Data from: A phase oscillator model of cell cycles reveals nuclear density control in a branched fungal network

Microscopy data from the paper: Data from: A phase oscillator model of cell cycles reveals nuclear density control in a branched fungal network.

Paper abstract: Maintaining an appropriate nuclear-to-cytoplasmic ratio is essential across cell types for physiological function, and mechanisms of size control have been extensively studied in mononucleate cells. Much less is known about how comparable control is achieved in cells where many nuclei share a common cytoplasm, which are seen in many contexts including muscle, placenta and filamentous fungi. The filamentous fungus Ashbya gossypii forms a branching mycelial network in which individual nuclei divide asynchronously, while the number of nuclei per cell volume (the nuclear density) is tightly controlled. How global regulation of nuclear density coexists with local cell cycle asynchrony remains unclear. To address this we model nuclei as a dividing population of phase oscillators within a branching cell network and parameterize the model with measurements from Ashbya cells. The model demonstrates that asynchrony is required to prevent large density fluctuations that would result from synchronous division, and that introducing a nuclear-density checkpoint to the cell cycles leads to synchrony if it is the only mechanism of density control. We find that coupling branch formation to nuclear density both stabilizes nuclear density and prevents the emergence of synchronous cycles. Supporting these predictions, we demonstrate that mutants with branching defects and increased cell cycle synchrony display greater variability in nuclear density. Our results indicate that asynchronous nuclear cycles together with density-responsive branching maintain a constant nuclear density, revealing a strategy for regulating the nuclear-to-cytoplasmic ratio in large multinucleate cells.

本显微数据集来自以下论文：《细胞周期相位振荡器模型揭示分支真菌网络中的核密度调控机制》。

论文摘要：维持适宜的核质比（nuclear-to-cytoplasmic ratio）对所有细胞类型的生理功能均至关重要，而细胞体积调控机制在单核细胞（mononucleate cells）中已得到广泛研究。但对于多细胞核共享同一细胞质的细胞（该类细胞广泛存在于肌肉、胎盘及丝状真菌等多种生理场景中），如何实现类似的体积调控，目前仍知之甚少。丝状真菌棉阿舒囊霉（Ashbya gossypii）可形成分支菌丝网络，其中单个细胞核异步分裂，而单位细胞体积内的细胞核数量（即核密度（nuclear density））受到严格调控。核密度的全局调控如何与局部细胞周期异步性共存，目前仍不明确。为解决这一问题，本研究将细胞核建模为分支细胞网络内的分裂型相位振荡器（phase oscillator）种群，并基于棉阿舒囊霉细胞的测量数据对模型进行参数化（parameterize）。模型结果表明，异步性可有效避免同步分裂引发的剧烈核密度波动；且若仅以核密度检查点（nuclear-density checkpoint）作为密度调控的唯一机制，细胞周期引入该检查点后会导致细胞核分裂同步化。本研究发现，将分支形成与核密度进行耦合，既可稳定核密度，又能抑制同步化细胞周期的出现。为验证上述预测，本研究发现存在分支缺陷且细胞周期同步性升高的突变株，其核密度变异程度更高。本研究结果表明，异步细胞核周期与响应核密度的分支过程共同维持了恒定的核密度，揭示了大型多核细胞（multinucleate cells）中核质比的调控策略。