Article

Pot1 and cell cycle progression cooperate in telomere length regulation

Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, PO Box 0524, Cincinnati, Ohio 45267-0524, USA.
Nature Structural & Molecular Biology (Impact Factor: 11.63). 02/2008; 15(1):79-84. DOI: 10.1038/nsmb1331
Source: PubMed

ABSTRACT Removal of the vertebrate telomere protein Pot1 results in a DNA damage response and cell cycle arrest. Here we show that loss of chicken Pot1 causes Chk1 activation, and inhibition of Chk1 signaling prevents the cell cycle arrest. However, arrest still occurs after disruption of ATM, which encodes another DNA damage response protein. These results indicate that Pot1 is required to prevent a telomere checkpoint mediated by another such protein, ATR, that is most likely triggered by the G-overhang. We also show that removal of Pot1 causes exceptionally rapid telomere growth upon arrest in late S/G2 of the cell cycle. However, release of the arrest slows both telomere growth and G-overhang elongation. Thus, Pot1 seems to regulate telomere length and G-overhang processing both through direct interaction with the telomere and by preventing a late S/G2 delay in the cell cycle. Our results reveal that cell cycle progression is an important component of telomere length regulation.

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