The carboxy termini of Sir4 and Rap1 affect Sir3 localization: evidence for a multicomponent complex required for yeast telomeric silencing
| Autor: | Francesca Palladino, Moira M. Cockell, G Kyrion, C Liu, Susan M. Gasser, Arthur J. Lustig, Thierry Laroche |
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| Rok vydání: | 1995 |
| Předmět: |
endocrine system
Macromolecular Substances Saccharomyces cerevisiae Fluorescent Antibody Technique Plasma protein binding Fungal Proteins Structure-Activity Relationship Silent Information Regulator Proteins medicine Nuclear protein Psychological repression Silent Information Regulator Proteins Saccharomyces cerevisiae Cell Nucleus Fungal protein biology Nuclear Proteins SIR proteins Articles Cell Biology Telomere biology.organism_classification Precipitin Tests Molecular biology Peptide Fragments Recombinant Proteins Cell Compartmentation enzymes and coenzymes (carbohydrates) Cell nucleus medicine.anatomical_structure Solubility Trans-Activators Rap1 Protein Binding Transcription Factors |
| Zdroj: | The Journal of Cell Biology |
| ISSN: | 1540-8140 0021-9525 |
| DOI: | 10.1083/jcb.129.4.909 |
| Popis: | The Silent Information Regulatory proteins, Sir3 and Sir4, and the telomeric repeat-binding protein RAP1 are required for the chromatin-mediated gene repression observed at yeast telomeric regions. All three proteins are localized by immunofluorescence staining to foci near the nuclear periphery suggesting a relationship between subnuclear localization and silencing. We present several lines of immunological and biochemical evidence that Sir3, Sir4, and RAP1 interact in intact yeast cells. First, immunolocalization of Sir3 to foci at the yeast nuclear periphery is lost in rap1 mutants carrying deletions for either the terminal 28 or 165 amino acids of RAP1. Second, the perinuclear localization of both Sir3 and RAP1 is disrupted by overproduction of the COOH terminus of Sir4. Third, overproduction of the Sir4 COOH terminus alters the solubility properties of both Sir3 and full-length Sir4. Finally, we demonstrate that RAP1 and Sir4 coprecipitate in immune complexes using either anti-RAP1 or anti-Sir4 antibodies. We propose that the integrity of a tertiary complex between Sir4, Sir3, and RAP1 is involved in both the maintenance of telomeric repression and the clustering of telomeres in foci near the nuclear periphery. |
| Databáze: | OpenAIRE |
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