title: Conservation and diversification of polycomb repressive complex 2 (PRC2) proteins in the green lineage.
abstract: The polycomb group (PcG) proteins are key epigenetic regulators of gene expression in animals and plants. They act in multiprotein complexes, of which the best characterized is the polycomb repressive complex 2 (PRC2), which catalyses the trimethylation of histone H3 at lysine 27 (H3K27me3) at chromatin targets. In Arabidopsis thaliana, PRC2 proteins are involved in the regulation of diverse developmental processes, including cell fate determination, vegetative growth and development, flowering time control and embryogenesis. Here, we systematically analysed the evolutionary conservation and diversification of PRC2 components in lower and higher plants. We searched for and identified PRC2 homologues from the sequenced genomes of several green lineage species, from the unicellular green alga Ostreococcus lucimarinus to more complicated angiosperms. We found that some PRC2 core components, e.g. E(z), ESC/FIE and MSI/p55, are ancient and have multiplied coincidently with multicellular evolution. For one component, some members are newly formed, especially in the Cruciferae. During evolution, higher plants underwent copy number multiplication of various PRC2 components, which occurred independently for each component, without any obvious co-amplification of PRC2 members. Among the amplified members, usually one was well-conserved and the others were more diversified. Gene amplification occurred at different times for different PcG members during green lineage evolution. Certain PRC2 core components or members of them were highly conserved. Our study provides an insight into the evolutionary conservation and diversification of PcG proteins and may guide future functional characterization of these important epigenetic regulators in plants other than Arabidopsis.
authors.affiliation: College of Bioscience and Biotechnology, International Associated Laboratory of CNRS-FU-HAU On Plant Epigenome Research, Hunan Agricultural University, Changsha, China.|Key Laboratory of Education, Department of Hunan Province On Plant Genetics and Molecular Biology, Hunan Agricultural University, Changsha, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.affiliation: College of Bioscience and Biotechnology, International Associated Laboratory of CNRS-FU-HAU On Plant Epigenome Research, Hunan Agricultural University, Changsha, China.|Key Laboratory of Education, Department of Hunan Province On Plant Genetics and Molecular Biology, Hunan Agricultural University, Changsha, China.
authors.forename: Dong-Hong
authors.initials: DH
authors.lastname: Chen
authors.affiliation: Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, China.
authors.forename: Bo-Yu
authors.initials: BY
authors.lastname: Liu
authors.affiliation: College of Bioscience and Biotechnology, International Associated Laboratory of CNRS-FU-HAU On Plant Epigenome Research, Hunan Agricultural University, Changsha, China.|Institut de Biologie Moléculaire Des Plantes Du CNRS, Université de Strasbourg, 12 Rue Du Général Zimmer, Strasbourg Cedex, France.
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Shen
authors.affiliation: College of Bioscience and Biotechnology, International Associated Laboratory of CNRS-FU-HAU On Plant Epigenome Research, Hunan Agricultural University, Changsha, China.|Key Laboratory of Education, Department of Hunan Province On Plant Genetics and Molecular Biology, Hunan Agricultural University, Changsha, China.|Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Ruan
mesh_terms: D018506:Gene Expression Regulation, Plant; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D010944:Plants / Q000145:classification* / Q000378:metabolism*; D063151:Polycomb Repressive Complex 2 / Q000235:genetics / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs
chemical_list: D010940:Plant Proteins; D063151:Polycomb Repressive Complex 2
keywords: PRC2; domain organization; evolution; phylogenetic analysis; polycomb