Shenzhen Key Laboratory of Marine Biotechnology and Ecology, Department of Marine Biology, Shenzhen University, Shenzhen 518060, China.
Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
Cells. 2019 May 18;8(5):479. doi: 10.3390/cells8050479.
Changes of Selenoprotein F (SELENOF) protein levels have been reported during selenium supplementation, stressful, and pathological conditions. However, the mechanisms of how these external factors regulate SELENOF gene expression are largely unknown. In this study, HEK293T cells were chosen as an in vitro model. The 5'-flanking regions of SELENOF were analyzed for promoter features. Dual-Glo Luciferase assays were used to detect promoter activities. Putative binding sites of Heat Shock Factor 1 (HSF1) were predicted in silico and the associations were further proved by chromatin immunoprecipitation (ChIP) assay. Selenate and tunicamycin (Tm) treatment were used to induce SELENOF up-regulation. The fold changes in SELENOF expression and other relative proteins were analyzed by Q-PCR and western blot. Our results showed that selenate and Tm treatment up-regulated SELENOF at mRNA and protein levels. SELENOF 5'-flanking regions from -818 to -248 were identified as core positive regulatory element regions. Four putative HSF1 binding sites were predicted in regions from -1430 to -248, and six out of seven primers detected positive results in ChIP assay. HSF1 over-expression and heat shock activation increased the promoter activities, and mRNA and protein levels of SELENOF. Over-expression and knockdown of HSF1 showed transcriptional regulation effects on SELENOF during selenate and Tm treatment. In conclusion, HSF1 was discovered as one of the transcription factors that were associated with SELENOF 5'-flanking regions and mediated the up-regulation of SELENOF during selenate and Tm treatment. Our work has provided experimental data for the molecular mechanism of SELENOF gene regulation, as well as uncovered the involvement of HSF1 in selenotranscriptomic for the first time.
硒蛋白 F(SELENOF)蛋白水平的变化已在硒补充、应激和病理条件下报道过。然而,这些外部因素调节 SELENOF 基因表达的机制在很大程度上是未知的。在本研究中,选择 HEK293T 细胞作为体外模型。分析了 SELENOF 的 5'侧翼区域以研究启动子特征。双荧光素酶检测用于检测启动子活性。通过计算机预测了热休克因子 1(HSF1)的假定结合位点,并通过染色质免疫沉淀(ChIP)实验进一步证明了这些结合。亚硒酸盐和衣霉素(Tm)处理用于诱导 SELENOF 的上调。通过 Q-PCR 和 Western blot 分析 SELENOF 表达和其他相关蛋白的倍数变化。我们的结果表明,亚硒酸盐和 Tm 处理在 mRNA 和蛋白水平上均上调了 SELENOF。鉴定出从-818 到-248 的 SELENOF 5'侧翼区域是核心正调控元件区域。在从-1430 到-248 的区域中预测了四个假定的 HSF1 结合位点,ChIP 实验检测到六个引物中有七个为阳性结果。HSF1 过表达和热休克激活增加了启动子活性以及 SELENOF 的 mRNA 和蛋白水平。在亚硒酸盐和 Tm 处理期间,HSF1 的过表达和敲低对 SELENOF 的转录表现出调节作用。总之,发现 HSF1 是与 SELENOF 5'侧翼区域相关联的转录因子之一,并介导了亚硒酸盐和 Tm 处理期间 SELENOF 的上调。我们的工作为 SELENOF 基因调控的分子机制提供了实验数据,并首次揭示了 HSF1 参与了硒转录组学。