作　　者： ; ; ; ; ;

机构地区： 暨南大学生命科学技术学院生物工程学系

出　　处： 《热带海洋学报》 2004年第4期49-55,共7页

摘　　要： 从血液提取总DNA并构建基因组文库,克隆海水鱼真鲷(Pagrosomusmajor)脂蛋白脂肪酶(LPL)基因5′侧翼区序列,再通过竞争性聚合酶链式反应(PCR)方法,定量研究饲料中添加不同饱和度脂肪酸对其肝脏LPL基因mRNA表达水平的影响。结果表明,真鲷LPL基因5′侧翼区序列中存在顺式元件过氧化物酶体增殖物反应元件,其序列为TGAAGA TGACAT,与TATA(CATAA)盒序列相隔211bp;与喂饲料对照组比较,添加10%油酸可增加真鲷肝脏LPL基因表达水平,但差异并不显著(p>0.05)。用亚油酸或n 3高不饱和脂肪酸混合物取代添加油酸的一半(占饲料添加量的5%)后,导致真鲷肝脏LPL基因表达水平升高并出现显著性变化(p<0.05)。对真鲷肝脏LPL基因诱导表达随饲料中的脂肪酸不饱和度增加而增加,表明在活体条件下脂肪酸对真鲷肝脏LPL基因表达的诱导作用可能与脂肪酸的氧化代谢有关。n 3高不饱和脂肪酸通过过氧化物酶体增殖物激活受体诱导真鲷肝脏LPL基因表达,使真鲷食物脂质供应水平与其肝脏脂肪酸氧化代谢强度调控偶联起来,可能是真鲷对高脂食物(特别是富含n 3高不饱和脂肪酸食物)的一种适应。 To investigate the cis-acting element and in vivo transcriptional regulation of a marine fish lipoprotein lipase (LPL) gene, 5′-flanking sequence of the gene was cloned from a genomic library, prepared from blood cells of a marine fish, Pagrosomus major, and the effects of dietary fatty acids with different unsaturation degrees on the gene expression of lipoprotein lipase (LPL) in the liver of the fed (5h post-feeding) fish were investigated by a competitive polymerase chain reaction. The sequence with homology to the peroxisome proliferator response element was identified in the 5′-flanking sequence, 211 bp upstream to the TATA box of this LPL gene. After juvenile Pagrosomus major were fed with a commercial diet (diet 1) and diets supplemented with either 10% oleate (diet 2), 5% oleate + 5% linoleate (diet 3) or 5% oleate + 5% n-3 polyunsaturated fatty acid mixture (diet 4) for 4 weeks, the liver LPL mRNA abundance increased per gram tissue by 19.52±6.52 amol (p > 0.05) for diet 2, 37.17±16.56 amol (p < (0.05)) for diet 3, and 40.35±8.70 amol (p < 0.05) for diet 4 respectively in comparison with diet 1 (12.23±3.45 amol). The change of the LPL mRNA level in the liver under feeding conditions of fatty acids was completely consistent with that of fatty acid unsaturation degree, suggesting an involvement of fatty acid oxidation in the stimulation of the liver LPL gene expression. That n-3 polyunsaturated fatty acids modulate the liver LPL gene expression in Pagrosomus major via peroxisome proliferator-activated receptors indicated that the provision of fatty acids to the liver was closely coupled with the oxidation of fatty acids, which might be a physiological adaptation of the fish to high lipid food.

关 键 词： 真鲷 脂蛋白脂肪酶基因 顺式元件 转录调控 高不饱和脂肪酸 肝脏

领　　域： [农业科学]