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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2005-9-30
pubmed:abstractText
In eukaryotes, heterochromatin mediates diverse processes including gene silencing and regulation of long-range chromatin interactions. The formation of heterochromatin involves a conserved array of histone modifications; in particular, methylation of histone H3 at Lys 9 (H3K9me) is essential for recruiting HP1/Swi6 proteins. In fission yeast, the Clr4 methyltransferase is responsible for H3K9me across all heterochromatic domains. However, the mechanism of Clr4 recruitment to these loci is poorly understood. We show that Clr4 associates with Cul4, a cullin family protein that serves as a scaffold for assembling ubiquitin ligases. Mutations in Cul4 result in defective localization of Clr4 and loss of silencing at heterochromatic loci. This is accompanied by a severe reduction in H3K9me and Swi6 levels, and accumulation of transcripts corresponding to naturally silenced repeat elements within heterochromatic domains. Moreover, heterochromatin defects in Cul4 mutants could not be rescued by expression of Cul4 protein lacking Nedd8 modification, which is essential for its ubiquitin ligase activity. Rik1, a protein related to DNA damage binding protein DDB1 and required for H3K9me, also interacts with Cul4, the association of which might serve to target Clr4 to heterochromatic loci. These analyses uncover a role for Cul4-based protein ubiquitination in regulating H3K9me and heterochromatin formation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Cell Cycle Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Cullin Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Heterochromatin, http://linkedlifedata.com/resource/pubmed/chemical/Histone-Lysine N-Methyltransferase, http://linkedlifedata.com/resource/pubmed/chemical/Histones, http://linkedlifedata.com/resource/pubmed/chemical/Methyltransferases, http://linkedlifedata.com/resource/pubmed/chemical/Protein Methyltransferases, http://linkedlifedata.com/resource/pubmed/chemical/Schizosaccharomyces pombe Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Ubiquitin-Protein Ligases, http://linkedlifedata.com/resource/pubmed/chemical/clr4 protein, S pombe, http://linkedlifedata.com/resource/pubmed/chemical/histone methyltransferase
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1465-7392
pubmed:author
pubmed:issnType
Print
pubmed:volume
7
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1007-13
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Ubiquitin ligase component Cul4 associates with Clr4 histone methyltransferase to assemble heterochromatin.
pubmed:affiliation
Laboratory of Molecular Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
pubmed:publicationType
Letter, Research Support, N.I.H., Intramural