title: Modulations of SIR-nucleosome interactions of reconstructed yeast silent pre-heterochromatin by O-acetyl-ADP-ribose and magnesium.
abstract: Yeast silent heterochromatin provides an excellent model with which to study epigenetic inheritance. Previously we developed an in vitro assembly system to demonstrate the formation of filament structures with requirements that mirror yeast epigenetic gene silencing in vivo. However, the properties of these filaments were not investigated in detail. Here we show that the assembly system requires Sir2, Sir3, Sir4, nucleosomes, and O-acetyl-ADP-ribose. We also demonstrate that all Sir proteins and nucleosomes are components of these filaments to prove that they are SIR-nucleosome filaments. Furthermore, we show that the individual localization patterns of Sir proteins on the SIR-nucleosome filament reflect those patterns on telomeres in vivo. In addition, we reveal that magnesium exists in the SIR-nucleosome filament, with a role similar to that for chromatin condensation. These results suggest that a small number of proteins and molecules are sufficient to mediate the formation of a minimal yeast silent pre-heterochromatin in vitro.
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan.
authors.forename: Shu-Yun
authors.initials: SY
authors.lastname: Tung
authors.affiliation: Department of Biomedical Sciences, Chung Shan Medical University, Taichung 402, Taiwan.
authors.forename: Sue-Hong
authors.initials: SH
authors.lastname: Wang
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan.
authors.forename: Sue-Ping
authors.initials: SP
authors.lastname: Lee
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan.
authors.forename: Shu-Ping
authors.initials: SP
authors.lastname: Tsai
authors.affiliation: Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 350, Taiwan.
authors.forename: Hsiao-Hsuian
authors.initials: HH
authors.lastname: Shen
authors.affiliation: Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 350, Taiwan.
authors.forename: Feng-Jung
authors.initials: FJ
authors.lastname: Chen
authors.affiliation: Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 350, Taiwan.
authors.forename: Yu-Yi
authors.initials: YY
authors.lastname: Wu
authors.affiliation: Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 350, Taiwan.
authors.forename: Sheng-Pin
authors.initials: SP
authors.lastname: Hsiao
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan bogun@gate.sinica.edu.tw emguang@yahoo.com.tw.|Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 350, Taiwan.|Guang EM Laboratory, New Taipei 242, Taiwan.
authors.forename: Gunn-Guang
authors.initials: GG
authors.lastname: Liou
mesh_terms: D001665:Binding Sites; D002843:Chromatin / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly; D057890:Epigenomics / Q000379:methods; D020868:Gene Silencing / Q000502:physiology*; D006570:Heterochromatin / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D008274:Magnesium; D009707:Nucleosomes / Q000378:metabolism*; D038961:O-Acetyl-ADP-Ribose / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D037761:Sirtuins / Q000378:metabolism; D016615:Telomere / Q000378:metabolism
chemical_list: D002843:Chromatin; D006570:Heterochromatin; D006657:Histones; D009707:Nucleosomes; D038961:O-Acetyl-ADP-Ribose; C084122:SIR3 protein, S cerevisiae; C061573:SIR4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D037761:Sirtuins; D008274:Magnesium