The volumes and transcript counts of single cells reveal concentration homeostasis and capture biological noise.
Bottom Line: We compared three cell clones that differ only in the genomic integration site of an identical constitutively expressed reporter gene.We found that the cell-to-cell variability in the mRNA concentration is almost exclusively due to cell-to-cell variation in gene expression activity, whereas the cell-to-cell variation in mRNA number is larger, due to a significant contribution of cell volume variability.We concluded that the precise relationship between transcript number and cell volume sets the biological stochasticity of living cells.
Affiliation: Synthetic Systems Biology and Nuclear Organization Group, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.Show MeSH
Mentions: Next we combined the mRNA number and volume data of each cell to determine the statistics of cellular, cytoplasmic, and nuclear mRNA concentrations (Figure 3A). Figure 3B shows that the mean mRNA concentration differs among the three clones, indicating the dependence of expression levels on the gene location (Supplemental Information 2). Scaling of the mean and SD are independent. We observe higher mRNA concentrations in the cytoplasm than in the nucleus. Similar conclusions can be drawn from the mRNA numbers.
Affiliation: Synthetic Systems Biology and Nuclear Organization Group, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.