Tao Hu, Mei Shuqi, Zhang Xuying, Peng Xianwen, Yang Jiahao, Zhu Lihua, Zhou Jiawei, Wu Huayu, Wang Lei, Hua Lun, Li Fenge
Key Laboratory of Pig Genetics and Breeding of Ministry of Agriculture & Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan 430070, PR China.
Hubei Key Laboratory of Animal Embryo Engineering and Molecular Breeding, Hubei Academy of Agriculture Science, Wuhan 430064, PR China.
Int J Biochem Cell Biol. 2014 Feb;47:76-82. doi: 10.1016/j.biocel.2013.12.002. Epub 2013 Dec 13.
The tumor protein 53 (p53) gene played a crucial role in maternal reproduction except its classic roles in maintaining genomic stability and preventing tumorigenesis. However, little is known concerning the regulatory elements which control the expression of p53 gene. In this study, we predicted two binding sites (-490/-477 and -405/-392) of transcription factor CCAAT/enhancer binding protein beta (C/EBPβ) within the core promoter (-985/-273) determined by promoter deletion analysis, and discovered that the second site (-405/-392) was important for p53 promoter activity by site-directed mutagenesis. Then the binding of C/EBPβ to the p53 promoter was identified by electrophoretic mobility shift assays (EMSA) and chromatin immunoprecipitation (ChIP). Moreover, evidence from C/EBPβ overexpression and RNAi studies showed C/EBPβ regulated p53 promoter activity and endogenous p53 expression. Meanwhile, we observed p53 mRNA at the peak in 10(-6)mol/L 17β-estradiol treated cells for 24h via enhancing its core promoter activity. Taken together, our study indicates that C/EBPβ and 17β-estradiol are the essential regulatory factors for p53 transcription.
肿瘤蛋白53（p53）基因除了在维持基因组稳定性和预防肿瘤发生方面发挥经典作用外，在母体生殖过程中也起着关键作用。然而，关于控制p53基因表达的调控元件却知之甚少。在本研究中，我们通过启动子缺失分析预测了转录因子CCAAT/增强子结合蛋白β（C/EBPβ）在核心启动子（-985/-273）内的两个结合位点（-490/-477和-405/-392），并通过定点诱变发现第二个位点（-405/-392）对p53启动子活性很重要。然后通过电泳迁移率变动分析（EMSA）和染色质免疫沉淀（ChIP）鉴定了C/EBPβ与p53启动子的结合。此外，C/EBPβ过表达和RNA干扰研究的证据表明，C/EBPβ调节p53启动子活性和内源性p53表达。同时，我们通过增强其核心启动子活性，观察到在10（-6）mol/L 17β-雌二醇处理24小时的细胞中p53 mRNA达到峰值。综上所述，我们的研究表明C/EBPβ和17β-雌二醇是p53转录的重要调控因子。
