DNA 复制起始受RNA聚合酶II介导的三维染色质结构调控的机制研究

为确保亲代遗传信息准确地传递给子代，需要对DNA复制过程进行严格的控制。DNA复制异常可导致染色体结构变异、DNA双链断裂甚至癌症发生。转录及其调控与DNA复制起始紧密相关，但尚不明确其具体调控机制。近期三维基因组结构对转录调控作用的研究进展为探讨DNA复制起始机制提供了新的思路。课题组前期发现DNA复制起始区富集于RNA聚合酶II介导的三维染色质结构（RNAPII结构），细胞类型特异性DNA复制起始区对应着特异性RNAPII结构。本项目拟进一步研究DNA复制起始区的建立与RNAPII结构间的关系，鉴定利于复制起始的RNAPII结构组成特征，解析细胞特异性复制起始区与特异性RNAPII结构之间的关系，利用CRISPR-Cas9验证RNAPII结构在复制起始过程中的作用。研究结果可望阐明RNAPII结构调控DNA复制起始的分子机制，拓展对转录、三维染色质结构和DNA复制间协调机制的认识。

DNA replication requires stringent regulation to faithfully transmit genetic information to daughter cells and to maintain genome stability. Abnormal DNA replication may result in structural variations, double-strand DNA breaks, and even tumorigenesis. Transcription and its regulation contribute to establish DNA replication initiation, but the mechanism is poorly understood. Recent studies revealing the function of 3D genomic structures on transcription regulation provide a novel perspective for understanding the mechanism of DNA replication initiation. Our preliminary results show that the DNA replication initiation zones are enriched in RNA polymerase II (RNAPII) mediated 3D chromatin structures, and cell-type specific initiation zones are concordant with cell-type specific RNAPII mediated 3D chromatin structures. Here we propose to further dissect the relationship between the initiation zone establishment and RNAPII-mediated chromatin structure, characterize initiation-zone-associated chromatin interactions and explore the linkage between cell-type-specific initiation zones and cell-type specific RNAPII-mediated 3D chromatin interactions. We will apply the CRISPR-Cas9 technique to verify the function of RNAPII-mediated 3D chromatin interactions in the regulation of DNA replication initiation. The outcomes of this study will reveal the role of RNAPII-mediated 3D chromatin structures in regulating DNA replication initiation, and improve the understanding of the coordination mechanism between transcription activities, RNAPII-mediated 3D chromatin structures, and DNA replication initiation.