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A translocation-defective telomerase with low levels of activity and processivity stabilizes short telomeres and confers immortalization

Short, repetitive, G-rich telomeric sequences are synthesized by telomerase, a ribonucleoprotein consisting of telomerase reverse transcriptase (TERT) and an integrally associated RNA. Human TERT (hTERT) can repetitively reverse transcribe its RNA template, acting processively to add multiple telome...

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Autores principales: D'Souza, Yasmin, Chu, Tsz Wai, Autexier, Chantal
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3639057/
https://www.ncbi.nlm.nih.gov/pubmed/23447707
http://dx.doi.org/10.1091/mbc.E12-12-0889
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author D'Souza, Yasmin
Chu, Tsz Wai
Autexier, Chantal
author_facet D'Souza, Yasmin
Chu, Tsz Wai
Autexier, Chantal
author_sort D'Souza, Yasmin
collection PubMed
description Short, repetitive, G-rich telomeric sequences are synthesized by telomerase, a ribonucleoprotein consisting of telomerase reverse transcriptase (TERT) and an integrally associated RNA. Human TERT (hTERT) can repetitively reverse transcribe its RNA template, acting processively to add multiple telomeric repeats onto the same substrate. We investigated whether certain threshold levels of telomerase activity and processivity are required to maintain telomere function and immortalize human cells with limited lifespan. We assessed hTERT variants with mutations in motifs implicated in processivity and interaction with DNA, namely the insertion in fingers domain (V791Y), and the E primer grip motif (W930F). hTERT-W930F and hTERT-V791Y reconstitute reduced levels of DNA synthesis and processivity compared with wild-type telomerase. Of interest, hTERT-W930F is more defective in translocation than hTERT-V791Y. Nonetheless, hTERT-W930F, but not hTERT-V791Y, immortalizes limited-lifespan human cells. Both hTERT-W930F– and hTERT-V791Y–expressing cells harbor short telomeres, measured as signal free ends (SFEs), yet SFEs persist only in hTERT-V791Y cells, which undergo apoptosis, likely as a consequence of a defect in recruitment of hTERT-V791Y to telomeres. Our study is the first to demonstrate that low levels of DNA synthesis—on the order of 20% of wild-type telomerase levels—and extension of as few as three telomeric repeats are sufficient to maintain functional telomeres and immortalize limited-lifespan human cells.
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spelling pubmed-36390572013-07-16 A translocation-defective telomerase with low levels of activity and processivity stabilizes short telomeres and confers immortalization D'Souza, Yasmin Chu, Tsz Wai Autexier, Chantal Mol Biol Cell Articles Short, repetitive, G-rich telomeric sequences are synthesized by telomerase, a ribonucleoprotein consisting of telomerase reverse transcriptase (TERT) and an integrally associated RNA. Human TERT (hTERT) can repetitively reverse transcribe its RNA template, acting processively to add multiple telomeric repeats onto the same substrate. We investigated whether certain threshold levels of telomerase activity and processivity are required to maintain telomere function and immortalize human cells with limited lifespan. We assessed hTERT variants with mutations in motifs implicated in processivity and interaction with DNA, namely the insertion in fingers domain (V791Y), and the E primer grip motif (W930F). hTERT-W930F and hTERT-V791Y reconstitute reduced levels of DNA synthesis and processivity compared with wild-type telomerase. Of interest, hTERT-W930F is more defective in translocation than hTERT-V791Y. Nonetheless, hTERT-W930F, but not hTERT-V791Y, immortalizes limited-lifespan human cells. Both hTERT-W930F– and hTERT-V791Y–expressing cells harbor short telomeres, measured as signal free ends (SFEs), yet SFEs persist only in hTERT-V791Y cells, which undergo apoptosis, likely as a consequence of a defect in recruitment of hTERT-V791Y to telomeres. Our study is the first to demonstrate that low levels of DNA synthesis—on the order of 20% of wild-type telomerase levels—and extension of as few as three telomeric repeats are sufficient to maintain functional telomeres and immortalize limited-lifespan human cells. The American Society for Cell Biology 2013-05-01 /pmc/articles/PMC3639057/ /pubmed/23447707 http://dx.doi.org/10.1091/mbc.E12-12-0889 Text en © 2013 D'Souza et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0). “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society of Cell BD; are registered trademarks of The American Society of Cell Biology.
spellingShingle Articles
D'Souza, Yasmin
Chu, Tsz Wai
Autexier, Chantal
A translocation-defective telomerase with low levels of activity and processivity stabilizes short telomeres and confers immortalization
title A translocation-defective telomerase with low levels of activity and processivity stabilizes short telomeres and confers immortalization
title_full A translocation-defective telomerase with low levels of activity and processivity stabilizes short telomeres and confers immortalization
title_fullStr A translocation-defective telomerase with low levels of activity and processivity stabilizes short telomeres and confers immortalization
title_full_unstemmed A translocation-defective telomerase with low levels of activity and processivity stabilizes short telomeres and confers immortalization
title_short A translocation-defective telomerase with low levels of activity and processivity stabilizes short telomeres and confers immortalization
title_sort translocation-defective telomerase with low levels of activity and processivity stabilizes short telomeres and confers immortalization
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3639057/
https://www.ncbi.nlm.nih.gov/pubmed/23447707
http://dx.doi.org/10.1091/mbc.E12-12-0889
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