Hot Spot Analysis of the Breast Cancer Susceptibility Protein

摘要 乳腺癌易感基因（BRCA 1）的生殖系突变与家族性乳腺癌密切相关， 卵巢癌遗传这些突变的女性患这种疾病的可能性约为60%。期间 女性发育正常，脆弱性的关键窗口与乳腺癌的早期发病相关。 这些事件与乳腺组织中DNA损伤的积累相一致，因为活性氧是 由雌激素的代谢过程形成。受损的DNA，如果不修复，可以使错误永久化， 基因组BRCA 1蛋白或BRCA 1突变的表达水平降低， 损伤修复不充分，提供了癌症诱导临界点。在分子水平上， 对这些机制的细节知之甚少。在细胞核中，BRCA 1与其结合伴侣结合 BRCA 1相关环域蛋白（BARD 1），帮助协调DNA修饰的修复。的 BRCA 1-BARD 1异源二聚体通过与其他修复蛋白相互作用来执行这些操作， BRCA 2，在DNA上的受损位点。在这种情况下，BRCA 1作为肿瘤抑制因子，以确保在肿瘤细胞中的保真度。 基因组BRCA 1的遗传突变会导致蛋白质的功能缺陷，从而影响其在以下方面的工作： 肿瘤抑制此外，数十年的科学研究表明，BRCA 1在 DNA修复，关于BRCA 1的物理特性的信息刚刚浮出水面。改善我们 BRCA 1三维（3D）结构的知识可以为治疗发现提供新的见解。在 在拟议的研究中，我们将使用冷冻电子显微镜（EM）成像的独特组合， 技术和生物化学工具来研究野生型和突变型BRCA 1的差异。我们的初步 数据表明，突变的BRCA 1对氧化损伤的反应导致了 蛋白质上的“修饰热点”。我们将在多个乳腺癌细胞系中测试这一想法， 开发一种新的酶方法来减弱癌细胞中的这种效应。我们结合了生物化学和 结构生物学策略将提供一个新的透镜来观察BRCA 1结构的物理细微差别， 第一次这些信息将揭示与癌症易感性相关的BRCA 1缺陷。

Abstract Germline mutations in the breast cancer susceptibility gene (BRCA1) are heavily linked to familial breast and ovarian cancers. Women who inherit these mutations are ~60% more likely to develop the disease. During normal female development, critical windows of vulnerability correlate with the early onset of breast cancer. These events coincide with a buildup of DNA lesions in mammary tissue as reactive oxygen species are formed from the metabolic processing of estrogen. Damaged DNA, if left unrepaired, can perpetuate errors in the genome. Reduced expression levels of the BRCA1 protein or BRCA1 mutations, compounded with insufficient lesion repair, provide a tipping point toward cancer induction. At the molecular level, the intricate details of these mechanisms are poorly understood. In the nucleus, BRCA1 associates with its binding partner the BRCA1-Associated Ring Domain protein (BARD1) to help coordinate the repair of DNA modifications. The BRCA1-BARD1 heterodimer performs these operations by interacting with other repair proteins, such as BRCA2, at damaged sites on DNA. In this context, BRCA1 acts as a tumor suppressor to ensure fidelity in the genome. Inherited mutations in BRCA1 can cause functional deficiencies in the protein that affect its job in tumor suppression. Moreover, as decades of scientific research demonstrate BRCA1's multifaceted role in DNA repair, information about the physical properties of BRCA1 are just coming to light. Improving our knowledge of BRCA1's three-dimensional (3D) structure can provide new insights for therapeutic discovery. In the proposed research, we will use a unique combination of cryo-Electron Microscopy (EM) imaging technology and biochemical tools to study the differences in wild type and mutated BRCA1. Our preliminary data suggests that changes in mutated BRCA1 in response to oxidative damage leads to changes in a “modification hot spot” on the protein. We will test this idea across multiple breast cancer cells lines, then develop a new enzymatic approach to attenuate this effect in cancer cells. Our combined biochemical and structural biology strategies will provide a new lens to view the physical nuances of the BRCA1 structure for the first time. This information will shed light on BRCA1 deficiencies relate to cancer susceptibility.