HMG domain containing SSRP1 is required for DNA demethylation and genomic imprinting in Arabidopsis

Dev Cell. 2011 Sep 13;21(3):589-96. doi: 10.1016/j.devcel.2011.08.013.


In Arabidopsis, DEMETER (DME) DNA demethylase contributes to reprogramming of the epigenetic state of the genome in the central cell. However, other aspects of the active DNA demethylation processes remain elusive. Here we show that Arabidopsis SSRP1, known as an HMG domain-containing component of FACT histone chaperone, is required for DNA demethylation and for activation and repression of many parentally imprinted genes in the central cell. Although loss of DNA methylation releases silencing of the imprinted FWA-GFP, double ssrp1-3;met1-3 mutants surprisingly showed limited activation of maternal FWA-GFP in the central cell, and only became fully active after several nuclear divisions in the endosperm. This behavior was in contrast to the dme-1;met1 double mutant in which hypomethylation of FWA-GFP by met1 suppressed the DNA demethylation defect of dme-1. We propose that active DNA demethylation by DME requires SSRP1 function through a distinctly different process from direct DNA methylation control.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomal Proteins, Non-Histone / metabolism*
  • DNA (Cytosine-5-)-Methyltransferases / genetics
  • DNA (Cytosine-5-)-Methyltransferases / metabolism
  • DNA Methylation*
  • Gene Expression Regulation, Plant
  • Gene Silencing
  • Genomic Imprinting*
  • HMG-Box Domains*
  • Histone Chaperones / metabolism*
  • N-Glycosyl Hydrolases / genetics
  • N-Glycosyl Hydrolases / metabolism*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*


  • Arabidopsis Proteins
  • Chromosomal Proteins, Non-Histone
  • Histone Chaperones
  • Trans-Activators
  • MET1 protein, Arabidopsis
  • DNA (Cytosine-5-)-Methyltransferases
  • DEMETER protein, Arabidopsis
  • N-Glycosyl Hydrolases