Utilization of ribonucleotides and RNA primers by Tetrahymena telomerase

Collins, K., Greider, C. W. (November 1995) Utilization of ribonucleotides and RNA primers by Tetrahymena telomerase. Embo J, 14 (21). pp. 5422-32. ISSN 0261-4189 (Print)

URL: http://www.ncbi.nlm.nih.gov/pubmed/7489731

Abstract

Telomerase is a ribonucleoprotein (RNP) DNA polymerase involved in telomere synthesis. A short sequence within the telomerase RNA component provides a template for de novo addition of the G-rich strand of a telomeric simple sequence repeat onto chromosome termini. In vitro, telomerase can elongate single-stranded DNA primers processively: one primer can be extended by multiple rounds of template copying before product dissociation. Telomerase will incorporate dNTPs or ddNTPs and will elongate any G-rich, single-stranded primer DNA. In this report, we show that Tetrahymena telomerase was able to incorporate a ribonucleotide, rGTP, into product polynucleotide. Synthesis of the product [d(TT)r(GGGG)]n was processive, suggesting that the chimeric product remained associated with the enzyme both at the active site and at a second, previously characterized, template-independent product binding site. As predicted by this finding, RNA-containing oligonucleotides served as primers for elongation. More than 3 nt of RNA at a primer 3' end decreased the quantity of product synthesis but increased the affinity of the primer for telomerase. Thus, RNA-containing primers were effective as competitive inhibitors of DNA primer elongation by telomerase. These results support the possible evolutionary origin of telomerase as an RNA-dependent RNA polymerase.

Item Type: Paper
Uncontrolled Keywords: Animals Binding, Competitive DNA Primers/genetics/metabolism RNA/genetics/metabolism Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. Ribonucleotides/genetics/metabolism Telomerase/ metabolism Tetrahymena/ enzymology
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification
organism description > animal
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes > telomerase
CSHL Authors:
Communities: CSHL labs
Depositing User: Jessica Koos
Date: 1 November 1995
Date Deposited: 14 Aug 2014 15:57
Last Modified: 14 Aug 2014 15:57
PMCID: PMC394651
URI: http://repository.cshl.edu/id/eprint/30580

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