Est1p as a cell cycle-regulated activator of telomere-bound telomerase.
In Saccharomyces cerevisiae, the telomerase components Est2p, TLC1 RNA, Est1p, and Est3p are thought to form a complex that acts late during chromosome replication (S phase) upon recruitment by Cdc13p, a telomeric DNA binding protein. Consistent with this model, we show that Est1p, Est2p, and Cdc13p are telomere-associated at this time. However, Est2p, but not Est1p, also binds telomeres before late S phase. The cdc13-2 allele has been proposed to be defective in recruitment, yet Est1p and Est2p telomere association persists in cdc13-2 cells. These findings suggest a model in which Est1p binds telomeres late in S phase and interacts with Cdc13p to convert inactive, telomere-bound Est2p to an active form.
Taggart
Andrew K P
AK
Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
Teng
Shu-Chun
SC
Zakian
Virginia A
VA
D000483:Alleles; D002453:Cell Cycle; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D016193:G1 Phase; D005800:Genes, Fungal; D008954:Models, Biological; D016133:Polymerase Chain Reaction; D011233:Precipitin Tests; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D016615:Telomere / Q000378:metabolism*; D034501:Telomere-Binding Proteins
C452219:Cdc13 protein, S cerevisiae; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D034501:Telomere-Binding Proteins; C099024:EST1 protein, S cerevisiae; D019098:Telomerase