Short-time movement of E. coli chromosomalloci depends on coordinate andsubcellular localization

摘要

In bacteria, chromosomal architecture shows strong spatial and temporal organization, andregulates key cellular functions, such as transcription. Tracking the motion of chromosomalloci at short timescales provides information related to both the physical state of thenucleo–protein complex and its local environment, independent of large-scale motions relatedto genome segregation. Here we investigate the short-time (0.1–10 s) dynamics offluorescently labelled chromosomal loci in Escherichia coli at different growth rates. At thesetimescales, we observe for the first time a dependence of the loci’s apparent diffusion on boththeir subcellular localization and chromosomal coordinate, and we provide evidence that theproperties of the chromosome are similar in the tested growth conditions. Our resultsindicate that either non-equilibrium fluctuations due to enzyme activity or the organization ofthe genome as a polymer–protein complex vary as a function of the distance from the originof replication.