Stable chromosomal units determine the spatial and temporal organization of DNA replication

作者：Nicolas Sadoni, M. Cristina Cardoso, Ernst H. K. Stelzer, Heinrich Leonhardt, Daniele Zink · 发表于：Journal of Cell Science · 年份：2004 · DOI：10.1242/jcs.01412 · 被引用次数：106 · 研究领域：DNA Repair Mechanisms、Microtubule and mitosis dynamics、Genomics and Chromatin Dynamics

DNA replication occurs in mammalian cells at so-called replication foci occupying defined nuclear sites at specific times during S phase. It is an unresolved problem how this specific spatiotemporal organization of replication foci is determined. Another unresolved question remains as to what extent DNA is redistributed during S phase. To investigate these problems, we visualized the replicating DNA and the replication machinery simultaneously in living HeLa cells. Time-lapse analyses revealed that DNA was not redistributed to other nuclear sites during S phase. Furthermore, the results showed that DNA is organized into stable aggregates equivalent to replication foci. These aggregates, which we call sub-chromosomal foci, stably maintained their replication timing from S phase to S phase. During S-phase progression, the replication machinery sequentially proceeded through spatially adjacent sets of sub-chromosomal foci. These findings imply that the specific nuclear substructure of chromosomes and the order of their stable subunits determine the spatiotemporal organization of DNA replication.