title: Changes in chromosomal surface structure by different isolation conditions.
abstract: The human cell cycle was synchronized and the chromosomes were isolated by a centrifugation method using two representative solutions for chromosome isolation (a polyamine buffer, PAB and citric acid solution, CAS) and fixatives. The centrifugation method yielded sufficient amounts of human metaphase chromosomes. Observation of the isolated chromosomes by scanning electron microscopy (SEM) revealed two types of surface structure which have been repeatedly reported to date: the human chromosomes in the PAB were relatively smooth but covered irregularly with scaly structures, while the surface of the chromosomes in the CAS exhibited a dense fibrous structure with a uniform diameter of 50-70 nm. Comparison of proteins extracted from chromosomes isolated with the PAB and CAS clearly indicated the removal of linker histones, H1, from chromosomes isolated with the CAS. These findings imply that the two different images of human chromosomes frequently observed by SEM are due to the removal of peripheral chromosomal materials including linker histones and/or the depletion of linker histones which prevent the surface chromatin fibers from scattering.
authors.affiliation: Department of Biotechnology, Osaka University, Graduate School of Engineering, Suita, Osaka, Japan.
authors.forename: Takefumi
authors.initials: T
authors.lastname: Sone
authors.forename: Megumi
authors.initials: M
authors.lastname: Iwano
authors.forename: Shouhei
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ishihara
authors.forename: Naoto
authors.initials: N
authors.lastname: Hori
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takata
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Ushiki
authors.forename: Susumu
authors.initials: S
authors.lastname: Uchiyama
authors.forename: Kiichi
authors.initials: K
authors.lastname: Fukui
mesh_terms: D002453:Cell Cycle; D002458:Cell Fractionation / Q000379:methods; D002498:Centrifugation / Q000379:methods*; D002875:Chromosomes / Q000737:chemistry / Q000648:ultrastructure*; D005456:Fluorescent Dyes; D006657:Histones / Q000302:isolation & purification; D006801:Humans; D007211:Indoles; D020014:K562 Cells; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D008856:Microscopy, Fluorescence; D009687:Nuclear Proteins / Q000302:isolation & purification
chemical_list: D005456:Fluorescent Dyes; D006657:Histones; D007211:Indoles; D009687:Nuclear Proteins; C007293:DAPI