Article | Published:

Yeast telomerase subunit Est1p has guanine quadruplex–promoting activity that is required for telomere elongation

Nature Structural & Molecular Biology volume 17, pages 202209 (2010) | Download Citation

Abstract

Telomeres are eukaryotic protein–DNA complexes found at the ends of linear chromosomes that are essential for maintaining genome integrity and are implicated in cellular aging and cancer. The guanine (G)-rich strand of telomeric DNA, usually elongated by the telomerase reverse transcriptase, can form a higher-order structure known as a G-quadruplex in vitro and in vivo. Several factors that promote or resolve G-quadruplexes have been identified, but the functional importance of these structures for telomere maintenance is not well understood. Here we show that the yeast telomerase subunit Est1p, known to be involved in telomerase recruitment to telomeres, can convert single-stranded telomeric G-rich DNA into a G-quadruplex structure in vitro in a Mg2+-dependent manner. Cells carrying Est1p mutants deficient in G-quadruplex formation in vitro showed gradual telomere shortening and cellular senescence, indicating a positive regulatory role for G-quadruplex in the maintenance of telomere length.

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Acknowledgements

We are grateful to Y. Tsukamoto (Iwate College of Nursing), D. Gottschling (Fred Hutchinson Cancer Research Center), S.-C. Teng (Department of Microbiology, College of Medicine, National Taiwan University), V. Zakian (Department of Molecular Biology, Princeton University) and V. Lundblad (The Salk Institute for Biological Studies) for providing the plasmids and yeast strains. We thank L.-X. Xu for antibody preparations, B.A. Lenzmeier and J. Peng for their critical reading of our manuscript and Y. Hu for creating the image of Figure 7. This work is supported by a Chinese Academy of Sciences–Max Planck Society Professorship and by grants from the Natural Science Foundation of China (NSFC30630018) and the Ministry of Science and Technology (2005CB522402/2007CB914502) to J.-Q.Z.

Author information

Author notes

    • Ming-Liang Zhang
    •  & Xia-Jing Tong

    These authors contributed equally to this work.

Affiliations

  1. The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, The Graduate School of the Chinese Academy of Sciences, Shanghai, China.

    • Ming-Liang Zhang
    • , Xia-Jing Tong
    • , Xiao-Hong Fu
    • , Bo O Zhou
    • , Jianyong Wang
    • , Xin-Hua Liao
    • , Qian-Jin Li
    • , Ning Shen
    • , Jianping Ding
    •  & Jin-Qiu Zhou

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Contributions

M.-L.Z. and X.-J.T. proposed the project, performed most of the experiments, interpreted the data, designed experiments and wrote the manuscript; X.-H.F, B.O.Z., J.W., X.-H.L and Q.-J.L performed some of the experiments; N.S. and J.D. helped with the structure modeling; J.-Q.Z. supervised the project, designed the experiments, interpreted the data and wrote the manuscript.

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The authors declare no competing financial interests.

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Correspondence to Jin-Qiu Zhou.

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https://doi.org/10.1038/nsmb.1760

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