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Mechanistic Analysis of HP1 heterochromatin assembly
Author(s) -
Narlikar Geeta,
Canzio Daniele,
Liao Maofu,
Naber Nariman,
Pate Ed,
Larson Adam,
Wu Shenping,
Cooke Roger,
Schuck Peter,
Cheng Yifan
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.456.3
Subject(s) - heterochromatin protein 1 , chromodomain , heterochromatin , nucleosome , chromatin , histone , ezh2 , microbiology and biotechnology , biology , genetics , chemistry , dna , helicase , rna , gene
The most conserved form of heterochromatin is characterized by methylation of lysine 9 on histone H3 (H3K9me3). Key to both the assembly and the spreading process is the heterochromatin protein 1 (HP1), which binds the H3K9me3 mark via its chromodomain (CD). This interaction forms a versatile platform for recruitment of different types of chromatin modifying proteins. However, the molecular basis of how the HP1‐H3K9me3 chromatin complex achieves these diverse interactions is yet to be understood. Our previous work on the S. pombe HP1 protein, Swi6, suggested that four molecules of Swi6 bind one nucleosome generating two vacant CDs, that can bridge adjacent nucleosomes. Our new data suggests that Swi6 switches between an auto‐inhibited state and bridging competent state upon binding methylated chromatin. We will present the biochemical data that lead to this model and an initial EM structure of Swi6 bound to nucleosomes that is consistent with this model. Our data also suggest testable hypothesis for how specific post‐translation modification on Swi6 can regulate its association with methylated chromatin and its interaction with the different heterochromatin proteins.