Recent advances in the development of functional materials offer new tools to dissect human health and disease mechanisms. The use of tunable surfaces is especially appealing as substrates can be tailored to fit applications involving specific cell types or tissues. Here we use tunable materials to facilitate the three-dimensional (3D) analysis of BRCA1 gene regulatory complexes derived from human cancer cells. We employed a recently developed microchip platform to isolate BRCA1 protein assemblies natively formed in breast cancer cells with and without BRCA1 mutations. The captured assemblies proved amenable to cryo-electron microscopy (EM) imaging and downstream computational analysis. Resulting 3D structures reveal the manner in which wild-type BRCA1 engages the RNA polymerase II (RNAP II) core complex that contained K63-linked ubiquitin moieties-a putative signal for DNA repair. Importantly, we also determined that molecular assemblies harboring the BRCA15382insC mutation exhibited altered protein interactions and ubiquitination patterns compared to wild-type complexes. Overall, our analyses proved optimal for developing new structural oncology applications involving patient-derived cancer cells, while expanding our knowledge of BRCA1's role in gene regulatory events.

中文翻译：

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用于结构肿瘤学应用的微芯片平台。

功能材料开发的最新进展为剖析人类健康和疾病机制提供了新的工具。可调表面的使用特别吸引人，因为可以定制基板以适合涉及特定细胞类型或组织的应用。在这里，我们使用可调材料来促进对源自人类癌细胞的BRCA1基因调控复合物的三维（3D）分析。我们采用了最近开发的微芯片平台来分离在具有和不具有BRCA1突变的乳腺癌细胞中天然形成的BRCA1蛋白组装体。事实证明，捕获的组件适用于低温电子显微镜（EM）成像和下游计算分析。产生的3D结构揭示了野生型BRCA1与包含K63连接的泛素部分的RNA聚合酶II（RNAP II）核心复合物结合的方式，这是DNA修复的推定信号。重要的是，我们还确定了与野生型复合物相比，具有BRCA15382insC突变的分子装配体表现出改变的蛋白质相互作用和泛素化模式。总体而言，我们的分析证明对于开发新的涉及患者源性癌细胞的结构肿瘤学应用是最佳的，同时扩展了我们对BRCA1在基因调控事件中作用的认识。