title: Uniform Contraction-Expansion Description of Relative Centromere and Telomere Motion.
abstract: Internal organization and dynamics of the eukaryotic nucleus have been at the front of biophysical research in recent years. It is believed that both dynamics and location of chromatin segments are crucial for genetic regulation. Here we study the relative motion between centromeres and telomeres at various distances and at times relevant for genetic activity. Using live-imaging fluorescent microscopy coupled to stochastic analysis of relative trajectories, we find that the interlocus motion is distance-dependent with a varying fractional memory. In addition to short-range constraining, we also observe long-range anisotropic-enhanced parallel diffusion, which contradicts the expectation for classic viscoelastic systems. This motion is linked to uniform expansion and contraction of chromatin in the nucleus, and leads us to define and measure a new (to our knowledge) uniform contraction-expansion diffusion coefficient that enriches the contemporary picture of nuclear behavior. Finally, differences between loci types suggest that different sites along the genome experience distinctive coupling to the nucleoplasm environment at all scales.
authors.affiliation: Physics Department & Institute of Nanotechnology, Bar Ilan University, Ramat Gan, Israel. Electronic address: eldad.kepten@biu.ac.il.
authors.forename: Eldad
authors.initials: E
authors.lastname: Kepten
authors.affiliation: Hugo Steinhaus Center, Department of Mathematics, Wroclaw University of Technology, Wroclaw, Poland.
authors.forename: Aleksander
authors.initials: A
authors.lastname: Weron
authors.affiliation: Physics Department & Institute of Nanotechnology, Bar Ilan University, Ramat Gan, Israel.
authors.forename: Irena
authors.initials: I
authors.lastname: Bronstein
authors.affiliation: Hugo Steinhaus Center, Department of Mathematics, Wroclaw University of Technology, Wroclaw, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Burnecki
authors.affiliation: Physics Department & Institute of Nanotechnology, Bar Ilan University, Ramat Gan, Israel. Electronic address: yuval.garini@biu.ac.il.
authors.forename: Yuval
authors.initials: Y
authors.lastname: Garini
mesh_terms: D016880:Anisotropy; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D053145:Cell Nucleus Size / Q000502:physiology; D002503:Centromere / Q000378:metabolism*; D003198:Computer Simulation; D004058:Diffusion; D006801:Humans; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D009038:Motion; D013269:Stochastic Processes; D016615:Telomere / Q000378:metabolism*; D013995:Time; D014741:Video Recording; D055682:Viscoelastic Substances / Q000378:metabolism
chemical_list: D055682:Viscoelastic Substances