Up-regulation of p300 binding and p50 acetylation in tumor necrosis factor-α-induced cyclooxygenase-2 promoter activation
Up-regulation of p300 binding and p50 acetylation in tumor necrosis factor-α-induced cyclooxygenase-2 promoter activation
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DOI：
10.1074/jbc.m209286200
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发表时间：
2003-02-14
影响因子：
4.8
通讯作者：
Wu, KK
中科院分区：
文献类型：
--
作者：
Deng, WG;Zhu, Y;Wu, KK
p300在基因表达调控中起着重要的作用。然而，目前尚不清楚它的结合是如何受到生理刺激的影响，以及它的结合改变如何影响反式激活蛋白乙酰化。和约束力。在这项研究中，我们通过染色质免疫沉淀和链霉亲和素-琼脂糖下拉试验，在基础和肿瘤坏死因子-a（TNF α）处理的人包皮成纤维细胞中确定了p300与核心环氧化酶-2（考克斯-2）启动子区域的结合。我们发现p300、p50/p65 NF-κ B、.环AMP调节元件结合蛋白-2、CCAAT/增强子结合蛋白β和c-Jun、p50/p65和p300结合被TNF α选择性地增加。免疫沉淀证实了p300与NF-κ B和其他相关的反式激活因子的直接相互作用。在静息细胞中检测到p50乙酰化，并且通过TNF α或脂多糖增加。p300的过表达增强了p50的乙酰化作用，而p50的乙酰化作用通过组蛋白乙酰转移酶结构域的缺失而减弱。增强的p50乙酰化与p50与考克斯-2启动子的结合和转录激活增加相关。E1 A与p300的共转染废除了p50乙酰化和p50结合。这些结果表明，上调p300结合及其乙酰化NF-κ B在考克斯-2启动子激活中占据中心位置。
It is well established that p300 plays an important role in mediating gene expressions. However, it is less clear how its binding is influenced by physiological stimuli and how its altered binding affects transactivator acetylation. and binding. In this study, we determined p300 binding to a core cyclooxygenase-2 (COX-2) promoter region by chromatin immunoprecipitation and streptavidin-agarose pull-down assays in basal and tumor necrosis factor-a (TNFalpha)-treated human foreskin fibroblasts. We found basal binding of p300, p50/p65 NF-kappaB,. cyclic AMP regulatory element-binding protein-2, CCAAT/enhancer-binding protein beta, and c-Jun. p50/p65 and p300 binding was selectively increased by TNFa. Immunoprecipitation confirmed direct interaction of p300 with NF-kappaB and the other involved transactivators. p50 acetylation was detected in resting cells and was increased by TNFalpha or lipopolysaccharide. Overexpression of p300 augmented p50 acetylation, which was attenuated by deletion of its histone acetyltransferase domain. Enhanced p50 acetylation correlated with increased p50 binding to COX-2 promoter and transcriptional activation. Co-transfection of E1A with p300 abrogated p50 acetylation and p50 binding. These findings suggest that up-regulation of p300 binding and its acetylation of NF-kappaB occupies a central position in COX-2 promoter activation.