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Mrc1 protects uncapped budding yeast telomeres from exonuclease EXO1

Lookup NU author(s): Professor David Lydall



Mrc1 (Mediator of Replication Checkpoint 1) is a component of the DNA replication fork machinery and is necessary for checkpoint activation after replication stress. In this study, we addressed the role of Mrc1 at uncapped telomeres. Our experiments show that Mrc1 contributes to the vitality of both cdc13-1 and yku70Δ telomere capping mutants. Cells with telomere capping defects containing MRC1 or mrc1AQ, a checkpoint defective allele, exhibit similar growth, suggesting growth defects of cdc13-1 mrc1Δ are not due to checkpoint defects. This is in accordance with Mrc1-independent Rad53 activation after telomere uncapping. Poor growth of cdc13-1 mutants in the absence of Mrc1 is a result of enhanced single stranded DNA accumulation at uncapped telomeres. Consistent with this, deletion of EXO1, encoding a nuclease that contributes to single stranded DNA accumulation after telomere uncapping, improves growth of cdc13-1 mrc1Δ strains and decreases ssDNA production. Our observations show that Mrc1, a core component of the replication fork, plays an important role in telomere capping, protecting from nucleases and checkpoint pathways. © 2007 Elsevier B.V. All rights reserved.

Publication metadata

Author(s): Tsolou A, Lydall D

Publication type: Article

Publication status: Published

Journal: DNA Repair

Year: 2007

Volume: 6

Issue: 11

Pages: 1607-1617

Print publication date: 01/11/2007

ISSN (print): 1568-7864

ISSN (electronic): 1568-7856

Publisher: Elsevier BV


DOI: 10.1016/j.dnarep.2007.05.010

PubMed id: 17618841


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Funder referenceFunder name
054371Wellcome Trust
075294Wellcome Trust