Data from: Loss of growth homeostasis by genetic decoupling of cell division from biomass growth: implication for size control mechanisms

Growing cells adjust their division time with biomass accumulation to maintain growth homeostasis. Size control mechanisms, such as the size checkpoint, provide an inherent coupling of growth and division by gating certain cell cycle transitions based on cell size. We describe genetic manipulations that decouple cell division from cell size, leading to the loss of growth homeostasis, with cells becoming progressively smaller or progressively larger until arresting. This was achieved by modulating glucose influx independently of external glucose. Division rate followed glucose influx, while volume growth was largely defined by external glucose. Therefore, the coordination of size and division observed in wild‐type cells reflects tuning of two parallel processes, which is only refined by an inherent feedback‐dependent coupling. We present a class of size control models explaining the observed breakdowns of growth homeostasis.

生长中的细胞会随生物质积累调整分裂时长，以维持生长稳态（growth homeostasis）。诸如细胞大小检查点（size checkpoint）这类大小调控机制，可基于细胞大小对特定细胞周期转变实施门控调控，从而实现生长与分裂的内在偶联。我们通过遗传操作实现了细胞分裂与细胞大小的解偶联，进而导致生长稳态丧失，细胞会持续逐渐变小或变大，直至发生增殖停滞。该实验通过独立于外界葡萄糖浓度的方式调控葡萄糖内流得以完成。分裂速率随葡萄糖内流水平发生变化，而细胞体积生长则主要由外界葡萄糖浓度决定。因此，在野生型细胞（wild-type cells）中观测到的大小与分裂的协调关系，实则反映了对两条平行过程的调校，而该协调机制仅通过依赖反馈的内在偶联得以优化完善。我们提出了一类大小调控模型，可解释所观测到的生长稳态失衡现象。