title: Mutations in Ran system affected telomere silencing in Saccharomyces cerevisiae.
abstract: The Ran GTPase system regulates the direction and timing of several cellular events, such as nuclear-cytosolic transport, centrosome formation, and nuclear envelope assembly in telophase. To gain insight into the Ran system's involvement in chromatin formation, we investigated gene silencing at the telomere in several mutants of the budding yeast Saccharomyces cerevisiae, which had defects in genes involved in the Ran system. A mutation of the RanGAP gene, rna1-1, caused reduced silencing at the telomere, and partial disruption of the nuclear Ran binding factor, yrb2-delta2, increased this silencing. The reduced telomere silencing in rna1-1 cells was suppressed by a high dosage of the SIR3 gene or the SIT4 gene. Furthermore, hyperphosphorylated Sir3 protein accumulated in the rna1-1 mutant. These results suggest that RanGAP is required for the heterochromatin structure at the telomere in budding yeast.
authors: Department of Molecular Pathology, Cancer Research Institute, Kanazawa University, Kanazawa, Ishikawa 920-0934, Japan. naoyuki@kenroku.kanazawa-u.ac.jp
authors: Naoyuki
authors: N
authors: Hayashi
authors: Masahiko
authors: M
authors: Kobayashi
authors: Hiroko
authors: H
authors: Shimizu
authors: Ken-ichi
authors: K
authors: Yamamoto
authors: Seishi
authors: S
authors: Murakami
authors: Takeharu
authors: T
authors: Nishimoto
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D020690:GTPase-Activating Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D016615:Telomere / Q000235:genetics*
chemical_list: D018797:Cell Cycle Proteins; D020690:GTPase-Activating Proteins; D009687:Nuclear Proteins; C060997:RNA1 protein, S cerevisiae; C084122:SIR3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; C113422:YRB2 protein, S cerevisiae