Linking DNA replication to chromatin organization

遗传密码的准确复制及其忠实地分布到两个子细胞对于维持基因组稳定性和细胞存活至关重要。DNA被包装成紧凑的结构，由一组称为组蛋白的蛋白质促进，以构建染色质。染色质致密化影响包括DNA复制和基因表达在内的基本过程。这个项目将研究DNA复制和染色质压缩的过程是如何在细胞周期中协调的。这些结果将为复制蛋白在染色体分离和细胞周期进程中的作用提供新的见解。该项目还将为研究生、本科生和高中生提供在细胞和分子生物学以及基因组学领域进行研究的机会，包括高分辨率显微镜和延时成像等技术，以及对大规模基因组学数据的计算分析。保护基因组的完整性需要包装在染色质中的DNA的有效和可调控的复制，关于这个过程的重要的机械问题仍然没有解决。在后生动物中，复制前复合体（pre-replication Complex，preRC）因子、起源识别复合体（Origin Recognition Complex，ORC，由6个亚基组成）和ORC相关蛋白（ORCA/LRWD 1）在维持基因组稳定性和调节细胞周期进程的多个方面发挥关键作用。该项目的总体目标是通过使用ORCA/ORC作为探测这些过程的协调的工具来理解DNA复制和染色质组织的基本分子机制。具体目标是确定1）染色质如何调节起源许可和发射，2）preRC蛋白如何调节组成性和兼性异染色质的染色质组织。该项目利用多学科方法，包括细胞和分子生物学、生物化学和生物物理工具来解决这些基本问题。该研究结果有望揭示DNA复制与异染色质组织和染色体分离的整合线索，并阐明preRC蛋白在连接这些过程中的作用。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Accurate duplication of the genetic code and its faithful distribution to two daughter cells is critical for the maintenance of genome stability and cell survival. DNA is packaged into compact structures, facilitated by a group of proteins called histones, to build chromatin. Chromatin compaction impacts fundamental processes including DNA replication and gene expression. This project will investigate how the process of DNA replication and chromatin compaction are coordinated during the cell cycle. The outcomes will provide new insights into the role of replication proteins in chromosome segregation and cell cycle progression. The project will also provide opportunities for graduate, undergraduate and high school students to perform research in the fields of cell and molecular biology and genomics, including techniques such as high-resolution microscopy and time-lapse imaging, and computational analyses of large-scale genomics data.Safeguarding the integrity of the genome requires efficient and regulated replication of DNA packaged in chromatin, and important mechanistic questions about this process remain unresolved. In metazoans, pre-replication Complex (preRC) factors, Origin Recognition Complex (ORC, composed of six subunits) and ORC-associated proteins (ORCA/LRWD1) play pivotal roles in maintaining genomic stability and regulate multiple aspects of cell cycle progression. The overall goals of this project are to understand the fundamental molecular mechanisms of DNA replication and chromatin organization by using ORCA/ORC as a tool to probe the coordination of these processes. The specific aims are to determine 1) how chromatin regulates origin licensing and firing and, 2) how preRC proteins regulate chromatin organization at constitutive and facultative heterochromatin. The project utilizes multidisciplinary approaches, including cell and molecular biology, biochemical and biophysical tools to address these fundamental questions. The results are expected to uncover cues that integrate DNA replication with heterochromatin organization and chromosome segregation and elucidate the role of preRC proteins in connecting these processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.