Convergent functions of p53 and BRCA1 in gene regulation

p53 和 BRCA1 在基因调控中的趋同功能

• 批准号: 6563939
• 负责人: Jonathan D. Licht
• 金额: $ 23.8万
• 依托单位: MOUNT SINAI SCHOOL OF MEDICINE OF CUNY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-02-01 至 2003-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6563939
• 关键词: DNA damage; brca gene; cell line; cyclic AMP; gene expression; genetic regulation; genetic transcription; monoclonal antibody; p53 gene /protein; protein protein interaction; tissue /cell culture; transcription factor

The tumor suppressor protein p53 is a transcription factor that has been implicated in the cellular response to DNA damage and mediates either growth arrest or apoptosis. The tumor suppressor BRCA1 is less well- characterized but over-expression of BRCA1 was shown to also alternatively lead to growth arrest or apoptosis p53 and BRCA1 have been shown to interact both physically and functionally. The research proposed in the application is designed to explore the details of p53 and BRCA1-dependent transcriptional activation and elucidate whether the interaction of these tumor suppressor proteins has biological relevance. Preliminary studies have identified two classes of p53 response elements by examining the effect of monoclonal antibody moAb421 on the sequence-specific DNA binding of p53 in electrophoretic mobility shift assays. Incubation with moAb421 enhances the binding of p53 to one set of response elements by inhibits binding to another set, suggesting that different conformations of p53 may interact with each subset of response elements. BRCA1 selectively enhances p53-dependent activation of one subset of sites. Our studies have also shown that the ATF1 transcription factor can interact with BRCA1 protein both physically and functionally and that BRCA1 can augment transcription through a cyclic AMP response element (CRE). Promoters have been identified which contain both a CRE and a p53 binding site. Thus, the proposed aims include experiments to: (1) Determine the significance of distinct subsets of p53 response elements classified by the differential effect of monoclonal antibody moAb421. (2) Determine how BRCA1 alters transcription through the CRE and characterize the interaction of BRCA1 with members of the ATF1 and CREB transcription factors. (3) Characterize the interaction of BRCA1 and p53 on genes that contain both a CRE and a p53 site. (4) Determine the role of BRCA1 and ATF1 in the p53- mediated response to DNA damage. As p53 is mutated in up to 30% of cases of breast cancer and the BRCA1 gene is responsible for approximately 50% of inherited breast cancer, it will be important to determine whether these two tumor suppressor proteins play convergent roles in gene expression involved in the cellular response to DNA damage as well as in the pathogenesis of breast cancer.

肿瘤抑制蛋白p53是一种转录因子，参与细胞对DNA损伤的反应，并介导生长停滞或凋亡。肿瘤抑制因子BRCA 1的特征不太清楚，但BRCA 1的过度表达也显示出可选择地导致生长停滞或凋亡，p53和BRCA 1已经显示出在物理和功能上相互作用。该申请中提出的研究旨在探索p53和BRCA1依赖性转录激活的细节，并阐明这些肿瘤抑制蛋白的相互作用是否具有生物学相关性。初步的研究已经确定了两类p53的反应元件，通过检查单克隆抗体moAb421的影响，在电泳迁移率变动分析的p53的序列特异性DNA结合。与单克隆抗体421孵育通过抑制与另一组反应元件的结合来增强p53与一组反应元件的结合，这表明p53的不同构象可能与反应元件的每个子集相互作用。BRCA1选择性增强一个位点子集的p53依赖性激活。我们的研究还表明，ATF1转录因子可以与BRCA1蛋白在物理和功能上相互作用，BRCA1可以通过环AMP反应元件（CRE）增强转录。已经鉴定了含有CRE和p53结合位点的启动子。因此，所提出的目的包括以下实验：（1）确定通过单克隆抗体moAb421的差异效应分类的p53应答元件的不同子集的意义。(2)确定BRCA1如何通过CRE改变转录，并表征BRCA1与ATF 1和CREB转录因子成员的相互作用。(3)描述BRCA1和p53在含有CRE和p53位点的基因上的相互作用。(4)确定BRCA1和ATF1在p53介导的DNA损伤反应中的作用。由于p53在高达30%的乳腺癌病例中发生突变，而BRCA 1基因导致约50%的遗传性乳腺癌，因此确定这两种肿瘤抑制蛋白是否在涉及对DNA损伤的细胞反应的基因表达中以及在乳腺癌的发病机制中发挥趋同作用将是重要的。