Fission yeast Pot1-Tpp1 protects telomeres and regulates telomere length.
Telomeres are specialized chromatin structures that protect chromosomal ends. Protection of telomeres 1 (Pot1) binds to the telomeric G-rich overhang, thereby protecting telomeres and regulating telomerase. Mammalian POT1 and TPP1 interact and constitute part of the six-protein shelterin complex. Here we report that Tpz1, the TPP1 homolog in fission yeast, forms a complex with Pot1. Tpz1 binds to Ccq1 and the previously undiscovered protein Poz1 (Pot1-associated in Schizosaccharomyces pombe), which protect telomeres redundantly and regulate telomerase in positive and negative manners, respectively. Thus, the Pot1-Tpz1 complex accomplishes its functions by recruiting effector molecules Ccq1 and Poz1. Moreover, Poz1 bridges Pot1-Tpz1 and Taz1-Rap1, thereby connecting the single-stranded and double-stranded telomeric DNA regions. Such molecular architectures are similar to those of mammalian shelterin, indicating that the overall DNA-protein architecture is conserved across evolution.
Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
Tomoichiro
T
Miyoshi
Junko
J
Kanoh
Motoki
M
Saito
Fuyuki
F
Ishikawa
D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D004271:DNA, Fungal / Q000378:metabolism; D004268:DNA-Binding Proteins; D047468:Immunoprecipitation; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000089804:Shelterin Complex; D019098:Telomerase / Q000378:metabolism; D016615:Telomere / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D034501:Telomere-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D002352:Carrier Proteins; C529647:Ccq1 protein, S pombe; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; C529645:Poz1 protein, S pombe; C509571:Rap1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D000089804:Shelterin Complex; D034501:Telomere-Binding Proteins; C529646:Tpz1 protein, S pombe; C499082:pot1 protein, S pombe; D019098:Telomerase