Genetic and molecular identification of three human TPP1 functions in telomerase action: recruitment, activation, and homeostasis set point regulation
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Genes Dev.-2014-Sexton-1885-99.pdf
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1.94 MB
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Checksum (MD5)
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Author(s)
Sexton, Alec N.
Regalado, Samuel G.
Cost, Gregory J.
O’Neil, Colleen M.
Urnov, Fyodor D.
Gregory, Philip D.
Collins, Kathleen
Hockemeyer, Dirk
Lai, Christine S.
Jaenisch, Rudolf
Date Issued
August 2014
Journal
Genes & Development
Publisher
Cold Spring Harbor Laboratory Press
Citation
Sexton, Alec N. et al. “Genetic and Molecular Identification of Three Human TPP1 Functions in Telomerase Action: Recruitment, Activation, and Homeostasis Set Point Regulation.” Genes & Development 28, 17 (August 2014): 1885–1899 © 2014 Sexton et al
Version
Final published version
Abstract
Telomere length homeostasis is essential for the long-term survival of stem cells, and its set point determines the proliferative capacity of differentiated cell lineages by restricting the reservoir of telomeric repeats. Knockdown and overexpression studies in human tumor cells showed that the shelterin subunit TPP1 recruits telomerase to telomeres through a region termed the TEL patch. However, these studies do not resolve whether the TPP1 TEL patch is the only mechanism for telomerase recruitment and whether telomerase regulation studied in tumor cells is representative of nontransformed cells such as stem cells. Using genome engineering of human embryonic stem cells, which have physiological telomere length homeostasis, we establish that the TPP1 TEL patch is genetically essential for telomere elongation and thus long-term cell viability. Furthermore, genetic bypass, protein fusion, and intragenic complementation assays define two distinct additional mechanisms of TPP1 involvement in telomerase action at telomeres. We demonstrate that TPP1 provides an essential step of telomerase activation as well as feedback regulation of telomerase by telomere length, which is necessary to determine the appropriate telomere length set point in human embryonic stem cells. These studies reveal and resolve multiple TPP1 roles in telomere elongation and stem cell telomere length homeostasis. Keywords: embryonic stem cells; human genome engineering; shelterin; telomerase telomere maintenance
MIT Department
Massachusetts Institute of Technology. Department of Biology
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Creative Commons Attribution-NonCommercial 4.0 International
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DOI of Published Version
https://doi.org/10.1101/GAD.246819.114
