This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Cunningham, D. D. Articles by Collins, K. Search for Related Content PubMed PubMed Citation Articles by Cunningham, D. D. Articles by Collins, K.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, June 2005, p. 4442-4454, Vol. 25, No. 11
0270-7306/05/$08.00+0     doi:10.1128/MCB.25.11.4442-4454.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Biological and Biochemical Functions of RNA in the Tetrahymena Telomerase Holoenzyme

Doreen D. Cunningham and Kathleen Collins^*

Department of Molecular and Cell Biology, University of California, Berkeley, California

Received 2 February 2005/ Returned for modification 23 February 2005/ Accepted 8 March 2005

Telomerase extends chromosome ends by the synthesis of tandem simple-sequence repeats. Studies of minimal recombinant telomerase ribonucleoprotein (RNP) reconstituted in vitro have revealed sequences within the telomerase RNA subunit (TER) that are required to establish its internal template and other unique features of enzyme activity. Here we test the significance of these motifs following TER assembly into telomerase holoenzyme in vivo. We established a method for stable expression of epitope-tagged TER and TER variants in place of wild-type Tetrahymena TER. We found that sequence substitutions in nontemplate regions of TER altered telomere length maintenance in vivo, with an increase or decrease in the set point for telomere length homeostasis. We also characterized the in vitro activity of the telomerase holoenzymes reconstituted with TER variants, following RNA-based RNP affinity purification from cell extracts. We found that nontemplate sequence substitutions imposed specific defects in the fidelity and processivity of template use. These findings demonstrate nontemplate functions of TER that are critical for the telomerase holoenzyme catalytic cycle and for proper telomere length maintenance in vivo.

---

* Corresponding author. Mailing address: Department of Molecular and Cell Biology, 16 Barker Hall, University of California, Berkeley, CA 94720-3204. Phone: (510) 643-1598. Fax: (510) 643-6334. E-mail: kcollins{at}berkeley.edu.

---

Molecular and Cellular Biology, June 2005, p. 4442-4454, Vol. 25, No. 11
0022-538X/05/$08.00+0     doi:10.1128/MCB.25.11.4442-4454.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Errington, T. M., Fu, D., Wong, J. M. Y., Collins, K. (2008). Disease-Associated Human Telomerase RNA Variants Show Loss of Function for Telomere Synthesis without Dominant-Negative Interference. Mol. Cell. Biol. 28: 6510-6520 [Abstract] [Full Text]  
• Ulyanov, N. B., Shefer, K., James, T. L., Tzfati, Y. (2007). Pseudoknot structures with conserved base triples in telomerase RNAs of ciliates. Nucleic Acids Res 35: 6150-6160 [Abstract] [Full Text]  
• Lue, N. F., Li, Z. (2007). Modeling and structure function analysis of the putative anchor site of yeast telomerase. Nucleic Acids Res 0: gkm531v1-10 [Abstract] [Full Text]  
• Romi, E., Baran, N., Gantman, M., Shmoish, M., Min, B., Collins, K., Manor, H. (2007). High-resolution physical and functional mapping of the template adjacent DNA binding site in catalytically active telomerase. Proc. Natl. Acad. Sci. USA 104: 8791-8796 [Abstract] [Full Text]  
• Witkin, K. L., Prathapam, R., Collins, K. (2007). Positive and Negative Regulation of Tetrahymena Telomerase Holoenzyme. Mol. Cell. Biol. 27: 2074-2083 [Abstract] [Full Text]