title: Dynamics of chromosome compaction during mitosis.
abstract: We have quantitatively studied the space-time dynamics of mitotic chromosome compaction in cultured amphibian cells. After collecting digital phase-contrast images we have done digital image analysis to study spatial correlations in density. We find a characteristic distance at which the strongest correlations occur, which provides a quantitative measure of the size of patches of dense chromatin during interphase and early prophase. Later in mitosis, this length corresponds to the thickness of prophase and metaphase chromosomes. We find that during interphase strong correlations exist at a few-micrometer length; during prophase this correlation length progressively drops as the chromosomes are compacted. Our data are explained by a model based on assembly of chromatin loops onto already fiberlike interphase chromosomes. To test this model we have microinjected cobalt hexamine trichloride into interphase nuclei and have observed the rapid condensation of the interphase chromatin into thick fibers with a spacing similar to the native-state interphase correlation length determined from our image analysis.
authors.affiliation: Department of Physics, University of Illinois at Chicago, 60607-7059, USA. asarkar@callan.phy.uic.edu
authors.forename: Abhijit
authors.initials: A
authors.lastname: Sarkar
authors.forename: Sertac
authors.initials: S
authors.lastname: Eroglu
authors.forename: Michael G
authors.initials: MG
authors.lastname: Poirier
authors.forename: Prateek
authors.initials: P
authors.lastname: Gupta
authors.forename: Ajay
authors.initials: A
authors.lastname: Nemani
authors.forename: John F
authors.initials: JF
authors.lastname: Marko
mesh_terms: D000818:Animals; D002412:Cations; D002460:Cell Line; D002843:Chromatin / Q000502:physiology*; D002875:Chromosomes; D003593:Cytoplasm / Q000378:metabolism; D007399:Interphase; D008938:Mitosis / Q000502:physiology*; D012455:Salamandridae; D013997:Time Factors
chemical_list: D002412:Cations; D002843:Chromatin