title: Short-time movement of E. coli chromosomal loci depends on coordinate and subcellular localization.
abstract: In bacteria, chromosomal architecture shows strong spatial and temporal organization, and regulates key cellular functions, such as transcription. Tracking the motion of chromosomal loci at short timescales provides information related to both the physical state of the nucleo-protein complex and its local environment, independent of large-scale motions related to genome segregation. Here we investigate the short-time (0.1-10 s) dynamics of fluorescently labelled chromosomal loci in Escherichia coli at different growth rates. At these timescales, we observe for the first time a dependence of the loci's apparent diffusion on both their subcellular localization and chromosomal coordinate, and we provide evidence that the properties of the chromosome are similar in the tested growth conditions. Our results indicate that either non-equilibrium fluctuations due to enzyme activity or the organization of the genome as a polymer-protein complex vary as a function of the distance from the origin of replication.
authors.affiliation: Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK.
authors.forename: Avelino
authors.initials: A
authors.lastname: Javer
authors.forename: Zhicheng
authors.initials: Z
authors.lastname: Long
authors.forename: Eileen
authors.initials: E
authors.lastname: Nugent
authors.forename: Marco
authors.initials: M
authors.lastname: Grisi
authors.forename: Kamin
authors.initials: K
authors.lastname: Siriwatwetchakul
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Dorfman
authors.forename: Pietro
authors.initials: P
authors.lastname: Cicuta
authors.forename: Marco
authors.initials: M
authors.lastname: Cosentino Lagomarsino
mesh_terms: D002876:Chromosomes, Bacterial / Q000378:metabolism*; D004058:Diffusion; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D056426:Genetic Loci / Q000235:genetics*; D009068:Movement; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors