HOS1-mediated activation of FLC via chromatin remodeling under cold stress

Plant Signal Behav. 2013;8(12):e27342. doi: 10.4161/psb.27342. Epub 2013 Dec 31.


The Arabidopsis E3 ubiquitin ligase HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE 1 (HOS1) has been shown to act as a negative regulator of cold responses by degrading the INDUCER OF CBF EXPRESSION 1 (ICE1) transcription factor through the ubiquitin/proteasome pathway. Notably, loss-of-function hos1 mutants exhibit early flowering, and the transcript level of the floral repressor FLOWERING LOCUS C (FLC) is downregulated in the mutants. However, it is largely unknown how HOS1 regulates FLC transcription. We found that HOS1 activates FLC transcription by inhibiting the activity of histone deacetylase 6 (HDA6) under cold stress. Cold temperatures induce the binding of HOS1 to FLC chromatin in an FVE-dependent manner. Cold-activated HOS1 promotes the dissociation of HDA6 from FLC chromatin, and the cold effects disappear in both hos1 and fve mutants. It is therefore clear that HOS1 regulates FLC transcription via chromatin remodeling, providing new insights into the signaling crosstalks between cold response and flowering time control.

Keywords: Arabidopsis; FLC; FVE; HDA6; HOS1; chromatin remodeling; cold stress; flowering time.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism*
  • Chromatin Assembly and Disassembly*
  • Cold Temperature*
  • Flowers / physiology
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • MADS Domain Proteins / metabolism*
  • Models, Biological
  • Nuclear Proteins / metabolism*
  • Stress, Physiological*
  • Time Factors


  • Arabidopsis Proteins
  • FLF protein, Arabidopsis
  • HOS1 protein, Arabidopsis
  • Intracellular Signaling Peptides and Proteins
  • MADS Domain Proteins
  • Nuclear Proteins