title: H2A monoubiquitination in Arabidopsis thaliana is generally independent of LHP1 and PRC2 activity.
abstract: Polycomb group complexes PRC1 and PRC2 repress gene expression at the chromatin level in eukaryotes. The classic recruitment model of Polycomb group complexes in which PRC2-mediated H3K27 trimethylation recruits PRC1 for H2A monoubiquitination was recently challenged by data showing that PRC1 activity can also recruit PRC2. However, the prevalence of these two mechanisms is unknown, especially in plants as H2AK121ub marks were examined at only a handful of Polycomb group targets.
  
  
  
  By using genome-wide analyses, we show that H2AK121ub marks are surprisingly widespread in Arabidopsis thaliana, often co-localizing with H3K27me3 but also occupying a set of transcriptionally active genes devoid of H3K27me3. Furthermore, by profiling H2AK121ub and H3K27me3 marks in atbmi1a/b/c, clf/swn, and lhp1 mutants we found that PRC2 activity is not required for H2AK121ub marking at most genes. In contrast, loss of AtBMI1 function impacts the incorporation of H3K27me3 marks at most Polycomb group targets.
  
  
  
  Our findings show the relationship between H2AK121ub and H3K27me3 marks across the A. thaliana genome and unveil that ubiquitination by PRC1 is largely independent of PRC2 activity in plants, while the inverse is true for H3K27 trimethylation.
authors.affiliation: Max Planck Institute for Plant Breeding Research, Department of Plant Developmental Biology, Cologne, Germany.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Computer Science and Artificial Intelligence, University of Sevilla, Seville, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Romero-Campero
authors.affiliation: Institute of Plant Biochemistry and Photosynthesis (IBVF-CSIC-University of Sevilla), Seville, Spain.
authors.forename: Ángeles
authors.initials: Á
authors.lastname: Gómez-Zambrano
authors.affiliation: Max Planck Institute for Plant Breeding Research, Department of Plant Developmental Biology, Cologne, Germany. turck@mpipz.mpg.de.
authors.forename: Franziska
authors.identifier: 0000-0002-4982-5949
authors.initials: F
authors.lastname: Turck
authors.affiliation: Institute of Plant Biochemistry and Photosynthesis (IBVF-CSIC-University of Sevilla), Seville, Spain. myriam.calonje@ibvf.csic.es.
authors.forename: Myriam
authors.initials: M
authors.lastname: Calonje
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D063150:Polycomb Repressive Complex 1 / Q000235:genetics; D063151:Polycomb Repressive Complex 2; D063146:Polycomb-Group Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination; D002868:Chromosomal Proteins, Non-Histone
chemical_list: D029681:Arabidopsis Proteins; D002843:Chromatin; D005964:Glucosyltransferases; D006657:Histones; D063150:Polycomb Repressive Complex 1; D063151:Polycomb Repressive Complex 2; D063146:Polycomb-Group Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C548103:AT1G52740 protein, Arabidopsis; C574170:PRC2 protein, Arabidopsis; C457769:PRC1 protein, Arabidopsis; C477788:At5g17690 protein, Arabidopsis; D002868:Chromosomal Proteins, Non-Histone
keywords: Arabidopsis thaliana; H2AK121ub; H3K27me3; PRC1; PRC2; Polycomb group repression mechanism