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Pcl‐PRC2 is needed to generate high levels of H3‐K27 trimethylation at Polycomb target genes
Author(s) -
Nekrasov Maxim,
Klymenko Tetyana,
Fraterman Sven,
Papp Bernadett,
Oktaba Katarzyna,
Köcher Thomas,
Cohen Adrian,
Stunnenberg Hendrik G,
Wilm Matthias,
Müller Jürg
Publication year - 2007
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7601837
Subject(s) - prc2 , histone h3 , polycomb group proteins , biology , chromatin , gene , genetics , microbiology and biotechnology , gene expression , repressor
PRC2 is thought to be the histone methyltransferase (HMTase) responsible for H3‐K27 trimethylation at Polycomb target genes. Here we report the biochemical purification and characterization of a distinct form of Drosophila PRC2 that contains the Polycomb group protein polycomblike (Pcl). Like PRC2, Pcl‐PRC2 is an H3‐K27‐specific HMTase that mono‐, di‐ and trimethylates H3‐K27 in nucleosomes in vitro . Analysis of Drosophila mutants that lack Pcl unexpectedly reveals that Pcl‐PRC2 is required to generate high levels of H3‐K27 trimethylation at Polycomb target genes but is dispensable for the genome‐wide H3‐K27 mono‐ and dimethylation that is generated by PRC2. In Pcl mutants, Polycomb target genes become derepressed even though H3‐K27 trimethylation at these genes is only reduced and not abolished, and even though targeting of the Polycomb protein complexes PhoRC and PRC1 to Polycomb response elements is not affected. Pcl‐PRC2 is thus the HMTase that generates the high levels of H3‐K27 trimethylation in Polycomb target genes that are needed to maintain a Polycomb‐repressed chromatin state.