Telomere shortening in human diseases

Authors

  • Chiou Mee Kong,

    1. Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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  • Xiao Wen Lee,

    1. Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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  • Xueying Wang

    Corresponding author
    1. Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
    • Correspondence

      X. Wang, Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Centre for Translational Medicine, 14 Medical Drive, #10-01, Singapore 117599, Singapore

      Fax: +65 6779 1453

      Tel.: +65 6601 2360

      E-mail: bchwxy@nus.edu.sg

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  • Chiou Mee Kong and Xiao Wen Lee contributed equally to this work

Abstract

The discovery of telomeres dates back to the early 20th century. In humans, telomeres are heterochromatic structures with tandem DNA repeats of 5′-TTAGGG-3′ at the chromosomal ends. Telomere length varies greatly among species and ranges from 10 to 15 kb in humans. With each cell division, telomeres shorten progressively because of the ‘end-replication problem’. Short or dysfunctional telomeres are often recognized as DNA DSBs, triggering cell-cycle arrest and result in cellular senescence or apoptotic cell death. Therefore, telomere shortening serves as an important tumor-suppressive mechanism by limiting cellular proliferative capacity by regulating senescence checkpoint activation. Although telomeres serve as a mitotic clock to cells, they also confer capping on chromosomes, with help from telomere-associated proteins. Over the past decades, many studies of telomere biology have demonstrated that telomeres and telomere-associated proteins are implicated in human genetic diseases. In addition, it has become more apparent that accelerated telomere erosion is associated with a myriad of metabolic and inflammatory diseases. Moreover, critically short or unprotected telomeres are likely to form telomeric fusions, leading to genomic instability, the cornerstone for carcinogenesis. In light of these, this minireview summarizes studies on telomeres and telomere-associated proteins in human diseases. Elucidating the roles of telomeres involved in the mechanisms underlying pathogenesis of these diseases may open up new possibilities for novel molecular targets as well as provide important diagnostic and therapeutic implications.

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