Histone acetylation recruits the SWR1 complex to regulate active DNA demethylation in Arabidopsis

Proc Natl Acad Sci U S A. 2019 Aug 13;116(33):16641-16650. doi: 10.1073/pnas.1906023116. Epub 2019 Jul 30.

Abstract

Active DNA demethylation is critical for controlling the DNA methylomes in plants and mammals. However, little is known about how DNA demethylases are recruited to target loci, and the involvement of chromatin marks in this process. Here, we identify 2 components of the SWR1 chromatin-remodeling complex, PIE1 and ARP6, as required for ROS1-mediated DNA demethylation, and discover 2 SWR1-associated bromodomain-containing proteins, AtMBD9 and nuclear protein X1 (NPX1). AtMBD9 and NPX1 recognize histone acetylation marks established by increased DNA methylation 1 (IDM1), a known regulator of DNA demethylation, redundantly facilitating H2A.Z deposition at IDM1 target loci. We show that at some genomic regions, H2A.Z and DNA methylation marks coexist, and H2A.Z physically interacts with ROS1 to regulate DNA demethylation and antisilencing. Our results unveil a mechanism through which DNA demethylases can be recruited to specific target loci exhibiting particular histone marks, providing a conceptual framework to understand how chromatin marks regulate DNA demethylation.

Keywords: DNA demethylation pathway; bromodomain; chromatin remodeling; gene silencing; histone variant.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism*
  • Chromatin / metabolism
  • DNA Demethylation*
  • Gene Silencing
  • Histones / metabolism*
  • Models, Biological
  • Multiprotein Complexes / metabolism*
  • Mutation / genetics
  • Protein Binding
  • Protein Subunits / metabolism

Substances

  • Arabidopsis Proteins
  • Chromatin
  • Histones
  • Multiprotein Complexes
  • Protein Subunits