Regulation of inducible nitric oxide synthase expression by p300 and p50 acetylation
Regulation of inducible nitric oxide synthase expression by p300 and p50 acetylation
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DOI：
10.4049/jimmunol.171.12.6581
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发表时间：
2003-12-15
影响因子：
4.4
通讯作者：
Wu, KK
中科院分区：
文献类型：
--
作者：
Deng, WG;Wu, KK
为了确定p300是否参与诱导型一氧化氮合酶（iNOS）的转录调控，我们评估了p300过表达对iNOS表达的影响，并在RAW 264.7细胞中表征了p300与iNOS启动子的结合。p300过表达增加iNOS表达，而组蛋白乙酰转移酶（HAT）结构域（Delta 1472 -1522）的缺失可消除iNOS表达。DNA结合和染色质免疫沉淀试验表明，p300结合到几个DNA结合的反式激活因子在基础状态。用LPS加IFN-γ刺激后，p300、p50/p65 NF-icB和IFN-调节因子-1的结合增加了约2倍。核p50与p300在基础结合状态下复合并被其乙酰化，所述基础结合状态通过LPS和IFN-γ刺激而增加。p300过表达导致p50乙酰化水平升高，而HAT突变则降低了乙酰化水平。p50乙酰化与增加的NF-κ B结合和增强的p300募集相关。E1 A的共过表达消除了p300过表达诱导的p50乙酰化和p50结合的增强，以及p300募集到复合物的相关抑制。我们的结论是，p300是必不可少的iNOS转录。我们的研究结果表明，p300 HAT乙酰化NF-κ B的p50亚基，从而增加NF-κ B结合和NF-κ B介导的反式激活。
To determine whether p300 is involved in inducible NO synthase (iNOS) transcriptional regulation, we evaluated the effect of p300 overexpression on iNOS expression and characterized p300 binding to iNOS promoter in RAW 264.7 cells. p300 overexpression increased iNOS expression which was abrogated by deletion of the histone acetyltransferase (HAT) domain (Delta1472-1522). DNA-binding and chromatin immunoprecipitation assays revealed binding of p300 to several DNA-bound transactivators at basal state. Following stimulation with LPS plus IFN-gamma, binding of p300, p50/p65 NF-icB, and IFN-regulatory factor-1 was increased by similar to2-fold. Nuclear p50 was complexed with and acetylated by p300 at the basal binding state which was increased by LPS and IFN-gamma stimulation. p300 overexpression resulted in increased p50 acetylation which was reduced by HAT mutation. p50 acetylation correlated with increased NF-kappaB binding and enhanced p300 recruitment. Co-overexpression of E1A abolished the augmentation of p50 acetylation and p50 binding induced by p300 overexpression, and a correlative suppression of p300 recruitment to the complex. We conclude that p300 is essential for iNOS transcription. Our results suggest that p300 HAT acetylates the p50 subunit of NF-kappaB, thereby increasing NF-kappaB binding and NF-kappaB mediated transactivation.