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Science 6 June 2008:
Vol. 320. no. 5881, pp. 1341 - 1344
DOI: 10.1126/science.1154819
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Reports

Fission Yeast Pot1-Tpp1 Protects Telomeres and Regulates Telomere Length

Tomoichiro Miyoshi, Junko Kanoh, Motoki Saito, Fuyuki Ishikawa*

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.

* To whom correspondence should be addressed. E-mail: fishikaw{at}lif.kyoto-u.ac.jp

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
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