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免受有害变化而避免成为肿瘤。当DNA损伤发生时，肿瘤抑制蛋白P53协调一个复杂的信号通路网络，要么停止细胞周期的进展，试图修复受损的DNA，要么触发细胞死亡。已经观察到，某些危险的DNA损伤形式，如电离辐射引起的双链断裂，会导致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被合理地理解了，但它们在功能上的重要性尚不清楚。这一建议研究了这样一种假设，即P53脉冲对于P53‘S靶基因转录的调节、选择和时间选择是重要的，并且这些表达的变化促进了细胞结果的差异。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验证。一套定制的计算策略将被用来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；以及连续脉冲期间转录因子对p53靶基因的共同调节的差异。差异激活基因、功能通路和P53辅助因子的特定预测将在细胞群体和单个细胞中得到实验证实。这些实验将专门专注于区分正在经历细胞周期停滞、细胞死亡、衰老或对p53脉冲做出反应的DNA修复的细胞。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，了解对P53脉冲的转录反应将进一步加深我们对这种高度通用的转录因子如何在不同的细胞命运决定之间进行选择的理解。这些知识将指导设计改变p53动态的治疗方法，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，这从超过一半的人类癌症包含P53突变的事实中可见一斑。这项建议旨在了解p53的动态如何改变基因表达，并最终控制细胞的命运。了解这种关系将指导设计改变p53动态的治疗方法，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.