title: The Ctf18 RFC-like complex positions yeast telomeres but does not specify their replication time.
abstract: Chromosome ends in Saccharomyces cerevisiae are positioned in clusters at the nuclear rim. We report that Ctf18, Ctf8, and Dcc1, the subunits of a Replication Factor C (RFC)-like complex, are essential for the perinuclear positioning of telomeres. In both yeast and mammalian cells, peripheral nuclear positioning of chromatin during G1 phase correlates with late DNA replication. We find that the mislocalized telomeres of ctf18 cells still replicate late, showing that late DNA replication does not require peripheral positioning during G1. The Ku and Sir complexes have been shown to act through separate pathways to position telomeres, but in the absence of Ctf18 neither pathway can act fully to maintain telomere position. Surprisingly CTF18 is not required for Ku or Sir4-mediated peripheral tethering of a nontelomeric chromosome locus. Our results suggest that the Ctf18 RFC-like complex modifies telomeric chromatin to make it competent for normal localization to the nuclear periphery.
authors.affiliation: Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Hiraga
authors.forename: E Douglas
authors.initials: ED
authors.lastname: Robertson
authors.forename: Anne D
authors.initials: AD
authors.lastname: Donaldson
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D016193:G1 Phase; D051818:Replication Protein C / Q000235:genetics / Q000378:metabolism*; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D000089804:Shelterin Complex; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D016615:Telomere / Q000235:genetics / Q000502:physiology*; D034501:Telomere-Binding Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C092693:CTF18 protein, S cerevisiae; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; C429768:Ctf8 protein, S cerevisiae; D004268:DNA-Binding Proteins; C429769:Dcc1 protein, S cerevisiae; C440829:RAP1 protein, S cerevisiae; C061573:SIR4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D000089804:Shelterin Complex; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D034501:Telomere-Binding Proteins; D014157:Transcription Factors; C081647:high affinity DNA-binding factor, S cerevisiae; D051818:Replication Protein C