Nuclear protein-induced bending and flexing of the hypoxic response element of the rat vascular endothelial growth factor promoter
Nuclear protein-induced bending and flexing of the hypoxic response element of the rat vascular endothelial growth factor promoter
复制标题
DOI：
10.1096/fj.07-8102com
复制
发表时间：
2008-01-01
期刊：
影响因子：
4.8
通讯作者：
Gillespie, Mark N.
中科院分区：
文献类型：
--
作者：
Breit, Jeffrey F.;Ault-Ziel, Katheryn;Gillespie, Mark N.
DNA的弯曲和挠曲可能有助于转录调节。由于缺氧和其他生理信号诱导在血管内皮生长因子（VEGF）基因的缺氧反应元件（HRE）内的关键碱基处形成脱碱基位点，（FASEB J. 19，387-394，2005），并且因为脱碱基位点可以在模型DNA序列中引入灵活性，在本研究中，我们使用了荧光共振能量转移为基础的报告系统，以评估拓扑结构的变化，在野生型（WT）大鼠VEGF基因的HRE序列和含有模拟缺氧作用的单个脱碱基位点的序列。缺氧诱导的转录复合物中存在的缺氧肺动脉内皮细胞核提取物的WT序列的结合未能改变序列拓扑结构，而核蛋白结合到修改后的HRE产生相当大的序列灵活性。核蛋白对修饰的VEGF HRE的拓扑学效应依赖于转录因子缺氧诱导因子-1和共激活因子Ref-1/Ape 1介导的脱碱基位点处单链断裂的形成。这些观察结果表明，由生理信号引起的VEGF HRE中的氧化碱基修饰可能是单链断裂形成的前体，其通过调节序列灵活性对基因表达产生影响。Breit，J.F.，Ault-Ziel，K.，Al-Mehdi，A. B.，吉莱斯皮，M. N.核蛋白诱导的大鼠血管内皮生长因子启动子缺氧反应元件的弯曲和挠曲。
Bending and flexing of DNA may contribute to transcriptional regulation. Because hypoxia and other physiological signals induce formation of an abasic site at a key base within the hypoxic response element (HRE) of the vascular endothelial growth factor (VEGF) gene (FASEB J. 19, 387-394, 2005) and because abasic sites can introduce flexibility in model DNA sequences, in the present study we used a fluorescence resonance energy transfer-based reporter system to assess topological changes in a wild-type (WT) sequence of the HRE of the rat VEGF gene and in a sequence harboring a single abasic site mimicking the effect of hypoxia. Binding of the hypoxia-inducible transcriptional complex present in hypoxic pulmonary artery endothelial cell nuclear extract to the WT sequence failed to alter sequence topology whereas nuclear protein binding to the modified HRE engendered considerable sequence flexibility. Topological effects of nuclear proteins on the modified VEGF HRE were dependent on the transcription factor hypoxia- inducible factor-1 and on formation of a single-strand break at the abasic site mediated by the coactivator, Ref-1/Ape1. These observations suggest that oxidative base modifications in the VEGF HRE evoked by physiological signals could be a precursor to single-strand break formation that has an impact on gene expression by modulating sequence flexibility.-Breit, J. F., Ault-Ziel, K., Al-Mehdi, A.-B., Gillespie, M. N. Nuclear protein-induced bending and flexing of the hypoxic response element of the rat vascular endothelial growth factor promoter.