title: Active dissociation of Hoechst 33342 from DNA in living mammalian cells.
abstract: The fluorescent dye Hoechst 33342, which binds tightly to DNA in the minor groove, can be effectively extracted from the DNA in vivo due to an energy-dependent process. It is the dissociation of the dye from DNA rather than its removal from a cell that has a critical role in this process. The dissociation can be suppressed by the topoisomerase-2 inhibitors novobiocin, ellipticine and etoposide. Breaks in the DNA also inhibit the process. The dissociation of the dye requires that DNA remain intact along a region of at least several thousand base pairs. It is proposed that DNA in mammalian cells is a dynamic, conformationally nonstable system and that topologically closed loops consisting of several thousand base pairs constantly appear and disappear in chromatin.
authors.affiliation: St. Petersburg Nuclear Physics Institute, Russia.
authors.forename: M V
authors.initials: MV
authors.lastname: Filatov
authors.forename: E Y
authors.initials: EY
authors.lastname: Varfolomeeva
mesh_terms: D001562:Benzimidazoles / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D004611:Ellipticines / Q000494:pharmacology; D005047:Etoposide / Q000494:pharmacology; D005453:Fluorescence; D006367:HeLa Cells; D006801:Humans; D009675:Novobiocin / Q000494:pharmacology; D059005:Topoisomerase II Inhibitors
chemical_list: D001562:Benzimidazoles; D004611:Ellipticines; D059005:Topoisomerase II Inhibitors; C034192:ellipticine; D009675:Novobiocin; D005047:Etoposide; D004247:DNA; C017807:bisbenzimide ethoxide trihydrochloride