Silent information regulator protein complexes in Saccharomyces cerevisiae: A SIR2/SIR4 complex and evidence for a regulatory domain in SIR4 that inhibits its interaction with SIR3
AUTOR(ES)
Moazed, Danesh
FONTE
The National Academy of Sciences of the USA
RESUMO
The SIR2, SIR3, and SIR4 silent information regulator proteins are involved in the assembly of silent chromatin domains in the budding yeast Saccharomyces cerevisiae. Using a series of biochemical experiments, we have studied protein–protein interactions involving these proteins. We found that yeast extracts contained a SIR2/SIR4 complex that was associated with little or no SIR3. However, truncations of the N-terminal two-thirds of the SIR4 protein allowed it to efficiently associate with SIR3, suggesting that the N-terminal domain of SIR4 inhibited its interaction with SIR3. We propose that the SIR3 and SIR4 proteins interact only during the assembly of the SIR protein complex at the silencer and that an early step in assembly unmasks the SIR4 protein to allow its association with SIR3. To test whether the interactions observed in yeast extracts were direct, we tested these SIR-SIR interactions using bacterially expressed SIR proteins. We observed direct interactions between SIR4 and SIR2, SIR4 and SIR3, SIR2 and SIR3, SIR2 and SIR2, and SIR4 and SIR4, indicating that the associations observed in yeast extracts were direct.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=20062Documentos Relacionados
- Genetic evidence for an interaction between SIR3 and histone H4 in the repression of the silent mating loci in Saccharomyces cerevisiae.
- Map Positions of Yeast Genes SIR1, SIR3 and SIR4
- Steps in Assembly of Silent Chromatin in Yeast: Sir3-Independent Binding of a Sir2/Sir4 Complex to Silencers and Role for Sir2-Dependent Deacetylation
- The Origin Recognition Complex and Sir4 Protein Recruit Sir1p to Yeast Silent Chromatin through Independent Interactions Requiring a Common Sir1p Domain
- Enhancement of Telomere-Plasmid Segregation by the X-Telomere Associated Sequence in Saccharomyces Cerevisiae Involves Sir2, Sir3, Sir4 and Abf1