MECHANISMS OF GENOME MAINTENANCE BY BROMODOMAIN CHROMATIN READER PROTEINS

项目摘要 基于染色质的DNA损伤反应（DDR）机制是防止基因组和 表观基因组的不稳定性，这是癌症的标志。染色质如何促进基因组-表观基因组的完整性 对DNA损伤的反应是一个关键问题。这项建议旨在解决这个问题， 全面分析DDR中所有42种人布罗莫结构域（BRD）蛋白的参与。的 BRD是乙酰化的主要阅读器结构域。染色质乙酰化是一个关键的信号事件， 检测、发送信号和修复DNA损伤。因此，BRD蛋白代表了具有吸引力的候选物， 阅读受损染色质以介导基因组-表观基因组完整性。我们对BRD蛋白的完整分析 DNA损伤位点的动态提供了BRD蛋白参与DNA损伤的前所未有的观点。 DDR。从我们的研究中，我们确定了三分之一的BRD蛋白在DNA损伤后重新定位，这是一种现象， 常见的DNA损伤因子。这些发现表明BRD蛋白广泛参与了 的DDR，并提供了一个实验框架，以进一步确定在DDR中的BRD蛋白的功能。 我们在一种新的转录依赖的DNA损伤识别中鉴定了BRD蛋白ZMYND 8 通路ZMYND 8通过募集NuRD识别并抑制受损染色质的主动转录 染色质重塑复合物的这些网站，以促进修复同源重组。额外 基于我们的研究结果的研究准备提供关键的机械见解如何受损的染色质是 识别和处理以促进DNA修复。然后我们将在其他DNA的鉴定基础上 损伤招募了包括TRIM 24-TRIM 28-TRIM 33在内的BRD蛋白，以确定额外的DDR途径 涉及BRD蛋白。几种BRD蛋白与癌症有关，这表明这些研究不仅 提供了对他们的DDR功能的见解，但也将提供他们参与癌症的重要信息。 我们还将测试我们的假设，即非DNA损伤招募的BRD蛋白参与DDR。这些 研究将提供前所未有的了解如何BRD染色质阅读器蛋白编排 基于染色质的DDR途径来保护基因组的完整性。 这项工作可能会影响癌症生物学，因为ZMYND 8和NuRD经常在癌症和组蛋白中发生突变。 ZMYND 8结合的乙酰化在几种癌症中失调。BRD蛋白和DDR因子都是 积极作为治疗目标。靶向小分子抑制剂的临床前成功 BRD（例如BRD 4抑制剂JQ 1和BETI）通过靶向BRD蛋白质使表观基因组药物化， 药物发现的主要方向。我们对DDR中BRD蛋白的鉴定对以下方面具有重要意义： 针对癌症中的这些蛋白质。从这一建议中获得的信息将有助于指导治疗策略 用于靶向BRD蛋白作为癌症中DDR的转录调节因子和介体。

PROJECT SUMMARY Chromatin-based DNA damage response (DDR) mechanisms are fundamental for preventing genome and epigenome instability, which are hallmarks of cancer. How chromatin promotes genome-epigenome integrity in response to DNA damage is a critical question. This proposal aims to address this question by comprehensively analyzing the involvement of all 42 human bromodomain (BRD) proteins in the DDR. The BRD is the primary reader domain of acetylation. Chromatin acetylation is a key signaling event involved in detecting, signaling and repairing DNA damage. Thus, BRD proteins represent attractive candidates for reading damaged chromatin to mediate genome-epigenome integrity. Our complete analysis of BRD protein dynamics at DNA damage sites provides an unprecedented view of the involvement of BRD proteins in the DDR. From our studies, we identified one-third of BRD proteins relocalized upon DNA damage, a phenomenon common to DNA damage factors. These findings demonstrate the widespread involvement of BRD proteins in the DDR and provide an experimental framework to further identify the function of BRD proteins in the DDR. We identified the BRD protein ZMYND8 in a novel transcription-dependent DNA damage recognition pathway. ZMYND8 recognizes and represses actively transcribing damaged chromatin by recruiting NuRD chromatin-remodeling complexes to these sites to facilitate repair by homologous recombination. Additional studies based on our results are poised to provide critical mechanistic insights into how damaged chromatin is recognized and processed to promote DNA repair. We will then build upon our identification of other DNA damage recruited BRD proteins, including TRIM24-TRIM28-TRIM33, to identify additional DDR pathways involving BRD proteins. Several BRD proteins are linked with cancer, suggesting these studies will not only provide insights into their DDR functions but will also provide vital information for their involvement in cancer. We will also test our hypothesis that non-DNA damage recruited BRD proteins are involved in the DDR. These studies will provide an unprecedented understanding of how BRD chromatin reader proteins orchestrate chromatin-based DDR pathways to protect the integrity of the genome. This work could impact cancer biology as ZMYND8 and NuRD are often mutated in cancer and histone acetylations bound by ZMYND8 are deregulated in several cancers. BRD proteins and DDR factors are both actively being pursued as therapeutic targets. The pre-clinical success of small molecule inhibitors targeting the BRD (e.g. BRD4 inhibitors JQ1 and BETI) has made drugging the epigenome by targeting BRD proteins a major direction for drug discovery. Our identification of BRD proteins in the DDR has important implications for targeting these proteins in cancer. Information gained from this proposal will help guide therapeutic strategies for targeting BRD proteins as transcriptional regulators and mediators of the DDR in cancer.