title: Inflating bacterial cells by increased protein synthesis.
abstract: Understanding how the homeostasis of cellular size and composition is accomplished by different organisms is an outstanding challenge in biology. For exponentially growing Escherichia coli cells, it is long known that the size of cells exhibits a strong positive relation with their growth rates in different nutrient conditions. Here, we characterized cell sizes in a set of orthogonal growth limitations. We report that cell size and mass exhibit positive or negative dependences with growth rate depending on the growth limitation applied. In particular, synthesizing large amounts of "useless" proteins led to an inversion of the canonical, positive relation, with slow growing cells enlarged 7- to 8-fold compared to cells growing at similar rates under nutrient limitation. Strikingly, this increase in cell size was accompanied by a 3- to 4-fold increase in cellular DNA content at slow growth, reaching up to an amount equivalent to ~8 chromosomes per cell. Despite drastic changes in cell mass and macromolecular composition, cellular dry mass density remained constant. Our findings reveal an important role of protein synthesis in cell division control.
authors.affiliation: Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland basan@imsb.biol.ethz.ch hwa@ucsd.edu.
authors.forename: Markus
authors.initials: M
authors.lastname: Basan
authors.affiliation: Department of Physics, University of California at San Diego, La Jolla, CA, USA State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.
authors.forename: Manlu
authors.initials: M
authors.lastname: Zhu
authors.affiliation: Department of Physics, University of California at San Diego, La Jolla, CA, USA State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.
authors.forename: Xiongfeng
authors.initials: X
authors.lastname: Dai
authors.affiliation: Department of Physics, University of California at San Diego, La Jolla, CA, USA.
authors.forename: Mya
authors.initials: M
authors.lastname: Warren
authors.affiliation: Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sévin
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Wang
authors.affiliation: Department of Physics, University of California at San Diego, La Jolla, CA, USA Institute for Theoretical Studies, ETH Zürich, Zürich, Switzerland basan@imsb.biol.ethz.ch hwa@ucsd.edu.
authors.forename: Terence
authors.initials: T
authors.lastname: Hwa
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins
keywords: cell division; cell size; cell volume; cellular DNA; growth rate