BRCA1 and the regulation of chromatin dynamics in gene expression

项目摘要 BRCA1是一种公认的肿瘤抑制因子，在散发性和多发性卵巢癌的发生发展中发挥关键作用。 遗传性乳腺癌和卵巢癌。被认为是基因组完整性的“主调节者”，BRCA1一直是 几乎与染色质生物学的方方面面有关。BRCA1的缺失是胚胎致命的，并导致细胞 应激信号、DNA修复、细胞周期进程、细胞凋亡、染色质凝聚和基因缺陷 表情。这些过程中的每一个都涉及到调节空间的染色质结构的动态变化 以及对基因组DNA的临时访问。尽管与染色质修饰的各种机制有关 和重塑，对BRCA1的S在调节染色质动力学中的作用的机制的理解已经被 由于其功能失调的全球后果，很难确定。最近，我们建立了一个无细胞的 支持非洲爪哇卵提取液中自然显色的质粒底物转录的系统。 提取物中的转录活性与染色质修饰和结构的变化密切相关， 为研究染色质动力学调节如何控制基因表达提供了一个强有力的工具。通过耦合 这个系统已经建立了用来阐明DNA复制和DNA修复机制的方法，我们 现在准备研究这些基本过程之间的相互作用。事实上，BRCA1的S扮演的是 基因组压力传感器将其置于基因组利用、维护和修复的中心。在这 提案中，我们试图了解BRCA1和其他染色质调节因子是如何控制DNA在 对不同细胞事件的反应。总而言之，这些研究将提供新的机制洞察 染色质信号的复杂性仍然是基因组的一个基本的，但知之甚少的调节因子 正直。

Project Summary BRCA1 is an established tumor suppressor that plays a critical role in the development of both sporadic and hereditary breast and ovarian cancer. Considered a “master regulator” of genome integrity, BRCA1 has been linked to nearly all aspects of chromatin biology. Loss of BRCA1 is embryonic lethal and leads to cellular defects in stress signaling, DNA repair, cell cycle progression, apoptosis, chromatin condensation, and gene expression. Each of these processes involves dynamic changes in chromatin architecture that regulate spatial and temporal access to genomic DNA. Although implicated in various mechanisms of chromatin modification and remodeling, a mechanistic understanding of BRCA1’s role in regulating chromatin dynamics has been difficult to establish due to the global consequences of its dysfunction. Recently, we established a cell-free system that supports transcription of naturally chromatinized plasmid substrates in Xenopus egg extract. Transcriptional activity in extract is tightly coupled to changes in chromatin modification and structure, providing a powerful tool to study how regulation of chromatin dynamics controls gene expression. By coupling this system with established approaches used to elucidate mechanisms of DNA replication and DNA repair, we are now poised to examine the interplay between these fundamental processes. Indeed, BRCA1’s role as a sensor for genomic stress places it at the center of genome utilization, maintenance, and repair. In this proposal, we seek to understand how BRCA1 and other chromatin regulators control access to DNA in response to different cellular events. Together, these studies will provide new mechanistic insight into the complexities of chromatin signaling that remain an essential, but poorly understood regulator of genome integrity.