Molecular cloning and β-naphthoflavone-induced expression of a cytochrome P450 1A (CYP1A) gene from an anadromous river pufferfish, Takifugu obscurus

摘要

In recent years, there has been a decline in the wild populations of river pufferfish, Takifugu obscurus. Besides overexploitation for commercial purposes, environmental pollution is believed to have contributed to its decline. However, almost no information exists about genes involved in metabolism of xenobiotics by this species. Nevertheless, there is interest in fugu fishes, since they possess the smallest genome among vertebrates. We cloned and characterized the full-length cDNA sequence of a cytochrome P450 1A (CYPIA) gene from T. obscurus. Phylogenic relationship of T. obscurus CYPIA was also compared to other fish species. The tissue distribution and time-dependant induction of CYPIA mRNA were studied by real-time PCR in T. obscurus exposed to an aryl hydrocarbon receptor (Ahr) agonist, β-naphthoflavone (BNF). The greatest basal expression in livers of control as well as BNF-treated individuals. However, brain, gill, gonad, intestine, and kidney also expressed CYPIA. Muscles expressed the least CYPIA. The results of the time-course study revealed induction in brain and gills after 6 h and at 12 h in most tissues. Except for gills, all other organs retained induced expression of CYPIA mRNA up to 96 h.