饥饿及复投喂对金钱鱼肠型脂肪酸结合蛋白基因表达的影响

EFFECTS OF FAST FEEDING AND RE-FEEDING ON THE EXPRESSION OF IFABP IN SCATOPHAGUS ARGUS

  • 摘要: 为阐明肠型脂肪酸结合蛋白基因(ifabp)在金钱鱼(Scatophagus argus)脂肪代谢中的作用, 从金钱鱼肝脏转录组中得到ifabp的unigene片段, 设计特异引物克隆了金钱鱼2种亚型ifabp基因(ssifabp2assifabp2b), 并分析了这2种基因在雌、雄鱼中的组织分布以及饥饿及复投喂后肝脏和肠道中的表达变化。聚类结果表明, ssifabp2a与其他硬骨鱼类Ifabp2a、Ifabp或IfabpX1聚为一类, ssifabp2b则与其他鱼类的Ifabp2b或Ifabp-like聚为一类。同源性比较发现, ssifabp2a与其他硬骨鱼类Ifabp2a、Ifabp或IfabpX1的同源性为78.8%—87.9%; ssifabp2b与其他硬骨鱼类Ifabp2b或Ifabp-like的同源性为79.5%—87.9%; ssifabp2a与ssifabp2b的同源性为73.5%。RT-PCR发现: 在雄鱼中, ssifabp2a在小肠中表达最强, 在肾和肝脏等表达较弱; ssifabp2b也在小肠中表达最强, 在肝脏、胃和下丘脑等较弱。在雌鱼中, ssifabp2a在胃中表达最强, 在肾、肝脏和下丘脑组织表达较弱, 在其他组织中有微弱表达, 脑垂体中没有检测到表达。与ssifabp2a表达情况不同, ssifabp2b在下丘脑、卵巢、心脏、肠中表达较强, 其他组织中有微弱表达, 鳃中没有检测到表达。饥饿及复投喂结果表明: 在肠中, 饥饿2d后, ssifabp2a表达量显著降低, ssifabp2b无显著性变化; 饥饿7d后, ssifabp2a表达量显著下降, 但ssifabp2b无显著性变化; 在复投喂后, 与7d饥饿相比较, ssifabp2assifabp2b的表达量均显著升高。在肝脏中, 饥饿2d后, ssifabp2a表达量无显著变化, 而ssifabp2b的表达量显著升高; 饥饿7d后, ssifabp2assifabp2b的表达量均显著升高; 在复投喂后, ssifabp2a和ssifabp2b表达均显著下降, 恢复到正常水平。结果表明, 饥饿及复投喂对金钱鱼肝脏和肠道中的ssifabp2assifabp2b的表达具有显著影响, 表明两者都参与了金钱鱼的脂肪代谢调节。

     

    Abstract: To elucidate the role of intestinal fatty acid binding protein (Ifabp) in the regulation of lipids metabolism, unigenes were obtained from transcriptome of liver in spotted scat, Scatophagus argus. Two subtypes of ifabp genes (ssifabp2a and ssifabp2b) were isolated and analyzed in the female and male S. argus, respectively. Tissue distributions and changes of ssifabp2a and ssifabp2b in fast feeding and re-feeding were also observed. Phylogenetic tree results showed that ssIfabp2a was clustered with other Ifabp2a, Ifabp or IfabpX1, while ssIifabp2b was clustered with Ifabp2b or Ifabp-like in Osteichthyes. Homology analysis revealed that the sequence identity of ssifabp2a was 78.8%—87.9% with other Osteichthyes Ifabp2a, Ifabp or IfabpX1. The sequence identity of ssifabp2b was 79.5%—87.9% with other Osteichthyes Ifabp2b or Ifabp-like. The sequence identity was 73.5% between ssifabp2a and ssifabp2b. RT-PCR showed that ssifabp2a was the highest in intestine, and had a moderate level in kidney and liver. And ssifabp2b was also the highest in intestine, but had a moderate level in liver, stomach and hypothalamus in male. However, the expression of ssifabp2a was the highest in stomach, and moderate in kidney, liver and hypothalamus, with a weak expression level in other tissues and no expression in pituitary. The ssifabp2b was expressed strongly in hypothalamus, ovary, heart and intestine, and weakly in other tissues, but had no expression in gill of females. In the intestine, the expression of ssifabp2a decreased significantly, but there was no significant change of ssifabp2b after 2d of food deprivation. The expression of ssifabp2a decreased significantly compared with the control group, but there was no significant difference on the expression of ssifabp2b within the 7 day fasting group. The expressions of ssifabp2a and ssifabp2b increased significantly with refeeding 3-h after the scheduled feeding time. In liver, the expression of ssifabp2a was not changed, but the expression of ssifabp2b increased significantly after 2-day of food deprivation. However, the ssifabp2a and ssifabp2b were all increased during the 7-day fasting, and decreased significantly with refeeding 3-h after the scheduled feeding time. In summary, ssIfabp2a and ssIfabp2b are involved in the regulation of lipids metabolism at liver and intestine in Scatophagus argus.

     

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