Eukaryotic genome replication depends on thousands of DNA replication origins (ORIs). A major challenge is to learn ORI biology in multicellular organisms in the context of growing organs to understand their developmental plasticity. We have identified a set of ORIs of Arabidopsis thaliana and their chromatin landscape at two stages of post-embryonic development. ORIs associate with multiple chromatin signatures including transcription start sites (TSS) but also proximal and distal regulatory regions and heterochromatin, where ORIs colocalize with retrotransposons. In addition, quantitative analysis of ORI activity led us to conclude that strong ORIs have high GC content and clusters of GGN trinucleotides. Development primarily influences ORI firing strength rather than ORI location. ORIs that preferentially fire at early developmental stages colocalize with GC-rich heterochromatin, but at later stages with transcribed genes, perhaps as a consequence of changes in chromatin features associated with developmental processes. Our study provides the set of ORIs active in an organism at the post-embryo stage that should allow us to study ORI biology in response to development, environment, and mutations with a quantitative approach. In a wider scope, the computational strategies developed here can be transferred to other eukaryotic systems.

中文翻译：

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发射效率，染色质和转录的差异是拟南芥DNA复制起点发育可塑性的基础。

真核基因组复制取决于成千上万的DNA复制起点（ORIs）。一个主要的挑战是在器官生长的背景下学习多细胞生物中的ORI生物学，以了解它们的发育可塑性。我们已经确定了拟南芥在胚胎发育后两个阶段的一组ORIs及其染色质分布。ORIs与多个染色质特征相关联，包括转录起始位点（TSS），还包括近端和远端调节区以及异染色质，其中ORIs与逆转录转座子共定位。此外，对ORI活性的定量分析使我们得出结论，即强ORI具有高GC含量和GGN三核苷酸簇。发展主要影响ORI的发射强度，而不是ORI的位置。优先在早期发育阶段激发的ORIs与富含GC的异染色质共定位，但在后期与转录的基因共定位，这可能是与发育过程相关的染色质特征变化的结果。我们的研究提供了在胚后阶段在生物体中活跃的ORIs集合，这应该使我们能够通过定量方法研究ORI生物学对发育，环境和突变的反应。在更广泛的范围内，此处开发的计算策略可以转移到其他真核系统。我们的研究提供了在胚后阶段在有机体中活跃的ORIs集合，这应该使我们能够通过定量方法研究ORI生物学对发育，环境和突变的反应。在更广泛的范围内，此处开发的计算策略可以转移到其他真核系统。我们的研究提供了在胚后阶段在有机体中活跃的ORIs集合，这应该使我们能够通过定量方法研究ORI生物学对发育，环境和突变的反应。在更广泛的范围内，此处开发的计算策略可以转移到其他真核系统。