title: Nap1 regulates proper CENP-B binding to nucleosomes.
abstract: CENP-B is a widely conserved centromeric satellite DNA-binding protein, which specifically binds to a 17-bp DNA sequence known as the CENP-B box. CENP-B functions positively in the de novo assembly of centromeric nucleosomes, containing the centromere-specific histone H3 variant, CENP-A. At the same time, CENP-B also prevents undesired assembly of the CENP-A nucleosome through heterochromatin formation on satellite DNA integrated into ectopic sites. Therefore, improper CENP-B binding to chromosomes could be harmful. However, no CENP-B eviction mechanism has yet been reported. In the present study, we found that human Nap1, an acidic histone chaperone, inhibited the non-specific binding of CENP-B to nucleosomes and apparently stimulated CENP-B binding to its cognate CENP-B box DNA in nucleosomes. In human cells, the CENP-B eviction activity of Nap1 was confirmed in model experiments, in which the CENP-B binding to a human artificial chromosome or an ectopic chromosome locus bearing CENP-B boxes was significantly decreased when Nap1 was tethered near the CENP-B box sequence. In contrast, another acidic histone chaperone, sNASP, did not promote CENP-B eviction in vitro and in vivo and did not stimulate specific CENP-B binding to CENP-A nucleosomes in vitro. We therefore propose a novel mechanism of CENP-B regulation by Nap1.
authors: Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors: Hiroaki
authors: H
authors: Tachiwana
authors: Yuta
authors: Y
authors: Miya
authors: Nobuaki
authors: N
authors: Shono
authors: Jun-ichirou
authors: J
authors: Ohzeki
authors: Akihisa
authors: A
authors: Osakabe
authors: Koichiro
authors: K
authors: Otake
authors: Vladimir
authors: V
authors: Larionov
authors: William C
authors: WC
authors: Earnshaw
authors: Hiroshi
authors: H
authors: Kimura
authors: Hiroshi
authors: H
authors: Masumoto
authors: Hitoshi
authors: H
authors: Kurumizaka
mesh_terms: D001324:Autoantigens / Q000737:chemistry / Q000378:metabolism; D002503:Centromere / Q000378:metabolism; D000076247:Centromere Protein A; D051936:Centromere Protein B / Q000737:chemistry / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000378:metabolism; D002877:Chromosomes, Human / Q000378:metabolism; D004276:DNA, Satellite / Q000737:chemistry; D024202:Electrophoretic Mobility Shift Assay; D006657:Histones / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins / Q000378:metabolism; D009707:Nucleosomes / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D012359:tRNA Methyltransferases
chemical_list: D001324:Autoantigens; C000619700:CENPA protein, human; D000076247:Centromere Protein A; D051936:Centromere Protein B; D002868:Chromosomal Proteins, Non-Histone; D004276:DNA, Satellite; D006657:Histones; D008869:Microtubule-Associated Proteins; C489390:NASP protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D009707:Nucleosomes; D011506:Proteins; C076744:cytoplasmic linker protein 170; C498548:TRMO protein, human; D012359:tRNA Methyltransferases