Ciardo Diletta, Haccard Olivier, de Carli Francesco, Hyrien Olivier, Goldar Arach, Marheineke Kathrin
Institut de Biologie de l'Ecole Normale Supérieure, Ecole Normale Supérieure, CNRS, INSERM, Université PSL, F-75005 Paris, France.
Université Paris-Saclay, CNRS, Institut des Neurosciences Paris-Saclay (NeuroPsi), F-91400 Saclay, France.
Nucleic Acids Res. 2025 Jan 24;53(3). doi: 10.1093/nar/gkaf007.
Large vertebrate genomes duplicate by activating tens of thousands of DNA replication origins, irregularly spaced along the genome. The spatial and temporal regulation of the replication process is not yet fully understood. To investigate the DNA replication dynamics, we developed a methodology called RepliCorr, which uses the spatial correlation between replication patterns observed on stretched single-molecule DNA obtained by either DNA combing or high-throughput optical mapping. The analysis revealed two independent spatiotemporal processes that regulate the replication dynamics in the Xenopus model system. These mechanisms are referred to as a fast and a slow replication mode, differing by their opposite replication fork speed and rate of origin firing. We found that Polo-like kinase 1 (Plk1) depletion abolished the spatial separation of these two replication modes. In contrast, neither replication checkpoint inhibition nor Rap1-interacting factor (Rif1) depletion affected the distribution of these replication patterns. These results suggest that Plk1 plays an essential role in the local coordination of the spatial replication program and the initiation-elongation coupling along the chromosomes in Xenopus, ensuring the timely completion of the S phase.
大型脊椎动物基因组通过激活数以万计的DNA复制起点进行复制，这些起点在基因组上分布不规则。复制过程的时空调控尚未完全明确。为了研究DNA复制动态，我们开发了一种名为RepliCorr的方法，该方法利用通过DNA梳理或高通量光学图谱获得的拉伸单分子DNA上观察到的复制模式之间的空间相关性。分析揭示了在非洲爪蟾模型系统中调控复制动态的两个独立时空过程。这些机制被称为快速和慢速复制模式，它们的复制叉速度和起点激发速率相反。我们发现，Polo样激酶1（Plk1）缺失消除了这两种复制模式的空间分离。相比之下，复制检查点抑制和Rap1相互作用因子（Rif1）缺失均未影响这些复制模式的分布。这些结果表明，Plk1在非洲爪蟾中沿染色体的空间复制程序的局部协调以及起始-延伸偶联中起着至关重要的作用，确保S期的及时完成。
