title: Polycomb-like 3 promotes polycomb repressive complex 2 binding to CpG islands and embryonic stem cell self-renewal.
abstract: Polycomb repressive complex 2 (PRC2) trimethylates lysine 27 of histone H3 (H3K27me3) to regulate gene expression during diverse biological transitions in development, embryonic stem cell (ESC) differentiation, and cancer. Here, we show that Polycomb-like 3 (Pcl3) is a component of PRC2 that promotes ESC self-renewal. Using mass spectrometry, we identified Pcl3 as a Suz12 binding partner and confirmed Pcl3 interactions with core PRC2 components by co-immunoprecipitation. Knockdown of Pcl3 in ESCs increases spontaneous differentiation, yet does not affect early differentiation decisions as assessed in teratomas and embryoid bodies, indicating that Pcl3 has a specific role in regulating ESC self-renewal. Consistent with Pcl3 promoting PRC2 function, decreasing Pcl3 levels reduces H3K27me3 levels while overexpressing Pcl3 increases H3K27me3 levels. Furthermore, chromatin immunoprecipitation and sequencing (ChIP-seq) reveal that Pcl3 co-localizes with PRC2 core component, Suz12, and depletion of Pcl3 decreases Suz12 binding at over 60% of PRC2 targets. Mutation of conserved residues within the Pcl3 Tudor domain, a domain implicated in recognizing methylated histones, compromises H3K27me3 formation, suggesting that the Tudor domain of Pcl3 is essential for function. We also show that Pcl3 and its paralog, Pcl2, exist in different PRC2 complexes but bind many of the same PRC2 targets, particularly CpG islands regulated by Pcl3. Thus, Pcl3 is a component of PRC2 critical for ESC self-renewal, histone methylation, and recruitment of PRC2 to a subset of its genomic sites.
authors.affiliation: Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, USA.
authors.forename: Julie
authors.initials: J
authors.lastname: Hunkapiller
authors.forename: Yin
authors.initials: Y
authors.lastname: Shen
authors.forename: Aaron
authors.initials: A
authors.lastname: Diaz
authors.forename: Gerard
authors.initials: G
authors.lastname: Cagney
authors.forename: David
authors.initials: D
authors.lastname: McCleary
authors.forename: Miguel
authors.initials: M
authors.lastname: Ramalho-Santos
authors.forename: Nevan
authors.initials: N
authors.lastname: Krogan
authors.forename: Bing
authors.initials: B
authors.lastname: Ren
authors.forename: Jun S
authors.initials: JS
authors.lastname: Song
authors.forename: Jeremy F
authors.initials: JF
authors.lastname: Reiter
mesh_terms: D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics; D002454:Cell Differentiation; D049109:Cell Proliferation; D018899:CpG Islands / Q000235:genetics; D053595:Embryonic Stem Cells / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D056484:Jumonji Domain-Containing Histone Demethylases / Q000378:metabolism; D008745:Methylation; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics; D063151:Polycomb Repressive Complex 2; D063146:Polycomb-Group Proteins; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; C568886:Mtf2 protein, mouse; D009687:Nuclear Proteins; C574689:Pcl3 protein, mouse; D063146:Polycomb-Group Proteins; D012097:Repressor Proteins; C494163:Suz12 protein, mouse; D056484:Jumonji Domain-Containing Histone Demethylases; C523761:Kdm6b protein, mouse; D063151:Polycomb Repressive Complex 2