title: Cell cycle-dependent regulation of yeast telomerase by Ku.
abstract: The heterodimeric Ku complex affects telomere structure in diverse organisms. We report here that in the absence of Ku, the catalytic subunit of telomerase, Est2p, was not telomere-associated in G1 phase, and its association in late S phase was decreased. The telomere association of Est1p, a telomerase component that binds telomeres only in late S phase, was also reduced in the absence of Ku. The effects of Ku on telomerase binding require a 48-nucleotide (nt) stem-loop region of TLC1 telomerase RNA. Ku interacts with TLC1 RNA via this 48-nt region throughout the cell cycle, but this interaction was reduced after telomere replication. These data support a model in which Ku recruits telomerase to telomeres in G1 phase when telomerase is inactive and promotes telomerase-mediated telomere lengthening in late S phase.
authors.affiliation: Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Fisher
authors.forename: Andrew K P
authors.initials: AK
authors.lastname: Taggart
authors.forename: Virginia A
authors.initials: VA
authors.lastname: Zakian
mesh_terms: D034961:Antigens, Nuclear / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D000072200:Ku Autoantigen; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D012313:RNA / Q000737:chemistry / Q000378:metabolism; D012331:RNA, Fungal / Q000737:chemistry / Q000378:metabolism; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D019098:Telomerase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016615:Telomere / Q000378:metabolism; D034501:Telomere-Binding Proteins / Q000378:metabolism
chemical_list: D034961:Antigens, Nuclear; C452219:Cdc13 protein, S cerevisiae; D004268:DNA-Binding Proteins; D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D034501:Telomere-Binding Proteins; C422952:telomerase RNA; D012313:RNA; D019098:Telomerase; D000072200:Ku Autoantigen