A Rik1-associated, cullin-dependent E3 ubiquitin ligase is essential for heterochromatin formation
| Autor: | Jean-Noel M. Bastie, Craig L. Peterson, Peter J. Horn |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Euchromatin
Chromosomal Proteins Non-Histone Heterochromatin Recombinant Fusion Proteins Ubiquitin-Protein Ligases Genes Fungal Cell Cycle Proteins Biology Schizosaccharomyces Genetics Heterochromatin assembly Cullin Proteins EZH2 Histone-Lysine N-Methyltransferase Methyltransferases Research Papers Ubiquitin ligase Protein Subunits Biochemistry Multiprotein Complexes Mutation biology.protein Heterochromatin protein 1 Schizosaccharomyces pombe Proteins Cullin Developmental Biology |
| Zdroj: | Genes & Development. 19:1705-1714 |
| ISSN: | 1549-5477 0890-9369 |
| DOI: | 10.1101/gad.1328005 |
| Popis: | Heterochromatin is critical for proper centromere and telomere function, and it plays a key role in the transcriptional silencing of specific genomic loci. In fission yeast, the Rik1 protein functions with the Clr4 histone methyltransferase at an early step in heterochromatin formation. Here, we use mass spectrometry and tandem affinity purification of a Rik1-TAP fusion protein to identify Rik1-associated proteins. These studies identify two novel proteins, Raf1 and Raf2, which we find are required for H3-K9 methylation and for transcriptional silencing within centromeric heterochromatin. We also find that subunits of a cullin-dependent E3 ubiquitin ligase are associated with Rik1 and Clr4, and Rik1-TAP preparations exhibit robust E3 ubiquitin ligase activity. Furthermore, expression of a dominant-negative allele of the Pcu4 cullin subunit disrupts regulation of K4 methylation within heterochromatin. These studies provide evidence for a novel Rik1-associated E3 ubiquitin ligase that is required for heterochromatin formation. |
| Databáze: | OpenAIRE |
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