Allocation of gene products to daughter cells is determined by the age of the mother in single Escherichia coli cells

Abstract

Gene expression and growth rate are highly stochastic in Escherichia coli . Some of the growth rate variations result from the deterministic and asymmetric partitioning of damage by the mother to its daughters. One daughter, denoted the old daughter, receives more damage, grows more slowly and ages. To determine if expressed gene products are also allocated asymmetrically, we compared the levels of expressed green fluorescence protein in growing daughters descending from the same mother. Our results show that old daughters were less fluorescent than new daughters. Moreover, old mothers, which were born as old daughters, produced daughters that were more asymmetric when compared to new mothers. Thus, variation in gene products in a clonal E. coli population also has a deterministic component. Because fluorescence levels and growth rates were positively correlated, the aging of old daughters appears to result from both the presence of both more damage and fewer expressed gene products.

Cell size distribution of lineage data: Analytic results and parameter inference

“…For instance, Saccharomyces cerevisiae divides asymmetrically into two daughters with different sizes. Escherichia coli may also undergo asymmetric division with old daughters receiving fewer gene products than new daughters Shi et al. (2020) .…”

“…In addition, in Amir (2014) , (i) the partitioning at cell division is assumed to be symmetric (the mean partition ratio p is assumed to be 0.5) and (ii) in one of the two models considered there, the doubling time distribution is assumed to be Gaussian. In naturally occurring systems, the partitioning at cell division is often asymmetric Shi et al. (2020) .…”

“…For instance, Saccharomyces cerevisiae divides asymmetrically into two daughters with different sizes. Escherichia coli may also undergo asymmetric division with old daughters receiving fewer gene products than new daughters Shi et al (2020). Here, we follow the methodology that we devised in Jia and Grima (2020) and extend previous models by considering asymmetric partitioning at cell division: the mother cell divides into two daughters with different sizes.…”

Frequency domain analysis of fluctuations of mRNA and protein copy numbers within a cell lineage: theory and experimental validation

“…For instance, Saccharomyces cerevisiae divides asymmetrically into two daughters with different sizes. Escherichia coli may also undergo asymmetric division with old daughters receiving fewer gene products than new daughters [31]. Here we extend previous models by considering asymmetric binomial partitioning at cell division: the probability for a molecule being allocated to one daughter is p ≤ 1/2 and the probability of being allocated to the other is q = 1 − p (Fig.…”

Microbial metabolic noise

“…For example, nucleosome positioning has been shown to have noticeable effects on promoter accessibility, thus, resulting in a significant cell‐to‐cell protein variability in Saccharomyces cerevisiae (Small, Xi, Wang, Widom, & Licht, 2014). Epigenetic memory represents another related determinant, which was previously shown to bestow some cells with more copies of substrate transporters (Solopova et al, 2014), or to yield a deterministic asymmetry in the partitioning of gene‐products upon cell division (Shi et al, 2020). In the context of genetic determinants, mutations can emerge also spontaneously; however, they emerge at low rates, previously determined at 0.0022 mutations per hour for WT E. coli with less than 1% of those yielding an observable fitness effect (Robert et al, 2018).…”