Parental epigenetic asymmetry of PRC2-mediated histone modifications in the Arabidopsis endosperm

EMBO J. 2016 Jun 15;35(12):1298-311. doi: 10.15252/embj.201593534. Epub 2016 Apr 25.

Abstract

Parental genomes in the endosperm are marked by differential DNA methylation and are therefore epigenetically distinct. This epigenetic asymmetry is established in the gametes and maintained after fertilization by unknown mechanisms. In this manuscript, we have addressed the key question whether parentally inherited differential DNA methylation affects de novo targeting of chromatin modifiers in the early endosperm. Our data reveal that polycomb-mediated H3 lysine 27 trimethylation (H3K27me3) is preferentially localized to regions that are targeted by the DNA glycosylase DEMETER (DME), mechanistically linking DNA hypomethylation to imprinted gene expression. Our data furthermore suggest an absence of de novo DNA methylation in the early endosperm, providing an explanation how DME-mediated hypomethylation of the maternal genome is maintained after fertilization. Lastly, we show that paternal-specific H3K27me3-marked regions are located at pericentromeric regions, suggesting that H3K27me3 and DNA methylation are not necessarily exclusive marks at pericentromeric regions in the endosperm.

Keywords: DEMETER; DNA methylation; Polycomb Repressive Complex 2; endosperm; genomic imprinting.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics*
  • Arabidopsis Proteins / metabolism*
  • DNA Methylation
  • Endosperm / genetics*
  • Epigenesis, Genetic*
  • Gene Expression Regulation, Plant*
  • Histone Code*
  • Histones / metabolism*
  • Repressor Proteins / metabolism*

Substances

  • Arabidopsis Proteins
  • Histones
  • PRC2 protein, Arabidopsis
  • Repressor Proteins