title: Chromatin position in human HepG2 cells: although being non-random, significantly changed in daughter cells.
abstract: Mammalian chromosomes occupy chromosome territories within nuclear space the positions of which are generally accepted as non-random. However, it is still controversial whether position of chromosome territories/chromatin is maintained in daughter cells. We addressed this issue and investigated maintenance of various chromatin regions of unknown composition as well as nucleolus-associated chromatin, a significant part of which is composed of nucleolus organizer region-bearing chromosomes. The photoconvertible histone H4-Dendra2 was used to label such regions in transfected HepG2 cells, and its position was followed up to next interphase. The distribution of labeled chromatin in daughter cells exhibited a non-random character. However, its distribution in a vast majority of daughter cells extensively differed from the original ones and the labeled nucleolus-associated chromatin differently located into the vicinity of different nucleoli. Therefore, our results were not consistent with a concept of preservation chromatin position. This conclusion was supported by the finding that the numbers of nucleoli significantly differed between the two daughter cells. Our results support a view that while the transfected daughter HepG2 cells maintain some features of the parental cell chromosome organization, there is also a significant stochastic component associated with reassortment of chromosome territories/chromatin that results in their positional rearrangements.
authors.affiliation: Institute of Cellular Biology and Pathology, Charles University in Prague, Czech Republic.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Cvacková
authors.forename: Martin
authors.initials: M
authors.lastname: Masata
authors.forename: David
authors.initials: D
authors.lastname: Stanĕk
authors.forename: Helena
authors.initials: H
authors.lastname: Fidlerová
authors.forename: Ivan
authors.initials: I
authors.lastname: Raska
mesh_terms: D002460:Cell Line; D002466:Cell Nucleolus / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000737:chemistry* / Q000378:metabolism; D002875:Chromosomes / Q000648:ultrastructure; D005347:Fibroblasts / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008856:Microscopy, Fluorescence / Q000379:methods; D013997:Time Factors
chemical_list: D002843:Chromatin; D006657:Histones