Abstract
Tracking of fluorescently labeled chromosomal loci in live bacterial cells reveals a robust scaling of the mean square displacement (MSD) as . We propose that the observed motion arises from relaxation of the Rouse modes of the DNA polymer within the viscoelastic environment of the cytoplasm. The time-averaged and ensemble-averaged MSD of chromosomal loci exhibit ergodicity, and the velocity autocorrelation function is negative at short time lags. These observations are most consistent with fractional Langevin motion and rule out a continuous time random walk model as an explanation for anomalous motion in vivo.
- Received 6 December 2009
DOI:https://doi.org/10.1103/PhysRevLett.104.238102
©2010 American Physical Society
Synopsis
Scenes from a cytoplasm
Published 18 June 2010
Time-lapse images of DNA molecules in a bacterial cell reveal the forces that can inhibit diffusion.
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