Speaker
Description
Periodic oscillations in Cyclin B–Cdk1 activity function as the core timing mechanism that controls the onset of cell division. These oscillations emerge from a complex regulatory network of interacting proteins, creating a self-sustained biochemical oscillator that regulates mitotic progression. In spatially extended systems, such oscillatory behavior can propagate as waves that synchronize mitotic entry across space. This mechanism supports rapid and coordinated divisions in large embryos, such as those of Drosophila and Xenopus, which can reach millimeter-scale dimensions. Nevertheless, the mechanisms by which these waves coordinate mitosis across both space and time remain incompletely understood.
Here, we present experimental results using Xenopus laevis egg extracts to reconstitute mitotic waves in vitro. We observe a transition from phase waves to trigger waves, which is explained through mathematical modeling that underscores the roles of transient dynamics and spatial heterogeneity. To further probe how these collective dynamics emerge, we introduce nuclei and apply boundary perturbations to examine how wave-mediated coupling promotes entrainment and spatial coordination of mitosis. Together, these findings clarify how phase and trigger waves contribute to the spatial organization of mitotic progression.
