposure to AhR ligands. The full-length catfish CYP1B cDNA is 2417 nt to the polyA tail and encodes a putative protein of 536 amino acids. It has 67% amino acid similarity to carp and zebrafish CYP1B and 68% similarity to carp CYP1B2. Male channel catfish were collected from three Mississippi Delta sites: Lake Roebuck, Itta Bena; Bee Lake, Thornton; and Sunflower River, Indianola. Total RNA was isolated from wild-caught catfish gill, blood, gonad and liver tissues. Quantitative real-time reverse transcriptase PCR was used to determine relative induction of CYP1B in wild catfish compared to laboratory control and BaP-exposed catfish (20mg/kg i.p. after 4 days). BaP exposure significantly induced CYP1B message in blood, gonad, and liver of laboratory catfish. In these same tissues of wild catfish from sites with relatively low sediment contaminants, CYP1B message was not statistically increased relative to laboratory control catfish. CYP1B transcript abundance was higher in gills compared to other tissues in both laboratory and wild catfish. When primary cultured gill cells were treated with increasing concentrations of BaP, TCDD, and PCBs 77, 126 and 169, CYP1B mRNA was induced more than 10-fold while PCB153 and 4,4'DDT did not cause significant CYP1B induction. Our results suggest that catfish CYP1B is induced by the classic AhR ligands.
我们的目标是研究斑点叉尾鮰（Ictalurus punctatus）中CYP1B mRNA表达的诱导情况。CYP1B属于细胞色素P450基因超家族，参与内源性和外源性化合物的氧化，并且可能成为鱼类暴露于芳烃受体（AhR）配体的一种有用生物标志物。斑点叉尾鮰CYP1B cDNA全长至polyA尾为2417 nt，编码一个由536个氨基酸组成的假定蛋白质。它与鲤鱼和斑马鱼的CYP1B氨基酸相似度为67%，与鲤鱼CYP1B2的相似度为68%。雄性斑点叉尾鮰取自密西西比三角洲的三个地点：罗伊巴克湖（位于伊塔贝纳）、比伊湖（位于桑顿）和向日葵河（位于印第安诺拉）。从野生捕获的鲶鱼鳃、血液、性腺和肝脏组织中分离总RNA。使用定量实时逆转录PCR来确定野生鲶鱼中CYP1B相对于实验室对照和经苯并[a]芘（BaP）处理的鲶鱼（腹腔注射20mg/kg，4天后）的相对诱导情况。BaP暴露显著诱导了实验室鲶鱼血液、性腺和肝脏中的CYP1B信息。在来自沉积物污染物相对较低地点的野生鲶鱼的相同组织中，CYP1B信息相对于实验室对照鲶鱼没有统计学上的增加。在实验室鲶鱼和野生鲶鱼中，鳃中的CYP1B转录本丰度均高于其他组织。当原代培养的鳃细胞用浓度不断增加的BaP、2,3,7,8-四氯二苯并-对-二噁英（TCDD）以及多氯联苯77、126和169处理时，CYP1B mRNA被诱导超过10倍，而多氯联苯153和4,4'-滴滴涕（4,4'DDT）并未引起显著的CYP1B诱导。我们的结果表明，鲶鱼CYP1B是由经典的AhR配体诱导的。
