title: Probabilistic RNA partitioning generates transient increases in the normalized variance of RNA numbers in synchronized populations of Escherichia coli.
abstract: We explore the effects of probabilistic RNA partitioning during cell division on the normalized variance of RNA numbers across generations of bacterial populations. We first characterize these effects in model cell populations, where gene expression is modeled as a delayed stochastic process, as a function of the synchrony in cell division, the rate of division, and the RNA degradation rate. We further explore the additional variance that arises if the partitioning is biased. Next, in Escherichia coli cells expressing RNA tagged with MS2d-GFP, we measured the normalized variance of RNA numbers across several generations, with cell divisions synchronized by heat shock. We show that synchronized cell populations exhibit transient increases in normalized variance following cell divisions, as predicted by the model, which are not observed in unsynchronized populations. We conclude that errors in partitioning of RNA molecules generate diversity between the offspring of individual bacteria and thus constitute a form of reproductive bet-hedging.
authors: Computational Systems Biology Research Group, Tampere University of Technology, Tampere, Finland.
authors: Jason
authors: J
authors: Lloyd-Price
authors: Maria
authors: M
authors: Lehtivaara
authors: Meenakshisundaram
authors: M
authors: Kandhavelu
authors: Sharif
authors: S
authors: Chowdhury
authors: Anantha-Barathi
authors: AB
authors: Muthukrishnan
authors: Olli
authors: O
authors: Yli-Harja
authors: Andre S
authors: AS
authors: Ribeiro
mesh_terms: D002455:Cell Division / Q000235:genetics*; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics; D015870:Gene Expression; D049452:Green Fluorescent Proteins / Q000235:genetics; D008954:Models, Biological; D010641:Phenotype; D012329:RNA, Bacterial / Q000032:analysis / Q000235:genetics*
chemical_list: D029968:Escherichia coli Proteins; D012329:RNA, Bacterial; D049452:Green Fluorescent Proteins