Transcriptional regulation of the mdm2 oncogene by p53 requires TRRAP acetyltransferase complexes
Transcriptional regulation of the mdm2 oncogene by p53 requires TRRAP acetyltransferase complexes
复制标题
DOI：
10.1128/mcb.22.16.5650-5661.2002
复制
发表时间：
2002-08-01
影响因子：
5.3
通讯作者：
McMahon, SB
中科院分区：
文献类型：
--
作者：
Ard, PG;Chatterjee, C;McMahon, SB
p53肿瘤抑制因子通过其作为序列特异性转录因子的功能调节细胞对遗传损伤的反应。在p53的最充分表征的转录靶点是mdm 2癌基因。mdm 2的激活在p53通路中是至关重要的，因为mdm 2蛋白标记p53蛋白酶体介导的降解，从而提供负反馈回路。在这里，我们表明，ATM相关的TRRAP蛋白功能与p53合作，激活mdm 2转录。TRRAP是涉及转录调节和DNA修复的几种多蛋白乙酰转移酶复合物的组分。在支持这些复合物在mdm 2表达中的作用，我们发现mdm 2基因的反式激活通过药理学抑制细胞脱乙酰酶而增强。体外分析表明，p53直接结合到TRRAP结构域先前被证明是激活剂对接位点。此外，用反义TRRAP转染细胞阻断mdm 2的p53依赖性转录。最后，使用染色质免疫沉淀，我们证明了直接p53依赖的招聘TRRAP的mdm 2启动子，然后增加组蛋白乙酰化。这些发现提示了一种模型，其中p53直接将TRRAP/乙酰转移酶复合物募集到mdm 2基因以激活转录。此外，这项研究定义了一种新的生化机制，利用p53肿瘤抑制基因的表达进行调节。
The p53 tumor suppressor regulates the cellular response to genetic damage through its function as a sequence-specific transcription factor. Among the most well-characterized transcriptional targets of p53 is the mdm2 oncogene. Activation of mdm2 is critical in the p53 pathway because the mdm2 protein marks p53 for proteosome-mediated degradation, thereby providing a negative-feedback loop. Here we show that the ATM-related TRRAP protein functionally cooperates with p53 to activate mdm2 transcription. TRRAP is a component of several multiprotein acetyltransferase complexes implicated in both transcriptional regulation and DNA repair. In support of a role for these complexes in mdm2 expression, we show that transactivation of the mdm2 gene is augmented by pharmacological inhibition of cellular deacetylases. In vitro analysis demonstrates that p53 directly binds to a TRRAP domain previously shown to be an activator docking site. Furthermore, transfection of cells with antisense TRRAP blocks p53-dependent transcription of mdm2. Finally, using chromatin immunoprecipitation, we demonstrate direct p53-dependent recruitment of TRRAP to the mdm2 promoter, followed by increased histone acetylation. These findings suggest a model in which p53 directly recruits a TRRAP/acetyltransferase complex to the mdm2 gene to activate transcription. In addition, this study defines a novel biochemical mechanism utilized by the p53 tumor suppressor to regulate gene expression.