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The telomerase essential N-terminal domain promotes DNA synthesis by stabilizing short RNA-DNA hybrids.

Authors
  • Akiyama, Benjamin M1
  • Parks, Joseph W2
  • Stone, Michael D3
  • 1 Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA Center for Molecular Biology of RNA, University of California, Santa Cruz, CA 95064, USA.
  • 2 Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA Center for Molecular Biology of RNA, University of California, Santa Cruz, CA 95064, USA.
  • 3 Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA Center for Molecular Biology of RNA, University of California, Santa Cruz, CA 95064, USA [email protected]
Type
Published Article
Journal
Nucleic Acids Research
Publisher
Oxford University Press
Publication Date
Jun 23, 2015
Volume
43
Issue
11
Pages
5537–5549
Identifiers
DOI: 10.1093/nar/gkv406
PMID: 25940626
Source
Medline
Language
English
License
Unknown

Abstract

Telomerase is an enzyme that adds repetitive DNA sequences to the ends of chromosomes and consists of two main subunits: the telomerase reverse transcriptase (TERT) protein and an associated telomerase RNA (TER). The telomerase essential N-terminal (TEN) domain is a conserved region of TERT proposed to mediate DNA substrate interactions. Here, we have employed single molecule telomerase binding assays to investigate the function of the TEN domain. Our results reveal telomeric DNA substrates bound to telomerase exhibit a dynamic equilibrium between two states: a docked conformation and an alternative conformation. The relative stabilities of the docked and alternative states correlate with the number of basepairs that can be formed between the DNA substrate and the RNA template, with more basepairing favoring the docked state. The docked state is further buttressed by the TEN domain and mutations within the TEN domain substantially alter the DNA substrate structural equilibrium. We propose a model in which the TEN domain stabilizes short RNA-DNA duplexes in the active site of the enzyme, promoting the docked state to augment telomerase processivity. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

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