Gene Silencing

TFIID Polycomb Repressive Complex 2 (PRC2) is essential for gene silencing, establishing transcriptional repression of specific genes by tri-methylating Lysine 27 of histone H3. In spite of its biological importance, little was known about PRC2 architecture and subunit organization. We have reconstituted a tetrameric human PRC2 complex (Ezh2/EED/Suz12/RbAp48) with its cofactor AEBP2 and obtained the only available structural description of the complex (20 Å resolution). We used a tagging strategy to position all functional domains within the complex that showed that the Ezh2’s SET domain forms a core with the two activity-controlling elements, the WD40 domain of EED and the VEFS domain of Suz12. How PRC2 interacts with nucleosomes, or its interaction with ncRNAs are among our next goals.

See also:

Claudio Ciferri, Gabriel C. Lander, Alessio Maiolica, Franz Herzog, Ruedi Aebersold and Eva Nogales (2012) Molecular architecture of Polycomb Repressive Complex 2. eLife, 1:e00005 Oct 30 2012 Epub.