BRCA1 and the regulation of chromatin dynamics in gene expression

项目摘要 BRCA1是一种已确立的肿瘤抑制因子，在散发性和非散发性乳腺癌的发生中起关键作用。 遗传性乳腺癌和卵巢癌BRCA1被认为是基因组完整性的“主调节因子”， 与染色质生物学的几乎所有方面都有联系。BRCA1的缺失是胚胎致死的，并导致细胞凋亡。 应激信号传导、DNA修复、细胞周期进程、凋亡、染色质浓缩和基因缺陷 表情这些过程中的每一个都涉及到染色质结构的动态变化， 和暂时获取基因组DNA尽管与染色质修饰的各种机制有关， 和重塑，对BRCA1在调节染色质动力学中的作用的机制理解已经被 由于其功能失调的全球后果，难以建立。最近，我们建立了一个无细胞的 支持非洲爪蟾卵提取物中天然染色质化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紧密相关， 为研究染色质动力学调控如何控制基因表达提供了强有力的工具。通过耦合 该系统与用于阐明DNA复制和DNA修复机制的已建立方法一起， 现在正准备研究这些基本过程之间的相互作用。事实上，BRCA1作为一种 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 我们试图了解BRCA1和其他染色质调节因子如何控制DNA的进入， 对不同细胞事件的反应。总之，这些研究将提供新的机械洞察力， 染色质信号的复杂性仍然是一个重要的，但知之甚少的基因组调控 完整

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.