College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
Genomics. 2020 May;112(3):2400-2409. doi: 10.1016/j.ygeno.2020.01.012. Epub 2020 Jan 22.
Perilipin 1 (PLIN1) protein, also known as lipid droplet-associated protein, is encoded by the PLIN1 gene and is able to anchor itself to the membranes of lipid droplets. The phosphorylation of PLIN1 is critical for the mobilization of fat in adipose tissue and plays an important role in regulating lipolysis and lipid storage in adipocytes. However, research on the synthesis and lipid metabolism of lipid droplets by PLIN1 in bovine adipocytes is limited. In the present study, we found that bovine PLIN1 was highly expressed in subcutaneous adipose tissue. The highest level of PLIN1 mRNA expression in bovine adipocytes was observed on day 6 of differentiation. Moreover, the cytoplasmic subcellular localization of PLIN1 was observed in bovine preadipocytes. To elucidate the molecular mechanism of bovine PLIN1 transcriptional regulation, we cloned eight fragments containing the 5' regulatory region of the PLIN1 gene. The results showed that the -209/-17 bp region of the bovine PLIN1 gene was the core promoter region. Based on the transcriptional activities of the promoter vector fragments, the luciferase activity of the mutated fragment, the siRNA interference, and the results of the electrophoretic mobility shift assay (EMSA), we identified the binding sites of E2F transcription factor 1 (E2F1), pleiomorphic adenoma gene 1 (PLAG1), CCAAT enhancer binding protein beta (C/EBPβ), and SMAD family member 3 (SMAD3) as the transcriptional activators or repressors of the core promoter region. Further experiments confirmed that the knockdown of the PLIN1 gene affected the ability of these transcription factors to regulate the lipid metabolism in bovine adipocytes. In conclusion, our results reveal a potential mechanism for the transcriptional regulation of PLIN1 in bovine adipocytes.
脂肪滴相关蛋白 1（PLIN1）蛋白，也称为脂滴相关蛋白，由 PLIN1 基因编码，能够锚定在脂滴的膜上。PLIN1 的磷酸化对于脂肪在脂肪组织中的动员至关重要，并在调节脂肪细胞中的脂肪分解和脂质储存中发挥重要作用。然而，关于 PLIN1 在牛脂肪细胞中合成和脂质代谢的研究有限。在本研究中，我们发现牛 PLIN1 在皮下脂肪组织中高度表达。牛脂肪细胞中 PLIN1 mRNA 表达的最高水平出现在分化的第 6 天。此外，在牛前体脂肪细胞中观察到 PLIN1 的细胞质亚细胞定位。为了阐明牛 PLIN1 转录调控的分子机制，我们克隆了包含 PLIN1 基因 5'调控区的 8 个片段。结果表明，牛 PLIN1 基因的-209/-17 bp 区域是核心启动子区域。基于启动子载体片段的转录活性、突变片段的荧光素酶活性、siRNA 干扰和电泳迁移率变动分析（EMSA）的结果，我们确定了 E2F 转录因子 1（E2F1）、多形性腺瘤基因 1（PLAG1）、CCAAT 增强子结合蛋白β（C/EBPβ）和 SMAD 家族成员 3（SMAD3）的结合位点是核心启动子区域的转录激活子或抑制剂。进一步的实验证实，PLIN1 基因的敲低影响了这些转录因子调节牛脂肪细胞中脂质代谢的能力。总之，我们的结果揭示了牛脂肪细胞中 PLIN1 转录调控的潜在机制。
