Identification and characterization of the Schizosaccharomyces pombe TER1 telomerase RNA

Webb, Christopher J.; Zakian, Virginia A.

doi:10.1038/nsmb1354

Cited by 102 publications

(136 citation statements)

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“…Sm proteins associate with S. cerevisiae telomerase RNA, contributing to telomerase maturation and stability (Seto et al 1999). S. pombe telomerase RNA (Ter1) also contains an Sm consensus site (Leonardi et al 2008;Webb and Zakian 2008). The canonical Sm ring and the related Lsm2 -8 complex sequentially associate with S. pombe Ter1 (Tang et al 2012).…”

Section: Telomerasementioning

confidence: 99%

Replication of Telomeres and the Regulation of Telomerase

Pfeiffer

Lingner

2013

Cold Spring Harbor Perspectives in Biology

110

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Telomeres are the physical ends of eukaryotic chromosomes. They protect chromosome ends from DNA degradation, recombination, and DNA end fusions, and they are important for nuclear architecture. Telomeres provide a mechanism for their replication by semiconservative DNA replication and length maintenance by telomerase. Through telomerase repression and induced telomere shortening, telomeres provide the means to regulate cellular life span. In this review, we introduce the current knowledge on telomere composition and structure. We then discuss in depth the current understanding of how telomere components mediate their function during semiconservative DNA replication and how telomerase is regulated at the end of the chromosome. We focus our discussion on the telomeres from mammals and the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe.

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Section: Telomerasementioning

confidence: 99%

Replication of Telomeres and the Regulation of Telomerase

Pfeiffer

Lingner

2013

Cold Spring Harbor Perspectives in Biology

110

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“…In vivo analysis of the STE region of TER1. (A) Model for the TER1 secondary structure (6). The TWJ and TER1-1067-1078 regions are enlarged to show detail.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the STE is critical to assemble the normal sequence and chromatin structure of fission yeast telomeres. humans, the predicted secondary structure for the S. pombe TER1 STE contains both a TWJ and P6.1 helix and loop, making S. pombe an excellent model for the human STE (6,15) (Fig. 1 A and B).…”

Section: Significancementioning

confidence: 99%

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Telomerase RNA stem terminus element affects template boundary element function, telomere sequence, and shelterin binding

Webb

Zakian

2015

Proc. Natl. Acad. Sci. U.S.A.

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The stem terminus element (STE), which was discovered 13 y ago in human telomerase RNA, is required for telomerase activity, yet its mode of action is unknown. We report that the Schizosaccharomyces pombe telomerase RNA, TER1 (telomerase RNA 1), also contains a STE, which is essential for telomere maintenance. Cells expressing a partial loss-of-function TER1 STE allele maintained short stable telomeres by a recombination-independent mechanism. Remarkably, the mutant telomere sequence was different from that of wild-type cells. Generation of the altered sequence is explained by reverse transcription into the template boundary element, demonstrating that the STE helps maintain template boundary element function. The altered telomeres bound less Pot1 (protection of telomeres 1) and Taz1 (telomere-associated in Schizosaccharomyces pombe 1) in vivo. Thus, the S. pombe STE, although distant from the template, ensures proper telomere sequence, which in turn promotes proper assembly of the shelterin complex.T he specialized reverse-transcriptase telomerase compensates for the inability of the conventional semiconservative replication machinery to copy the very end of the chromosome. In addition to solving this "end replication problem," telomeres perform other roles, such as protecting chromosomes from degradation and end-to-end fusions, a function that requires both telomeric DNA and telomere-associated proteins. In the fission yeast Schizosaccharomyces pombe, telomeric DNA is bound and protected by a six-protein complex that has many similarities to mammalian shelterin. S. pombe shelterin protects the telomere, inhibits nonhomologous end joining, facilitates telomere replication, and recruits telomerase (1-3).The shelterin complex binds both double-stranded (ds) telomeric DNA and the terminal single-stranded (ss) guanine-rich overhang, known as the G-tail (3). The ds region of S. pombe telomeres is bound by the Myb domain of the S. pombe shelterin component Taz1 (telomere-associated in Schizosaccharomyces pombe 1), whereas the G-tail is bound by the OB domains of Pot1 (protection of telomeres 1). Both the Myb and OB (oligonucleotide/oligosaccharidebinding) domains are present in the mammalian homologs of these proteins, TRF1/TRF2 and POT1, respectively (1-3).Although telomeric DNA almost always consists of short repeats, the fidelity of these repeats is not perfect in most organisms, including humans (4). In S. pombe, repeat heterogeneity is particularly high. Although the core S. pombe telomere repeat 5′-GGTTACA-3′ is incorporated at high levels, heterogeneity is created by the inclusion of 1-6 guanines before the core repeat and more rarely by the addition of a cytosine at the end of the repeat. These additions yield a telomere consensus sequence of 5′-(G) 0-6 GGTTACAC-3′ (rare cytosine is underlined throughout this paper). Almost half (42%) of the telomeric repeats are preceded by a guanine tract of 1-6 Gs, whereas the rare cytosine is present in ∼12% of the repeats (5). The (G) 1-6 tracts result from template stut...

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“…Although TERT has clear sequence conservation among divergent organisms, the RNA subunit shows little primary sequence conservation even between closely related species. More surprisingly, the length of telomerase RNA varies widely among eukaryotes; it ranges from 150-200 nt for ciliates (10,11) and 300-500 nt for vertebrates (12) to more than 1 kb for budding and fission yeasts (13)(14)(15).…”

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confidence: 99%

Engineering cis-telomerase RNAs that add telomeric repeats to themselves

Qiao¹,

Goodrich²,

Cech³

2010

Proc. Natl. Acad. Sci. U.S.A.

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Telomerase is a ribonucleoprotein complex consisting of a protein reverse transcriptase (TERT) and an RNA subunit (TR). Telomerase normally adds telomeric DNA repeats to chromosome ends. Here, we engineer human and Tetrahymena cis-telomerase RNAs, each having a DNA primer covalently linked to its 3′ end. We find that cis-telomerase synthesizes DNA with increased repeat addition processivity (RAP) but does not completely rescue the RAP defect of the L14A mutant of Tetrahymena TERT. This supports the conclusion that L14 has a function beyond binding the DNA primer and preventing dissociation during multiple rounds of repeat addition. By comparing cis-telomerases with various linker lengths, we find that a 5 nt linker gives near-optimal activity, indicating that the distance between the 3′ end of the telomerase RNA pseudoknot region and the 5′ end of the DNA primer is ∼33 Å. Even a 2 nt linker (∼14 Å) gives some activity, indicating a high degree of conformational flexibility in this ribonucleoprotein complex. More generally, the cis system will allow structure-function relationships of each RNA molecule to be read directly through the reaction that it performs on itself.ribonucleoprotein complex | processivity | reverse transcriptase | telomerase N atural RNAs involved in biocatalysis act either "in cis" (intramolecular reactions) or "in trans" (intermolecular reactions). Cis-acting RNAs are exemplified by the self-splicing group I and group II introns and the self-cleaving hammerhead and hairpin ribozymes (1, 2). Trans-acting RNAs include: the ribosomal RNAs that use aminoacylated tRNAs as substrates (3), the spliceosomal small nuclear RNAs that use pre-mRNAs as substrates (4), and the RNase P ribozyme that uses tRNA precursors containing 5′-leader sequences as substrates (5). In a number of cases, cis-acting ribozymes have been converted into trans-acting RNA enzymes that splice or cleave exogenous RNA substrates. The incentive for engineering these trans-acting ribozymes was initially to demonstrate that they were true catalysts, capable of multiple-turnover reactions. A subsequent rationale was to create RNA-cleaving agents for biotechnology. Transformation in the other direction, from trans-acting to cis-acting RNAs, has been accomplished for RNase P. By engineering a chimeric RNA that joins the RNase P RNA to its pre-tRNA substrate, pre-tRNA-RNase P RNA conjugates were designed to undergo accurate and efficient self-cleavage (6, 7). In the present work, we describe the conversion of the telomerase RNA-TERT complex, which normally acts in trans to extend telomeric DNA primers, into a cis-acting system that extends its own 3′ end. Thus, a trans-acting RNA can be converted into a cis-acting RNA even in the context of a complex ribonucleoprotein (RNP).The telomerase RNP uses its reverse transcriptase subunit (TERT) to copy a template sequence within its intrinsic RNA subunit (TR), thereby adding telomeric DNA repeats to the ends of chromosomes (8, 9). Although TERT has clear sequence conservation among divergent...

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Identification and characterization of the Schizosaccharomyces pombe TER1 telomerase RNA

Cited by 102 publications

References 59 publications

Replication of Telomeres and the Regulation of Telomerase

Replication of Telomeres and the Regulation of Telomerase

Telomerase RNA stem terminus element affects template boundary element function, telomere sequence, and shelterin binding

Engineering cis-telomerase RNAs that add telomeric repeats to themselves

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