Tetrahymena telomerase catalyzes nucleolytic cleavage and nonprocessive elongation

Collins, K., Greider, C. W. (July 1993) Tetrahymena telomerase catalyzes nucleolytic cleavage and nonprocessive elongation. Genes Dev, 7 (7B). pp. 1364-76. ISSN 0890-9369 (Print)

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URL: http://www.ncbi.nlm.nih.gov/pubmed/8330740
DOI: 10.1101/gad.7.7b.1364


Telomerase is a ribonucleoprotein enzyme that adds telomeric repeats to chromosomes, maintaining telomere length and stabilizing chromosome ends. In vitro, telomerase from the ciliate Tetrahymena elongates single-stranded, guanosine-rich DNA primers by adding repeats of the Tetrahymena telomeric sequence, dT2G4. We have identified two activities of Tetrahymena telomerase in addition to the previously described processive elongation reaction: a 3'-5' nucleolytic cleavage of primer or product DNA and a nonprocessive mode of elongation. The nucleolytic cleavage activity removed residues not conforming to the telomeric repeat sequence from a primer 3' end, eliminating mismatch between DNA primer and RNA template sequences. Template-matched residues were also cleaved from primer or product DNA. Specific primer lengths, sequences, and concentrations stimulated cleavage and processive or nonprocessive elongation differentially. These newly identified activities suggest that telomerase may catalyze a range of telomere synthesis and repair functions and suggest mechanistic similarities between telomerase and RNA polymerase enzymes. On the basis of our results, we propose a model for telomerase primer binding, cleavage, and elongation.

Item Type: Paper
Uncontrolled Keywords: Animals Base Sequence Catalysis Cell Nucleolus/metabolism DNA Nucleotidylexotransferase/ metabolism DNA, Protozoan/ metabolism DNA, Single-Stranded/metabolism Deoxyguanine Nucleotides/metabolism Hydrolysis Molecular Sequence Data Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. Templates, Genetic Tetrahymena/ enzymology
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification
organs, tissues, organelles, cell types and functions > organelles, types and functions > nucleus
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes > telomerase
CSHL Authors:
Communities: CSHL labs > Greider lab
Depositing User: Matt Covey
Date: July 1993
Date Deposited: 19 Apr 2016 14:40
Last Modified: 03 Nov 2017 20:40
Related URLs:
URI: https://repository.cshl.edu/id/eprint/32513

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