'Poisoning' yeast telomeres distinguishes between redundant telomere capping pathways
| Autor: | Noa Lamm, Shhadeh Bsoul, Majdi M. Kabaha, Yehuda Tzfati |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Telomerase
DNA End-Joining Repair Telomere Capping Recombinant Fusion Proteins RAD52 Telomere-Binding Proteins Biology Fungal Proteins chemistry.chemical_compound Kluyveromyces Genetics Cloning Molecular Genetics (clinical) Repetitive Sequences Nucleic Acid Telomere-binding protein Recombination Genetic Tetrahymena Cell Cycle Checkpoints Telomere biology.organism_classification Molecular biology chemistry Homologous recombination DNA |
| Zdroj: | Chromosoma. 121(6) |
| ISSN: | 1432-0886 |
| Popis: | In most eukaryotes, telomeres are composed of tandem arrays of species-specific DNA repeats ending with a G-rich 3' overhang. In budding yeast, Cdc13 binds this overhang and recruits Ten1-Stn1 and the telomerase protein Est1 to protect (cap) and elongate the telomeres, respectively. To dissect and study the various pathways employed to cap and maintain the telomere end, we engineered telomerase to incorporate Tetrahymena telomeric repeats (G₄T₂) onto the telomeres of the budding yeast Kluyveromyces lactis. These heterologous repeats caused telomere-telomere fusions, cell cycle arrest at G2/M, and severely reduced viability--the hallmarks of telomere uncapping. Fusing Cdc13 or Est1 to universal minicircle sequence binding protein (UMSBP), a small protein that binds the single-stranded G₄T₂ repeats, rescued the cell viability and restored telomere capping, but not telomerase-mediated telomere maintenance. Surprisingly, Cdc13-UMSBP-mediated telomere capping was dependent on the homologous recombination factor Rad52, while Est1-UMSBP was not. Thus, our results distinguish between two, redundant, telomere capping pathways. |
| Databáze: | OpenAIRE |
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