Xia Jihan, Hu Bingjun, Mu Yulian, Xin Leilei, Yang Shulin, Li Kui
Key Laboratory for Farm Animal Genetic Resources and Utilization of Ministry of Agriculture of China, Institute of Animal Science (IAS), Chinese Academy of Agricultural Science (CAAS), Beijing, 100193, People's Republic of China,
Mol Biol Rep. 2014 May;41(5):3211-7. doi: 10.1007/s11033-014-3182-x. Epub 2014 Jan 24.
Apolipoprotein E (APOE), a component of lipoproteins plays an important role in the transport and metabolism of cholesterol, and is associated with hyperlipoproteinemia and Alzheimer's disease. In order to further understand the characterization of APOE gene, the promoter of APOE gene of Landrace pigs was analyzed in the present study. The genomic structure and amino acid sequence in pigs were analyzed and found to share high similarity in those of human but low similarity in promoter region. Real-time PCR revealed the APOE gene expression pattern of pigs in diverse tissues. The highest expression level was observed in liver, relatively low expression in other tissues, especially in stomach and muscle. Furthermore, the promoter expressing in Hepa 1-6 was significantly better at driving luciferase expression compared with C2C12 cell. After analysis of porcine APOE gene promoter regions, potential transcription factor binding sites were predicted and two GC signals, a TATA box were indicated. Results of promoter activity analysis indicated that one of potential regulatory elements was located in the region -669 to -259, which was essential for a high expression of the APOE gene. Promoter mutation and deletion analysis further suggested that the C/EBPA binding site within the APOE promoter was responsible for the regulation of APOE transcription. Electrophoretic mobility shift assays also showed the binding site of the transcription factor C/EBPA. This study advances our knowledge of the promoter of the porcine APOE gene.
载脂蛋白E（APOE）是脂蛋白的一个组成部分，在胆固醇的运输和代谢中起重要作用，与高脂蛋白血症和阿尔茨海默病相关。为了进一步了解APOE基因的特征，本研究对长白猪APOE基因的启动子进行了分析。分析了猪的基因组结构和氨基酸序列，发现其与人的基因组结构和氨基酸序列具有高度相似性，但在启动子区域相似性较低。实时荧光定量PCR揭示了猪APOE基因在不同组织中的表达模式。在肝脏中观察到最高表达水平，在其他组织中表达相对较低，尤其是在胃和肌肉中。此外，与C2C12细胞相比，在Hepa 1-6细胞中表达的启动子驱动荧光素酶表达的能力明显更强。在分析猪APOE基因启动子区域后，预测了潜在的转录因子结合位点，并指出了两个GC信号和一个TATA框。启动子活性分析结果表明，其中一个潜在调控元件位于-669至-259区域，这对APOE基因的高表达至关重要。启动子突变和缺失分析进一步表明，APOE启动子内的C/EBPA结合位点负责APOE转录的调控。电泳迁移率变动分析也显示了转录因子C/EBPA的结合位点。本研究增进了我们对猪APOE基因启动子的了解。
