Transcriptional dynamics and cellular function of p53 pulses

描述（由申请人提供）：p53脉冲的转录动力学和细胞功能健康细胞通过保护其DNA免受有害改变而避免成为肿瘤。当DNA损伤发生时，肿瘤抑制蛋白p53协调了一个复杂的信号通路网络，该网络要么阻止细胞周期的进展并试图修复受损的DNA，要么触发细胞死亡。已经观察到某些危险形式的DNA损伤，例如电离辐射引起的双链断裂，导致p53经历一系列波状脉冲。产生这些脉冲的分子机制现在已经得到了合理的理解，但它们的功能重要性尚不清楚。该建议调查的假设，即p53脉冲是重要的调节，选择和定时的转录p53的靶基因，这些变化的表达促进细胞结果的差异。这一假设将通过直接扰动p53脉冲动力学和收集基因表达的时间序列测量来检验。一组定制的计算策略将用于识别由脉冲动力学差异调节的基因组;由脉冲驱动的基因表达变化激活的功能通路;以及在连续脉冲期间p53靶基因的转录因子共调节的差异。差异激活基因，功能通路和p53辅因子的具体预测将在细胞群和单个细胞中实验证实。这些实验将特别集中于区分细胞周期停滞，细胞死亡，衰老或DNA修复响应p53脉冲。由于进入这些细胞状态之一的“决定”在很大程度上是由p53的转录活性决定的，理解对p53脉冲的转录反应将进一步理解这种高度通用的转录因子如何在交替的细胞命运决定之间进行选择。这些知识将指导设计改变p53动力学的治疗方法，以挽救其在阻止肿瘤发展中的适当功能。 公共卫生相关性：p53肿瘤抑制蛋白在预防癌症方面无疑具有重要作用，这反映在超过一半的人类癌症含有p53突变的事实上。该提案旨在了解p53动力学如何改变基因表达并最终控制细胞命运。理解这种关系将指导设计改变p53动力学的治疗方法，以挽救其在阻止肿瘤发展中的适当功能。

DESCRIPTION (provided by applicant): Transcriptional dynamics and cellular function of p53 pulses Healthy cells avoid becoming tumors by protecting their DNA from harmful alterations. When DNA damage occurs, the tumor suppressor protein p53 orchestrates a complex network of signaling pathways that either halts progression through the cell cycle and attempts to repair the damaged DNA, or triggers cellular death. It has been observed that certain dangerous forms of DNA damage, such as double strand breaks caused by ionizing radiation, cause p53 to undergo a series of wave-like pulses. The molecular mechanisms that generate these pulses are now reasonably understood, but their functional importance is not known. This proposal investigates the hypothesis that p53 pulses are important for the regulation, selection and timing of the transcription of p53's target genes and that these changes in expression promote differences in cellular outcome. This hypothesis will be tested by directly perturbing p53 pulse dynamics and collecting time-series measurements of gene expression. A customized set of computational strategies will be used to identify groups of genes that are differentially regulated by pulse dynamics; functional pathways activated by pulse- driven changes in gene expression; and differences in transcription factor coregulation of p53 target genes during successive pulses. Specific predictions of differentially activated genes, functional pathways, and p53 cofactors will be confirmed experimentally in both cell populations and individual cells. These experiments will focus specifically on distinguishing cells that are undergoing cell cycle arrest, cell death, senescence, or DNA repair in response to p53 pulses. Since the "decision" to enter one of these cellular states is largely determined by the transcriptional activity of p53, understanding the transcriptional response to p53 pulses will further our understanding of how this highly versatile transcription factor selects between alternate cell fate decisions. This knowledge will guide the design of therapeutic methods that alter p53 dynamics in order to rescue its proper function in stemming tumor development. PUBLIC HEALTH RELEVANCE: The p53 tumor suppressor protein has an unquestionably important role in guarding against cancer, reflected by the fact that more than half of human cancers contain mutations in p53. This proposal aims to understand how p53 dynamics alter gene expression and ultimately control cell fate. Understanding this relationship will guide the design of therapeutic methods that alter p53 dynamics in order to rescue its proper function in stemming tumor development.