Humanized Mouse Models for the p53 R72P SNP

描述(由申请人提供)：由于遗传等其他因素，暴露在相同环境因素下的个人往往会有不同的反应。因此，确定人类序列变异(多态)如何影响对环境暴露的反应是理解疾病易感性的个体差异的关键。人类P53基因在许多细胞应激反应中起着关键作用，它包含一种常见的多态，导致P53蛋白第72位的精氨酸(R)或脯氨酸(P)残基。大量的流行病学研究已经将这种多态与患各种癌症和其他疾病的风险联系起来。然而，不同的基因类型与患不同癌症的易感性有关，在某些情况下，存在相互矛盾的数据。一些实验室研究表明，这两个p53变异体激活某些靶基因的能力不同，而另一些研究表明，这两个变异体通过转录非依赖机制诱导细胞凋亡的能力不同。此外，这种多态可能影响突变型P53的功能获得能力。解释这些功能研究的一个主要问题是，所有这些研究都是在人工体外条件下完成的，因此迫切需要以一种更具生理学相关性的方式对R72P多态进行建模。这一应用是基于这样一个假设，即人类P53 R72P多态可以在小鼠身上建模，并且这些模型可以成为基础研究和翻译研究的重要工具。已经建立了小鼠模型来研究特定突变和修饰位置对P53的作用，但还没有建立小鼠模型来研究R72P多态。这可能是因为72位氨基酸位于人类P53的一个区域，该区域与小鼠的P53缺乏同源性。为了解决这个问题，我们使用了两种不同的方法来开发P53R72P多态的人源化小鼠模型。本申请中提出的实验将验证这些小鼠模型，重点是确定R72P多态如何调控细胞凋亡和皮肤癌的发展。这项建议的长期目标是使用这些小鼠模型研究的数据来开发和测试关于这种P53基因多态在人类健康和疾病中的作用的新假说。公共卫生相关性：确定人类基因组的微小变异(多态)如何影响对环境暴露的反应，是了解疾病易感性的个体差异的关键。流行病学研究表明，人类P53基因的单核苷酸多态(SNP)会影响个体患各种癌症的几率，但其潜在机制尚不清楚。这项建议寻求使用新的小鼠模型来研究这种常见的P53 SNP如何调节人类癌症和其他环境相关疾病的发展。

DESCRIPTION (provided by applicant): Individuals exposed to the same environmental agent often respond differently due to additional factors such as genetics. Therefore, determining how human sequence variations (polymorphisms) influence the response to environmental exposures is key to understanding individual variability in disease susceptibility. The human p53 gene, which plays a critical role in the response to many cellular stresses, contains a common polymorphism that results in either an arginine (R) or proline (P) residue at position 72 of the p53 protein. Numerous epidemiological studies have associated this polymorphism with risk for developing various cancers and other diseases. However, different genotypes are associated with a predisposition for developing different cancers and in some cases there is conflicting data. Some laboratory studies suggest that the two p53 variants differ in their abilities to activate certain target genes while other studies suggest that the variants differ in their ability to induce apoptosis through a transcription-independent mechanism. Moreover, this polymorphism may affect the gain-of-function ability of mutant p53. A major problem with the interpretation of these functional studies is that all were done using artificial in vitro conditions and thus there is a critical need to model the R72P polymorphism in a way that is more physiologically relevant. This application is based on the hypothesis that the human p53 R72P polymorphism can be modeled in the mouse and that these models can be important tools for basic and translational research. Mouse models have been developed to study the role of specific mutations and sites of modification on p53, but no mouse model has been developed to study the R72P polymorphism. This may be because amino acid 72 is located in a region of human p53 that lacks homology to murine p53. To overcome this problem, we have used two different approaches to develop "humanized" mouse models for the p53 R72P polymorphism. Experiments proposed in this application will validate these mouse models with a focus on determining how the R72P polymorphism modulates apoptosis and skin cancer development. The long-term objective of this proposal is to use data from these mouse model studies to develop and test new hypothesis on the role of this p53 polymorphism in human health and disease. PUBLIC HEALTH RELEVANCE: Determining how small variations in the human genome (polymorphisms) influence the response to environmental exposures is key to understanding individual variability in disease susceptibility. Epidemiological studies suggest that a single nucleotide polymorphism (SNP) in the human p53 gene affects an individual's chances of developing various cancers but the underlying mechanism for this is not understood. This proposal seeks to use novel mouse models to study how this common p53 SNP modulates the development of human cancer and other environmentally related diseases.