College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China.
College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China; National Beef Cattle Improvement Center, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Mol Cell Probes. 2019 Dec;48:101443. doi: 10.1016/j.mcp.2019.101443. Epub 2019 Sep 2.
ANGPTL4 (angiopoietin-like 4) is a secreted protein involved in triacylglycerol homeostasis. It is a key enzyme in lipolysis, which stimulates the oxidation of fatty acids and inhibits fat accumulation by inhibiting the activity of lipoprotein lipase (LPL). Using quantitative Real-Time PCR (qRT-PCR) to investigate the mRNA expression pattern of the bovine ANGPTL4 gene in different tissues and organs, we found that bovine ANGPTL4 had the highest expression level in the liver followed by subcutaneous adipose tissue. To clarify the molecular mechanism involved in the regulation of bovine ANGPTL4, we identified the transcriptional start site (TSS) of the ANGPTL4 gene and obtained 2011 bp of the 5' regulatory region. A series of 5' deletion promoter luciferase reporter assays revealed that the minimum functional promoter region of bovine ANGPTL4 was located at -568 bp to -261 bp relative to TSS. Two transcription factors, GR and Foxa1, were identified and considered as important transcriptional activators of ANGPTL4 by mutational analysis and RNA interference assays in combination with electrophoretic mobility shift assays (EMSA) in bovines. In conclusion, GR and Foxa1 were determined to be responsible for the regulation of ANGPTL4 transcription. Our results may provide a basis for further investigation of ANGPTL4 regulation and a reference for improvement of beef quality in cattle.
ANGPTL4（血管生成素样 4）是一种参与三酰甘油稳态的分泌蛋白。它是脂肪分解的关键酶，通过抑制脂蛋白脂肪酶（LPL）的活性来刺激脂肪酸的氧化并抑制脂肪堆积。使用定量实时 PCR（qRT-PCR）研究牛 ANGPTL4 基因在不同组织和器官中的 mRNA 表达模式，我们发现牛 ANGPTL4 在肝脏中的表达水平最高，其次是皮下脂肪组织。为了阐明调节牛 ANGPTL4 的分子机制，我们鉴定了 ANGPTL4 基因的转录起始位点（TSS），并获得了 5'调控区的 2011bp。一系列 5'缺失启动子荧光素酶报告基因检测表明，牛 ANGPTL4 的最小功能启动子区域位于 TSS 上游-568bp 至-261bp。通过突变分析和 RNA 干扰测定以及在牛中的电泳迁移率变动分析（EMSA）结合，鉴定了两个转录因子 GR 和 Foxa1，并认为它们是 ANGPTL4 的重要转录激活因子。总之，GR 和 Foxa1 被确定负责调节 ANGPTL4 转录。我们的研究结果可能为进一步研究 ANGPTL4 的调节提供基础，并为改善牛的牛肉质量提供参考。
