title: Identification and characterization of nucleoplasmin 3 as a histone-binding protein in embryonic stem cells.
abstract: Embryonic stem (ES) cells are thought to have unique chromatin structures responsible for their capacity for self-renewal and pluripotency. To examine this possibility, we sought nuclear proteins in mouse ES cells that specifically bind to histones using a pull-down assay with synthetic peptides of histone H3 and H4 tail domain as baits. Nuclear proteins preferentially bound to the latter. We identified 45 proteins associated with the histone H4 tail and grouped them into four categories: 10 chromatin remodeling proteins, five histone chaperones, two histone modification-related proteins, and 28 other proteins. mRNA expression levels of 20 proteins selected from these 45 proteins were compared between undifferentiated and retinoic acid (RA)-induced differentiated ES cells. All of the genes were similarly expressed in both states of ES cells, except nucleoplasmin 3 (NPM3) that was expressed at a higher level in the undifferentiated cells. NPM3 proteins were localized in the nucleoli and nuclei of the cells and expression was decreased during RA-induced differentiation. When transfected with NPM3 gene, ES cells significantly increased their proliferation compared with control cells. The present study strongly suggests that NPM3 is a chromatin remodeling protein responsible for the unique chromatin structure and replicative capacity of ES cells.
authors.affiliation: Developmental Biology Laboratory, Department of Biological Science, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan.
authors.forename: Natsuki
authors.initials: N
authors.lastname: Motoi
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Suzuki
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Hirota
authors.forename: Penny
authors.initials: P
authors.lastname: Johnson
authors.forename: Ken
authors.initials: K
authors.lastname: Oofusa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kikuchi
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Yoshizato
mesh_terms: D000818:Animals; D002455:Cell Division / Q000502:physiology; D002460:Cell Line; D049109:Cell Proliferation; D042002:Chromatin Assembly and Disassembly / Q000502:physiology*; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism*; D006657:Histones / Q000378:metabolism*; D051379:Mice; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D056489:Nucleoplasmins; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D014212:Tretinoin / Q000502:physiology
chemical_list: D006657:Histones; C533552:Npm2 protein, mouse; D009687:Nuclear Proteins; D056489:Nucleoplasmins; D010750:Phosphoproteins; D014212:Tretinoin