Telomere and telomerase in stem cells

Hiyama Eiso

Hiyama Keiko

British Journal of Cancer

Telomeres, guanine-rich tandem DNA repeats of the chromosomal end, provide chromosomal stability, and cellular replication causes their loss. In somatic cells, the activity of telomerase, a reverse transcriptase that can elongate telomeric repeats, is usually diminished after birth so that the telomere length is gradually shortened with cell divisions, and triggers cellular senescence. In embryonic stem cells, telomerase is activated and maintains telomere length and cellular immortality; however, the level of telomerase activity is low or absent in the majority of stem cells regardless of their proliferative capacity. Thus, even in stem cells, except for embryonal stem cells and cancer stem cells, telomere shortening occurs during replicative aging, possibly at a slower rate than that in normal somatic cells. Recently, the importance of telomere maintenance in human stem cells has been highlighted by studies on dyskeratosis congenital, which is a genetic disorder in the human telomerase component. The regulation of telomere length and telomerase activity is a complex and dynamic process that is tightly linked to cell cycle regulation in human stem cells. Here we review the role of telomeres and telomerase in the function and capacity of the human stem cells.

telomere

telomerase

stem cell

cancer stem cell

dyskeratosis congenita

Botany [ 470 ]

eng

Nature Publishing Group

Copyright (c) 2007 Cancer Research UK

[ISSN] 0007-0920

[DOI] 10.1038/sj.bjc.6603671

[PMID] 17353922

[NCID] AA00574355

[DOI] http://dx.doi.org/10.1038/sj.bjc.6603671