A Single Templating RNA in Yeast Telomerase

Bajon, Emmanuel; Laterreur, Nancy; Wellinger, Raymund J.

doi:10.1016/j.celrep.2015.06.045

Cited by 26 publications

(29 citation statements)

References 33 publications

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“…Native protein extracts for Mass Spectrometry were prepared as described in (Bajon et al, 2015). Detailed procedures can be found in the Supplemental Experimental procedures.…”

Section: Methodsmentioning

confidence: 99%

Active Yeast Telomerase Shares Subunits with Ribonucleoproteins RNase P and RNase MRP

Lemieux

Laterreur

Perederina

et al. 2016

Cell

Self Cite

114

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Summary Telomerase is the ribonucleoprotein enzyme that replenishes telomeric DNA and maintains genome integrity. Minimally, telomerase activity requires a templating RNA and a catalytic protein. Additional proteins are required for activity on telomeres in vivo. Here we report that the Pop1, Pop6, and Pop7 proteins, known components of RNase P and RNase MRP, bind to yeast telomerase RNA and are essential constituents of the telomerase holoenzyme. Pop1/Pop6/Pop7 binding is specific and involves an RNA domain that is highly similar to a protein-binding domain in the RNAs of RNase P/MRP. The results also show that Pop1/Pop6/Pop7 function to maintain the essential components Est1 and Est2 on the RNA in vivo. Consistently, addition of Pop1 allows for telomerase activity reconstitution with wild type telomerase RNA in vitro. Thus, the same chaperoning module has allowed the evolution of functionally and, remarkably, structurally distinct RNPs, telomerase and RNases P/MRP, from unrelated progenitor RNAs.

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“…Native protein extracts for Mass Spectrometry were prepared as described in (Bajon et al, 2015). Detailed procedures can be found in the Supplemental Experimental procedures.…”

Section: Methodsmentioning

confidence: 99%

Active Yeast Telomerase Shares Subunits with Ribonucleoproteins RNase P and RNase MRP

Lemieux

Laterreur

Perederina

et al. 2016

Cell

Self Cite

114

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“…Whole cell protein extracts were prepared as previously described [73]. Samples were analyzed on 8% SDS-PAGE followed by electroblotting onto HybondECL membrane (GE-Healthcare).…”

Section: Methodsmentioning

confidence: 99%

Ku Binding on Telomeres Occurs at Sites Distal from the Physical Chromosome Ends

et al. 2016

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The Ku complex binds non-specifically to DNA breaks and ensures repair via NHEJ. However, Ku is also known to bind directly to telomeric DNA ends and its presence there is associated with telomere capping, but avoiding NHEJ. How the complex discriminates between a DNA break and a telomeric extremity remains unknown. Our results using a tagged Ku complex, or a chromosome end capturing method, in budding yeast show that yKu association with telomeres can occur at sites distant from the physical end, on sub-telomeric elements, as well as on interstitial telomeric repeats. Consistent with previous studies, our results also show that yKu associates with telomeres in two distinct and independent ways: either via protein-protein interactions between Yku80 and Sir4 or via direct DNA binding. Importantly, yKu associates with the new sites reported here via both modes. Therefore, in sir4Δ cells, telomere bound yKu molecules must have loaded from a DNA-end near the transition of non-telomeric to telomeric repeat sequences. Such ends may have been one sided DNA breaks that occur as a consequence of stalled replication forks on or near telomeric repeat DNA. Altogether, the results predict a new model for yKu function at telomeres that involves yKu binding at one-sided DNA breaks caused by replication stalling. On telomere proximal chromatin, this binding is not followed by initiation of non-homologous end-joining, but rather by break-induced replication or repeat elongation by telomerase. After repair, the yKu-distal portion of telomeres is bound by Rap1, which in turn reduces the potential for yKu to mediate NHEJ. These results thus propose a solution to a long-standing conundrum, namely how to accommodate the apparently conflicting functions of Ku on telomeres.

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“…Once in the nucleoplasm, telomerase can be recruited to telomeres (105, 108). Quantitative imaging of TLC1 in cells suggests that each TLC1–monomer RNP diffuses independently through the nucleoplasm until encountering a replicated telomere (109, 110). S. cerevisiae telomerase complexes appear to cluster at telomeres (109), but how this finding relates to requirements for telomere elongation is not known.…”

Section: Cellular Ribonucleoprotein Assembly and Action At Telomeresmentioning

confidence: 99%

Telomerase Mechanism of Telomere Synthesis

Upton

Vogan

et al. 2017

Annu. Rev. Biochem.

192

186

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Telomerase is the essential reverse transcriptase required for linear chromosome maintenance in most eukaryotes. Telomerase supplements the tandem array of simple-sequence repeats at chromosome ends to compensate for the DNA erosion inherent in genome replication. The template for telomerase reverse transcriptase is within the RNA subunit of the ribonucleoprotein complex, which in cells contains additional telomerase holoenzyme proteins that assemble the active ribonucleoprotein and promote its function at telomeres. Telomerase is distinct among polymerases in its reiterative reuse of an internal template. The template is precisely defined, processively copied, and regenerated by release of single-stranded product DNA. New specificities of nucleic acid handling that underlie the catalytic cycle of repeat synthesis derive from both active site specialization and new motif elaborations in protein and RNA subunits. Studies of telomerase provide unique insights into cellular requirements for genome stability, tissue renewal, and tumorigenesis as well as new perspectives on dynamic ribonucleoprotein machines.

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A Single Templating RNA in Yeast Telomerase

Cited by 26 publications

References 33 publications

Active Yeast Telomerase Shares Subunits with Ribonucleoproteins RNase P and RNase MRP

Active Yeast Telomerase Shares Subunits with Ribonucleoproteins RNase P and RNase MRP

Ku Binding on Telomeres Occurs at Sites Distal from the Physical Chromosome Ends

Telomerase Mechanism of Telomere Synthesis

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