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Telomere Homeostasis in Budding Yeast is Regulated by a Single Mechanism Involving Replication Fork Collapse
Author(s) -
Lundblad Vicki,
Paschini Margherita
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.933.5
Subject(s) - replisome , telomere , telomerase , telomere binding protein , dna replication , biology , pre replication complex , replication protein a , replication factor c , minichromosome maintenance , control of chromosome duplication , microbiology and biotechnology , origin recognition complex , eukaryotic dna replication , dna , genetics , dna binding protein , gene , transcription factor
In budding yeast, telomere homeostasis relies on a telomere‐dedicated RPA‐like (t‐RPA) complex composed of the single‐strand DNA binding protein Cdc13 in association with Stn1 and Ten1. While bound to telomeres, the t‐RPA complex recruits telomerase to its site of action, and it performs an essential function which is widely assumed to be protection from unregulated resection. A current model assumes that these two events occur following completion of replication. We present here a substantially different model. Specifically, we propose that the t‐RPA complex is a replication factor which associates with telomeres as the replisome proceeds into the G‐rich telomeric duplex tract. Once associated with the replisome, the t‐RPA complex facilitates replication of duplex telomeric DNA by (i) preventing replication fork collapse, which we propose is the essential role of the t‐RPA complex and (ii) resolving collapsed forks by recruiting telomerase to the site of fork collapse. This model is supported by analysis of the sequence of duplex telomeric DNA in mutant strains, which reveals a role for both t‐RPA and other telomere proteins in progression of the replisome through duplex telomeric DNA.