Single-cell protein dynamics reproduce universal fluctuations in cell populations
Single-cell protein dynamics reproduce universal fluctuations in cell populations
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DOI：
10.1140/epje/i2015-15102-8
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发表时间：
2015-09-28
影响因子：
1.8
通讯作者：
Salman, Hanna
中科院分区：
文献类型：
--
作者：
Brenner, Naama;Braun, Erez;Salman, Hanna
单细胞中的蛋白质变异性已经在群体中得到了广泛的研究，但对单细胞中蛋白质在长时间内的时间波动知之甚少。我们在这里展示了在多代细菌中测量的蛋白质拷贝数的痕迹，并研究了它们的统计特性，将它们与以前测量的种群快照进行了比较。我们发现，在个别细胞的时间波动表现出相同的属性，如以前观察到的人口。每个迹线的平均值周围的尺度波动表现出在广泛的条件下和两种不同的微生物中测量的种群的普遍分布形状;迹线随时间的平均值和方差服从相同的二次关系。分析单个蛋白质痕迹表明，在细胞周期内，蛋白质含量呈指数级增加，其速率因周期而异。这导致了一个紧凑的描述的痕迹作为一个3变量的随机过程指数率，细胞周期持续时间和价值在周期开始-采样一次周期。这种描述足以再现蛋白质波动的两个普遍统计特性。我们的研究结果表明，蛋白质分布的形状是不敏感的亚周期细胞内的微观细节，并反映了全球细胞特性，世代之间的波动。
Protein variability in single cells has been studied extensively in populations, but little is known about temporal protein fluctuations in a single cell over extended times. We present here traces of protein copy number measured in individual bacteria over multiple generations and investigate their statistical properties, comparing them to previously measured population snapshots. We find that temporal fluctuations in individual cells exhibit the same properties as those previously observed in populations. Scaled fluctuations around the mean of each trace exhibit the universal distribution shape measured in populations under a wide range of conditions and in two distinct microorganisms; the mean and variance of the traces over time obey the same quadratic relation. Analyzing the individual protein traces reveals that within a cell cycle protein content increases exponentially, with a rate that varies from cycle to cycle. This leads to a compact description of the trace as a 3-variable stochastic process exponential rate, cell cycle duration and value at the cycle start- sampled once a cycle. This description is sufficient to reproduce both universal statistical properties of the protein fluctuations. Our results show that the protein distribution shape is insensitive to sub-cycle intracellular microscopic details and reflects global cellular properties that fluctuate between generations.