title: Efficient supercoiling of DNA by a single condensin complex as revealed by electron spectroscopic imaging.
abstract: Condensin, a five-subunit protein complex essential for mitotic chromosome condensation from yeast to humans, introduces positive supercoils into DNA in an ATP-dependent manner in vitro. We report here the direct visualization of this supercoiling reaction by electron spectroscopic imaging. In the presence of ATP, a single condensin complex is capable of introducing two or more compensatory supercoils into the protein-free region of a closed circular DNA. Within the condensin-bound region, approximately 190 bp of DNA is organized into a compact structure with two distinct domains, indicative of the formation of two oriented gyres. The current results suggest that the action of condensin is more dynamic and more efficient than that postulated before, providing fundamental insight into the energy-dependent mechanism of higher order chromatin folding.
authors.affiliation: Programme in Cell Biology, Research Institute, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada. david.bazett-jones@sickkids.ca
authors.forename: David P
authors.initials: DP
authors.lastname: Bazett-Jones
authors.forename: Keiji
authors.initials: K
authors.lastname: Kimura
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hirano
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004278:DNA, Superhelical / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D008957:Models, Genetic; D046912:Multiprotein Complexes; D009690:Nucleic Acid Conformation; D013057:Spectrum Analysis / Q000379:methods; D014981:Xenopus
chemical_list: D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; C108312:condensin complexes; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases