MECHANISMS OF GENOME MAINTENANCE BY BROMODOMAIN CHROMATIN READER PROTEINS

项目总结 基于染色质的DNA损伤反应(DDR)机制是预防基因组和 表观基因组不稳定，这是癌症的特征。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。该提案旨在通过以下方式解决这一问题 综合分析所有42个人溴域(BRD)蛋白在DDR中的参与情况。这个 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，参与了 检测、发送信号和修复DNA损伤。因此，BRD蛋白是很有吸引力的候选蛋白 阅读受损的染色质以调节基因组-表观基因组的完整性。我们对BRD蛋白的完整分析 DNA损伤部位的动态变化提供了一个前所未有的视角，说明BRD蛋白参与了 DDR。从我们的研究中，我们确定了三分之一的BRD蛋白在DNA损伤时重新定位，这是一种现象 常见的DNA损伤因素。这些发现表明，BRD蛋白广泛参与了 并为进一步确定BRD蛋白在DDR中的功能提供了一个实验框架。 我们在一种新的转录依赖的DNA损伤识别中鉴定了BRD蛋白ZMYND8 路径。ZMYND8通过招募NuRD识别和抑制受损染色质的主动转录 染色质-重塑复合体到这些部位，通过同源重组促进修复。其他内容 基于我们结果的研究有望为染色质受损程度提供关键的机械学见解。 被识别和处理以促进DNA修复。然后我们将在鉴定其他DNA的基础上 损伤募集了BRD蛋白，包括TRIM24-TRIM28-TRIM33，以识别其他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将 为他们的DDR功能提供洞察力，但也将为他们参与癌症提供重要信息。 我们还将检验我们的假设，即非DNA损伤招募的BRD蛋白参与了DDR。这些 研究将提供对BRD染色质阅读器蛋白如何协调的前所未有的理解 以染色质为基础的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ZMYND8和NuRD经常在癌症和组蛋白中发生突变 在几种癌症中，ZMYND8结合的乙酰化作用被解除了调控。BRD蛋白和DDR因子都是 被作为治疗靶点积极追逐。靶向小分子抑制剂的临床前研究进展 BRD(例如，BRD4抑制剂JQ1和Beti)使通过靶向BRD蛋白来给表观基因组下药成为一种 药物发现的主要方向。我们对DDR中BRD蛋白的鉴定具有重要的意义 靶向癌症中的这些蛋白质。从这项提议中获得的信息将有助于指导治疗策略 靶向BRD蛋白作为DDR在癌症中的转录调节和介体。

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.