title: Sde2: a novel nuclear protein essential for telomeric silencing and genomic stability in Schizosaccharomyces pombe.
abstract: Telomeres, specialized domains assembled at the ends of linear chromosomes, are essential for genomic stability in eukaryotes. The formation and maintenance of telomeres are governed by numerous factors such as telomeric repeats, telomere-binding proteins, heterochromatin proteins, and telomerase. Here, we report Sde2, a novel nuclear protein essential for telomeric silencing and genomic stability in the fission yeast Schizosaccharomyces pombe. A deficiency in sde2 results in the derepression of the ura4(+) gene inserted near telomeric repeats, and the noncoding transcripts from telomeric regions accumulate in sde2Δ cells. The loss of Sde2 function compromises transcriptional silencing at telomeres, and this silencing defect is accompanied by increased levels of acetylated histone H3K14 and RNA polymerase II occupancy at telomeres as well as reduced recruitment of the SNF2 ATPase/histone deacetylase-containing complex SHREC to telomeres. Deletion of sde2 also leads to a higher frequency of mitotic minichromosome loss, and sde2Δ cells often form asci that contain spores in abnormal numbers, shapes, or both. In addition, sde2Δ cells are highly sensitive to several stresses, including high/low temperatures, bleomycin, which induces DNA damage, and thiabendazole, a microtubule-destabilizing agent. Furthermore, Sde2 genetically interacts with the telomere regulators Taz1, Pof3, and Ccq1. These findings demonstrate that Sde2 cooperates with other telomere regulators to maintain functional telomeres, thereby preventing genomic instability.
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Sugioka-Sugiyama
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Sugiyama
mesh_terms: D000595:Amino Acid Sequence; D001761:Bleomycin / Q000494:pharmacology; D043171:Chromosomal Instability; D044783:F-Box Proteins / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D042822:Genomic Instability; D006655:Histone Deacetylases / Q000378:metabolism; D008540:Meiosis / Q000235:genetics; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D012568:Schizosaccharomyces / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism; D016615:Telomere / Q000235:genetics* / Q000378:metabolism; D034501:Telomere-Binding Proteins / Q000378:metabolism; D013696:Temperature
chemical_list: C529647:Ccq1 protein, S pombe; D044783:F-Box Proteins; D009687:Nuclear Proteins; C514993:Pof3 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D034501:Telomere-Binding Proteins; C104344:taz1 protein, S pombe; C400810:ura4 protein, S pombe; D001761:Bleomycin; D006655:Histone Deacetylases