The Role of p53 and 14-3-3 in Genomic Instability

p53 和 14-3-3 在基因组不稳定性中的作用

• 批准号: 7033879
• 负责人: JESSE D. MARTINEZ
• 金额: $ 27.18万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7033879
• 关键词: DNA replication; Drosophilidae; cell cycle proteins; cell growth regulation; chromatin immunoprecipitation; cyclin dependent kinase; functional /structural genomics; gene duplication; genetically modified animals; human tissue; immunocytochemistry; lung neoplasms; mutant; neoplasm /cancer genetics; p53 gene /protein; protein isoforms; protein protein interaction; protein structure function; western blottings

DESCRIPTION (provided by applicant): Genomic instability is a hallmark of cancer and an enabling feature that facilitates tumor development and advancement to malignancy. The p53 tumor suppressor is known to play a major role in the stabilization of the genome. However, the mechanism by which p53 executes it's function as "guardian of the genome" is unclear. In preliminary studies we have determined that 14-3-3gamma, a protein known to interact with the p53 tumor suppressor, can cause a form of genomic instability that is manifested by endoreduplication and production of cells with > 4N DNA content. We have found that this activity occurs in cells that lack a functional p53, but does not occur in cells where p53 remains active. Because polyploidy is an unstable condition that precedes aneuploidy, we postulate that 14-3-3gamma may decrease genomic stability when present at elevated levels. In support of this it has been reported that 14-3-3 expression is elevated in lung cancer and our preliminary data indicates that 14-3-3gamma is one of the isoforms that is overexpressed in these tumors. Because 14-3-3gamma physically interacts with the p53 protein and because the 14-3-3gamma-mediated rereplication phenotype occurs in the absence of a functional p53 we hypothesize that p53 suppresses 14-3-3gamma's ability to cause genomic instability through a direct physical interaction between the two proteins. To test this we will determine 1) whether 14-3-3gamma causes endoreduplication by examining its affect on the function of cell cycle control proteins, initiation of DNA replication, and cell cycle checkpoints, 2) whether wild-type p53 can suppress the endoreduplication and whether this requires a direct physical interaction with 14-3-3gamma and 3) characterize 14-3-3 expression in human lung tumors.

描述（由申请人提供）：基因组不稳定性是癌症的标志，也是促进肿瘤发展和进展为恶性肿瘤的有利特征。已知p53肿瘤抑制因子在基因组的稳定中起主要作用。然而，p53执行其“基因组监护人”功能的机制尚不清楚。在初步研究中，我们已经确定14-3-3gamma，一种已知与p53肿瘤抑制因子相互作用的蛋白质，可以引起一种形式的基因组不稳定性，表现为核内复制和产生具有> 4 N DNA含量的细胞。我们已经发现，这种活性发生在缺乏功能性p53的细胞中，但不发生在p53保持活性的细胞中。由于多倍性是一种不稳定的条件，非整倍性之前，我们假设，14-3- 3 γ可能会降低基因组的稳定性时，在升高的水平。为了支持这一点，据报道，14-3-3表达在肺癌中升高，我们的初步数据表明，14-3- 3 γ是在这些肿瘤中过表达的同种型之一。由于14-3- 3 γ与p53蛋白的物理相互作用，并且由于14-3- 3 γ介导的再复制表型在功能性p53不存在的情况下发生，我们假设p53通过两种蛋白之间的直接物理相互作用抑制14-3- 3 γ引起基因组不稳定的能力。为了测试这一点，我们将确定1）通过检查14-3- 3 γ对细胞周期控制蛋白的功能、DNA复制的起始和细胞周期检查点的影响，14-3- 3 γ是否引起核内复制，2）野生型p53是否可以抑制核内复制，以及这是否需要与14-3- 3 γ的直接物理相互作用和3）表征14-3-3在人肺肿瘤中的表达。