淡水鱼类微囊藻毒素去毒酶基因的克隆

微囊藻毒素去毒酶在鱼类微囊藻毒素去毒过程中起着关键作用,研究成功克隆鲢鱼、鳙鱼、草鱼、鲫鱼、鳜鱼、罗非鱼等淡水鱼类微囊藻毒素去毒酶基因cDNA核心片段而首次获得这些淡水鱼类微囊藻毒素去毒酶氨基酸序列。鲢鱼、鳙鱼、草鱼、鲫鱼、鳜鱼、罗非鱼微囊藻毒素去毒酶基因与人、小鼠、大鼠、牛、猪、羊的谷胱甘肽S-转移酶基因氨基酸同源性为60%左右,表明淡水鱼类微囊藻毒素去毒酶基因在进化上变异性较大,与其承担微囊藻毒素去毒代谢之特殊功能相适应。

Cloning of the microcystin-detoxifizyme gene in the main Chinese freshwater fishes

Microsystin-detoxifizyme gene plays an important role in microcystin detoxication in freshwater fishes. cDNA fragments that encoding partial sequences of microsystin-detoxifizyme gene were successfully amplified by RT-PCR using degenerate primers from the liver of the main Chinese freshwater fishes, including silver carp, bighead carp, grass carp, goldfish, Chinese perch and Tilapia. Homologous analysis show that the deduced amino acid sequences of the microsystin-detoxifizyme gene in silver carp, bighead carp, grass carp, goldfish, Chinese perch and Tilapia were ~50%-60% homologus to the glutathione S-transferase gene of mammals, such as human, mouse, rat, cow, pig and sheep. The homologous analysis results indicate a big difference between the microcystin-detoxifizyme gene of freshwater fishes and the glutathione S-transferase gene of mammals, which may explain the special function of this gene in freshwater fishes for microcystin detoxication.