Stress- and Promoter-Specific Mechanisms of Transcritpional Activation by p53

肿瘤抑制蛋白p53调节基因的表达，这些基因控制细胞对肿瘤的反应。 各种形式的压力。在缺乏p53的情况下，细胞不能启动导致细胞凋亡的转录程序。 周期停滞或凋亡，从而在癌症监视机制中产生缺陷。远景目标 我们的研究重点是了解这些基因是如何被p53和其他因子转录调控的。 以产生对压力最适当的细胞反应并防止肿瘤生长。基于我们 以前的工作中，我们提出p53利用的转录辅因子的集合在不同的 压力类型和不同的靶基因。这项提案的目标是阐明这种情况的分子基础。 组合调节我们的具体目标是： 1.为了阐明p53依赖的转录激活的应激特异性机制， p21/Waf 1/Cip 1基因。p21介导细胞周期阻滞反应，其表达水平变化很大 这取决于压力的来源。我们将确定影响其激活的压力特异性辅助因子。 2.为了确定p53如何在激活后缺乏应激依赖性信号传导的情况下激活转录 关于nutlin Nutlin是一种能够激活p53而不对细胞造成压力的小分子，因此使我们能够 剖析压力依赖信号在p53转录反应中的作用。 3.为了鉴定p53激活凋亡基因p53 A和p53 B的启动子特异性辅因子， Fas/APO1。参与不同细胞途径的p53靶基因受到不同的调节。这表明 不同的辅因子可能对不同基因亚群的激活很重要。 为了实现我们的目标，我们将使用高通量染色质免疫沉淀法来检查 p53和几种辅助因子与p53靶基因在不同形式的应激激活过程中的相互作用。 假定的辅因子在细胞应激反应中的作用将通过干扰其表达来测试。 使用RNAi技术表达。因为大多数抗癌疗法依赖于p53活性来触发肿瘤细胞的凋亡。 我们的研究可能为p53作用模式提供新的见解，并产生新的靶点 用于人类癌症的药物干预。

The tumor supressor protein p53 regulates the expression of genes that control the cellular response to various forms of stress. In the absence of p53, cells fail to initiate transcriptional programs that result in cell cycle arrest or apoptosis,thus generating a defect in the cancer surveillance mechanism. The long-term goal of our research is to understand how these genes are transcriptionally regulated by p53 and other factors in order to produce the most appropiate cellular response to stress and prevent tumor growth. Based on our previous work, we propose that the set of transcriptional co-factors utilized by p53 varies among distinct types of stress and different target genes. The goal of this proposal is to elucidate the molecular basis of this combinatorial regulation. Our specific aims are: 1. To elucidate the stress-specific mechanism of p53-dependent transcriptional activation of the p21/Waf1/Cip1 gene. p21 mediates the cell cycle arrest response and its levels of expression vary greatly depending on the source of stress. We will identify stress-specific co-factors that influence its activation. 2. To determine how p53 activates transcription in the absence of stress-dependent signaling upon activation by nutlin. Nutlin is a small molecule capable of activating p53 without stressing the cells, thus allowing us to dissect the role of stress-dependent signaling in the p53 transcriptional response. 3. To identify promoter-specific co-factors used by p53 to activate the apoptotic genes PUMA and Fas/APO1. p53 target genes involved in diverse cellular pathways are differentially regulated. This suggest that different co-factors may be important for activation of distinct subsets of genes. To achieve our aims we will use high-throughput Chromatin Immunoprecipitation assays to examine the interaction of p53 and several co-factors with p53 target genes during activation by different forms of stress. The role of putative co-factors in the cellular response to stress will be tested by interfering with its expression using RNAi technology. Because most anti-cancer therapies rely on p53 activity to trigger the death of tumor cells, our research may provide new insights in the mode of p53 action and yield new targets for pharmacological intervention in human cancer.