Telomerase RNA Template Mutations Reveal Sequence-Specific Requirements for the Activation and Repression of Telomerase Action at Telomeres

Telomeric DNA is maintained within a length range characteristic of an organism or cell type. Significant deviations outside this range are associated with altered telomere function. The yeast telomere-binding protein Rap1p negatively regulates telomere length. Telomere elongation is responsive to b...

Description complète

Enregistré dans:
Détails bibliographiques
Auteurs principaux: Prescott, John C., Blackburn, Elizabeth H.
Format: Article
Langue:en
Publié: American Society for Microbiology 2000
Sujets:
DNA Dynamics and Chromosome Structure
Accès en ligne:https://ncbi.nlm.nih.gov/pmc/articles/PMC85540/
https://ncbi.nlm.nih.gov/pubmed/10733598
Tags: Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
id pubmed-85540
record_format dspace
spelling pubmed-855402002-09-13 Telomerase RNA Template Mutations Reveal Sequence-Specific Requirements for the Activation and Repression of Telomerase Action at Telomeres Prescott, John C. Blackburn, Elizabeth H. Mol Cell Biol DNA Dynamics and Chromosome Structure Telomeric DNA is maintained within a length range characteristic of an organism or cell type. Significant deviations outside this range are associated with altered telomere function. The yeast telomere-binding protein Rap1p negatively regulates telomere length. Telomere elongation is responsive to both the number of Rap1p molecules bound to a telomere and the Rap1p-centered DNA-protein complex at the extreme telomeric end. Previously, we showed that a specific trinucleotide substitution in the Saccharomyces cerevisiae telomerase gene (TLC1) RNA template abolished the enzymatic activity of telomerase, causing the same cell senescence and telomere shortening phenotypes as a complete tlc1 deletion. Here we analyze effects of six single- and double-base changes within these same three positions. All six mutant telomerases had in vitro enzymatic activity levels similar to the wild-type levels. The base changes predicted from the mutations all disrupted Rap1p binding in vitro to the corresponding duplex DNAs. However, they caused two classes of effects on telomere homeostasis: (i) rapid, RAD52-independent telomere lengthening and poor length regulation, whose severity correlated with the decrease in in vitro Rap1p binding affinity (this is consistent with loss of negative regulation of telomerase action at these telomeres; and (ii) telomere shortening that, depending on the template mutation, either established a new short telomere set length with normal cell growth or was progressive and led to cellular senescence. Hence, disrupting Rap1p binding at the telomeric terminus is not sufficient to deregulate telomere elongation. This provides further evidence that both positive and negative cis-acting regulators of telomerase act at telomeres. American Society for Microbiology 2000-04 /pmc/articles/PMC85540/ /pubmed/10733598 Text en Copyright © 2000, American Society for Microbiology
institution US National Library of Medicine
collection PubMed Central
language en
format Article
topic DNA Dynamics and Chromosome Structure
spellingShingle DNA Dynamics and Chromosome Structure
Prescott, John C.
Blackburn, Elizabeth H.
Telomerase RNA Template Mutations Reveal Sequence-Specific Requirements for the Activation and Repression of Telomerase Action at Telomeres
description Telomeric DNA is maintained within a length range characteristic of an organism or cell type. Significant deviations outside this range are associated with altered telomere function. The yeast telomere-binding protein Rap1p negatively regulates telomere length. Telomere elongation is responsive to both the number of Rap1p molecules bound to a telomere and the Rap1p-centered DNA-protein complex at the extreme telomeric end. Previously, we showed that a specific trinucleotide substitution in the Saccharomyces cerevisiae telomerase gene (TLC1) RNA template abolished the enzymatic activity of telomerase, causing the same cell senescence and telomere shortening phenotypes as a complete tlc1 deletion. Here we analyze effects of six single- and double-base changes within these same three positions. All six mutant telomerases had in vitro enzymatic activity levels similar to the wild-type levels. The base changes predicted from the mutations all disrupted Rap1p binding in vitro to the corresponding duplex DNAs. However, they caused two classes of effects on telomere homeostasis: (i) rapid, RAD52-independent telomere lengthening and poor length regulation, whose severity correlated with the decrease in in vitro Rap1p binding affinity (this is consistent with loss of negative regulation of telomerase action at these telomeres; and (ii) telomere shortening that, depending on the template mutation, either established a new short telomere set length with normal cell growth or was progressive and led to cellular senescence. Hence, disrupting Rap1p binding at the telomeric terminus is not sufficient to deregulate telomere elongation. This provides further evidence that both positive and negative cis-acting regulators of telomerase act at telomeres.
author Prescott, John C.
Blackburn, Elizabeth H.
author_facet Prescott, John C.
Blackburn, Elizabeth H.
author_sort Prescott, John C.
title Telomerase RNA Template Mutations Reveal Sequence-Specific Requirements for the Activation and Repression of Telomerase Action at Telomeres
title_short Telomerase RNA Template Mutations Reveal Sequence-Specific Requirements for the Activation and Repression of Telomerase Action at Telomeres
title_full Telomerase RNA Template Mutations Reveal Sequence-Specific Requirements for the Activation and Repression of Telomerase Action at Telomeres
title_fullStr Telomerase RNA Template Mutations Reveal Sequence-Specific Requirements for the Activation and Repression of Telomerase Action at Telomeres
title_full_unstemmed Telomerase RNA Template Mutations Reveal Sequence-Specific Requirements for the Activation and Repression of Telomerase Action at Telomeres
title_sort telomerase rna template mutations reveal sequence-specific requirements for the activation and repression of telomerase action at telomeres
publisher American Society for Microbiology
publisher_facet American Society for Microbiology
publishDate 2000
url https://ncbi.nlm.nih.gov/pmc/articles/PMC85540/
https://ncbi.nlm.nih.gov/pubmed/10733598
_version_ 1759028708438441984

Documents similaires