Kim Hyesoon, Lee Seung-Hwan, Lee Mi-Ni, Oh Goo Taeg, Choi Kyung-Chul, Choi Eun Young
Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul, Republic of Korea.
Oncotarget. 2013 Nov;4(11):1976-85. doi: 10.18632/oncotarget.1318.
Developmental endothelial locus-1 (Del-1) is an endothelium-derived anti-inflammatory molecule that is downregulated by inflammatory stimuli. Little is known about the molecular mechanisms by which Del-1 transcription is regulated. In the present study, a DNA sequence upstream of the Del-1 gene was analyzed and putative p53 response elements (p53REs) were identified. An approximately 2 kb fragment upstream of the translation start site displayed the highest Del-1 transcriptional activity, and the transcriptional activity of this fragment was enhanced by overexpression of p53. Chemical activation of endogenous p53 elevated the levels of Del-1 mRNA. Site-directed mutagenesis of CATG in the consensus sequences of the 2 kb fragment to TATA significantly reduced the transcription of Del-1. Chromatin immunoprecipitation revealed recruitment of p53 to the p53REs of the Del-1 promoter, resulting in increased Del-1 transcription. Finally, primary endothelial cells isolated from mice with reduced levels of p53 showed a decrease in Del-1 mRNA compared to wild-type endothelial cells. Moreover, Del-1 reciprocally enhanced p53 expression in primary endothelial cells. Thus, these findings suggest that Del-1 is a novel transcriptional target gene of p53.
发育性内皮位点-1（Del-1）是一种内皮细胞衍生的抗炎分子，其表达受炎症刺激下调。目前对于Del-1转录调控的分子机制知之甚少。在本研究中，对Del-1基因上游的DNA序列进行了分析，并鉴定出了假定的p53反应元件（p53REs）。翻译起始位点上游约2 kb的片段表现出最高的Del-1转录活性，并且该片段的转录活性通过p53的过表达而增强。内源性p53的化学激活提高了Del-1 mRNA的水平。将2 kb片段共有序列中的CATG定点突变为TATA，显著降低了Del-1的转录。染色质免疫沉淀显示p53被招募到Del-1启动子的p53REs上，从而导致Del-1转录增加。最后，与野生型内皮细胞相比，从p53水平降低的小鼠中分离出的原代内皮细胞中Del-1 mRNA水平降低。此外，Del-1在原代内皮细胞中可相互增强p53的表达。因此，这些发现表明Del-1是p53的一个新的转录靶基因。
