微囊藻毒素对鲢鱼肝脏GST和CYP7A1基因表达的影响

为探究微囊藻毒素(MC)对鲢鱼肝脏谷胱甘肽S转移酶(GST)和胆固醇7α-羟化酶(CYP7A1)基因表达的影响,克隆了鲢鱼肝脏GST和CYP7A1基因的部分c DNA片段,并对饲养密度为1.3×108cell/L的有毒和无毒两种铜绿微囊藻水体中第2 d、第4 d和第6 d的鲢鱼肝脏取样,通过RT-PCR与Q-PCR技术分析肝脏GST和CYP7A1基因在MC影响下不同时间点的表达情况。结果显示,有毒铜绿微囊藻水体中鲢鱼肝脏GST相对表达量在第6 d显著下降,说明GST基因在第6 d时在MC解毒过程中开始发挥作用;鲢鱼CYP7A1相对表达量自第2 d开始显著下调并随时间延续维持在一个较低的水平,说明MC作用下CYP7A1表达受到抑制,可能对胆汁酸合成造成影响。为进一步研究鱼类微囊藻毒素去毒基因以及抑制对MC转运和吸收的关键基因提供依据。

Microcystin Effects on the Expression of GST and CYP7A1 Genes in the Liver of Silver Carp

In order to investigate the effect of MC on the expression of GST and CYP7A1 genes, cDNA fragment of GST and CYP7A1 genes was cloned by molecular cloning in this study. Silver carps were fed in water of 2 different Microcystis aeruginosa with 1.3×108 cell/L and liver tissue was got at 2 d, 4 d and 6 d. The expression of GST and CYP7A1 genes in liver under different time points was analyzed by RT-PCR and Q-PCR technology to study the effects of MC on GST and CYP7A1 genes′ expression. The results showed that in the water with toxic Microcystis aeruginosa, relative expression of GST reduced significantly at 6 d, indicating the enablement of this detoxification gene. CYP7A1 relative expression was kept at a low level since 2 d and might impact the bile acid synthesis. This study provided a theoretical basis for further studies on detoxification genes with MC, and a better understanding of the key genes involved in fish by inhibition of MC transfer and absorption.