2015/03/03 by Naama Brenner, Erez Braun, Brenner, Naama +9
Biochemistry, Genetics and Molecular Biology · #Biological Physics (physics.bio-ph) #Cell Behavior (q-bio.CB) #Evolution and Genetic Dynamics #FOS: Biological sciences #FOS: Physical sciences #Gene Regulatory Network Analysis #Single-cell and spatial transcriptomics
paper · pdf · doi:10.48550/arxiv.1503.01046
openalex publication_date 2015/03/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Protein variability in single cells has been studied extensively in\npopulations, but little is known about temporal protein fluctuations in a\nsingle cell over extended times. We present here traces of protein copy number\nmeasured in individual bacteria over multiple generations and investigate their\nstatistical properties, comparing them to previously measured population\nsnapshots. We find that temporal fluctuations in individual traces exhibit the\nsame universal features as those previously observed in populations. Scaled\nfluctuations around the mean of each trace exhibit the same universal\ndistribution shape as found in populations measured under a wide range of\nconditions and in two distinct microorganisms. Additionally, the mean and\nvariance of the traces over time obey the same quadratic relation. Analyzing\nthe temporal features of the protein traces in individual cells, reveals that\nwithin a cell cycle protein content increases as an exponential function with a\nrate that varies from cycle to cycle. This leads to a compact description of\nthe protein trace as a 3-variable stochastic process - the exponential rate,\nthe cell-cycle duration and the value at the cycle start - sampled once each\ncell cycle. This compact description is sufficient to preserve the universal\nstatistical properties of the protein fluctuations, namely, the protein\ndistribution shape and the quadratic relationship between variance and mean.\nOur results show that the protein distribution shape is insensitive to\nsub-cycle intracellular microscopic details and reflects global cellular\nproperties that fluctuate between generations.\n