title: Stochasticity in gene expression in a cell-sized compartment.
abstract: The gene expression in a clonal cell population fluctuates significantly, and its relevance to various cellular functions is under intensive debate. A fundamental question is whether the fluctuation is a consequence of the complexity and redundancy in living cells or an inevitable attribute of the minute microreactor nature of cells. To answer this question, we constructed an artificial cell, which consists of only necessary components for the gene expression (in vitro transcription and translation system) and its boundary as a microreactor (cell-sized lipid vesicle), and investigated the gene expression noise. The variation in the expression of two fluorescent proteins was decomposed into the components that were correlated and uncorrelated between the two proteins using a method similar to the one used by Elowitz and co-workers to analyze the expression noise in E. coli. The observed fluctuation was compared with a theoretical model that expresses the amplitude of noise as a function of the average number of intermediate molecules and products. With the assumption that the transcripts are partly active, the theoretical model was able to well describe the noise in the artificial system. Furthermore, the same measurement for E. coli cells harboring an identical plasmid revealed that the E. coli exhibited a similar level of expression noise. Our results demonstrated that the level of fluctuation found in bacterial cells is mostly an intrinsic property that arises even in a primitive form of the cell.
authors.affiliation: †Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Yamadaoka 1-5, Suita, Osaka 565-0871, Japan.|‡Quantitative Biology Center (QBiC), Riken, Fuedai 6-2-3, Suita, Osaka 565-0874, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Nishimura
authors.affiliation: †Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Yamadaoka 1-5, Suita, Osaka 565-0871, Japan.
authors.forename: Saburo
authors.initials: S
authors.lastname: Tsuru
authors.affiliation: §Faculty of Science and Engineering, Chuo University, Kasuga 1-13-27, Bunkyo-ku, Tokyo 112-8551, Japan.|∥Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency, Yamadaoka 1-5, Suita, Osaka 565-0871, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: †Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Yamadaoka 1-5, Suita, Osaka 565-0871, Japan.|∥Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency, Yamadaoka 1-5, Suita, Osaka 565-0871, Japan.|⊥Department of Frontier Biosciences, Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 1-5, Suita, Osaka 565-0871, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yomo
mesh_terms: D058045:Artificial Cells / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression / Q000235:genetics*; D008954:Models, Biological; D010957:Plasmids / Q000235:genetics; D014176:Protein Biosynthesis / Q000235:genetics; D013269:Stochastic Processes; D014158:Transcription, Genetic / Q000235:genetics
keywords: artificial cell; fluctuation; gene expression