Superresolution imaging reveals spatiotemporal propagation of human replication foci mediated by CTCF-organized chromatin structures.
Proc Natl Acad Sci U S A
; 117(26): 15036-15046, 2020 06 30.
Article
in En
| MEDLINE
| ID: mdl-32541019
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.
Key words
Full text:
1
Database:
MEDLINE
Main subject:
Chromatin
/
DNA Replication
/
CCCTC-Binding Factor
Type of study:
Prognostic_studies
Limits:
Humans
Language:
En
Year:
2020
Type:
Article