Superresolution imaging reveals spatiotemporal propagation of human replication foci mediated by CTCF-organized chromatin structures
Su, QP Zhao, ZW Meng, L Ding, M Zhang, W Li, Y Liu, M Li, R Gao, YQ Xie, XS
Su, QP
Meng, L
Ding, M
Zhang, W
Li, Y
Liu, M
Li, R
Gao, YQ
Xie, XS
Citations
Altmetric:
Alternative Title
Abstract
Mammalian DNA replication is initiated at numerous replication origins, which are clustered into thousands of replication domains (RDs) across the genome. However, it remains unclear whether the replication origins within each RD are activated stochastically or preferentially near certain chromatin features. To understand how DNA replication in single human cells is regulated at the sub-RD level, we directly visualized and quantitatively characterized the spatiotemporal organization, morphology, and in situ epigenetic signatures of individual replication foci (RFi) across S-phase at superresolution using stochastic optical reconstruction microscopy. Importantly, we revealed a hierarchical radial pattern of RFi propagation dynamics that reverses directionality from early to late S-phase and is diminished upon caffeine treatment or CTCF knockdown. Together with simulation and bioinformatic analyses, our findings point to a "CTCF-organized REplication Propagation" (CoREP) model, which suggests a nonrandom selection mechanism for replication activation at the sub-RD level during early S-phase, mediated by CTCF-organized chromatin structures. Collectively, these findings offer critical insights into the key involvement of local epigenetic environment in coordinating DNA replication across the genome and have broad implications for our conceptualization of the role of multiscale chromatin architecture in regulating diverse cell nuclear dynamics in space and time.
Keywords
DNA replication, chromatin organization, epigenetic environment, spatiotemporal dynamics, superresolution microscopy
Source Title
Proceedings of the National Academy of Sciences of the United States of America
Publisher
Proceedings of the National Academy of Sciences
Series/Report No.
Collections
Rights
Date
2020-06-30
DOI
10.1073/pnas.2001521117
Type
Article